/

PB98-916203

NTSB/HAR-98/01

NATIONAL

TRANSPORTATION

SAFETY

BOARD

WASHINGTON, D.C. 20594

HIGHWAY ACCIDENT REPORT

MULTIPLE VEHICLE CROSSOVER ACCIDENT

SLINGER, WISCONSIN

FEBRUARY 12, 1997

6832B

U.S. GOVERNMENT PRINTING OFFICE: 1989 0-942-865
Abstract: About 5:52 a.m. on February 12, 1997, a doubles truck that was traveling northbound

on U.S. Route 41 near Slinger, Wisconsin, lost control and crossed over the median into the

southbound lanes. A flatbed truck traveling southbound on U.S. Route 41 collided with the

doubles truck, lost control, and crossed over the median into the northbound lanes. A northbound

passenger van struck and underrode the right front side of the flatbed truck. A refrigerator truck

struck the right rear side of the flatbed truck. Eight persons suffered fatal injuries.

The safety issues discussed in this report are: judgment and experience of the doubles

truckdriver; stability of doubles trucks; effectiveness of snow and ice removal; adequacy of the

American Association of State Highway and Transportation Officials divided freeway median

barrier warrants; adequacy of the States’ accident report forms to capture cross-median accident

data; and availability and use of restraints.

As a result of its investigation, the National Transportation Safety Board issued

recommendations to the Federal Highway Administration, the National Highway Traffic Safety

Administration, the National Association of Governors’ Highway Safety Representatives, the

American Trucking Associations, the Motor Freight Carrier Association, the International

Brotherhood of Teamsters, the American Association of State Highway and Transportation

Officials, the Wisconsin Department of Transportation, the Independent Truckers and Drivers

Association, the National Private Truck Council, and the Owner-Operators Independent Drivers

Association, Inc. The Safety Board reiterated one recommendation to the State of Wisconsin.

The National Transportation Safety Board is an independent Federal agency dedicated to

promoting aviation, railroad, highway, marine, pipeline, and hazardous materials safety. Established

in 1967, the agency is mandated by Congress through the Independent Safety Board Act of 1974 to

investigate transportation accidents, determine the probable causes of the accidents, issue safety

recommendations, study transportation safety issues, and evaluate the safety effectiveness of

government agencies involved in transportation. The Safety Board makes public its actions and

decisions through accident reports, safety studies, special investigation reports, safety

recommendations, and statistical reviews.

Recent publications are available in their entirety on the Web at http://www.ntsb.gov/. Other

information about available publications may be obtained from the Web site or by contacting:

National Transportation Safety Board

Public Inquiries Section, RE-51

490 L’Enfant Plaza, S.W.

Washington, D.C. 20594

(202) 314-6551

Safety Board publications may be purchased, by individual copy or by subscription, from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(703) 605-6000
	


	






HIGHWAY ACCIDENT REPORT

Adopted: July 24, 1998

Notation 6832B



	




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iii

CONTENTS

EXECUTIVE SUMMARY.........................................................................................................vii

INVESTIGATION ........................................................................................................................ 1

The Accident ................................................................................................................................... 1

Event Sequence ........................................................................................................................ 1

Doubles Truck................................................................................................................... 1

Flatbed Truck.................................................................................................................... 5

Passenger Van................................................................................................................... 5

Refrigerator Truck ............................................................................................................ 5

Witness Accounts ............................................................................................................. 6

Emergency Response ............................................................................................................... 7

Injuries........................................................................................................................................... 10

Damage.......................................................................................................................................... 10

Vehicle Information ...................................................................................................................... 10

Doubles Truck........................................................................................................................ 10

Flatbed Truck ......................................................................................................................... 11

Passenger Van ........................................................................................................................ 12

Refrigerator Truck.................................................................................................................. 12

Driver Information ........................................................................................................................ 15

Doubles Truck........................................................................................................................ 15

License and Citations...................................................................................................... 15

Training and Qualifications ............................................................................................ 15

Flatbed Truck ......................................................................................................................... 18

Passenger Van ........................................................................................................................ 18

Refrigerator Truck.................................................................................................................. 18

Motor Carrier Information............................................................................................................. 18

Doubles Truck........................................................................................................................ 18

Driver Qualification File................................................................................................. 18

Doubles Training ............................................................................................................ 19

Role of Safety in the Corporate Structure....................................................................... 19

Flatbed Truck ......................................................................................................................... 20

Passenger Van Rental Contract.............................................................................................. 20

Refrigerator Truck.................................................................................................................. 20

Motor Carrier Oversight................................................................................................................ 20

Doubles Truck........................................................................................................................ 20

Flatbed Truck ......................................................................................................................... 20

Refrigerator Truck.................................................................................................................. 20

Highway Information .................................................................................................................... 21

Physical Evidence .................................................................................................................. 21

Traffic Volumes and Speeds .................................................................................................. 22
iv

Accident Statistics.................................................................................................................. 22

Adverse Weather Countermeasures ....................................................................................... 24

Wisconsin Department of Transportation Maintenance Manual .................................... 26

Road Weather Information System................................................................................. 26

Other States..................................................................................................................... 27

Recent Research.............................................................................................................. 27

Research in Wisconsin.................................................................................................... 28

Nationwide Standards ..................................................................................................... 28

Large Truck Crashes .............................................................................................................. 28

Medians.................................................................................................................................. 29

Widths............................................................................................................................. 30

Barriers............................................................................................................................ 30

Cross-median Accident Coding ...................................................................................... 30

Toxicological Tests ....................................................................................................................... 31

Results.................................................................................................................................... 31

Timeliness .............................................................................................................................. 32

Survival Aspects............................................................................................................................ 32

Restraint Use.......................................................................................................................... 32

Wisconsin Seat Belt Use Law................................................................................................ 34

Emergency Operations Plan................................................................................................... 34

Tests and Research ........................................................................................................................ 34

Doubles Truck ECM .............................................................................................................. 34

Passenger Van ECM .............................................................................................................. 34

Passenger Van Restraint Systems .......................................................................................... 35

Doubles Truck Road Test ...................................................................................................... 35

Other Information.......................................................................................................................... 35

Vehicle Underride .................................................................................................................. 35

Vehicle Conspicuity............................................................................................................... 35

Phase 4 Computer Simulation................................................................................................ 35

Heavy Truck Simulators ........................................................................................................ 36

ANALYSIS................................................................................................................................... 37

General .......................................................................................................................................... 37

The Accident ................................................................................................................................. 37

Wind....................................................................................................................................... 37

Roadway Surface Conditions................................................................................................. 37

Speed of the Doubles Truck................................................................................................... 38

Doubles Truckdriver’s Initial Loss of Control....................................................................... 39

Doubles Jackknife.................................................................................................................. 39

Collision of the Doubles Truck and the Flatbed Truck.......................................................... 40

Collision of the Flatbed Truck and the Passenger Van .......................................................... 40

Collision of the Refrigerator Truck and the Flatbed Truck.................................................... 40
v

Driver Countermeasures................................................................................................................ 42

Judgment of the Doubles Driver ............................................................................................ 42

Training and Experience ........................................................................................................ 42

Corporate Culture................................................................................................................... 43

Vehicle Countermeasures.............................................................................................................. 43

Stability of Doubles................................................................................................................ 43

Traction Control..................................................................................................................... 44

Highway Countermeasures............................................................................................................ 45

Adverse Weather.................................................................................................................... 45

Median Barriers...................................................................................................................... 46

Reporting of Cross-median Accidents ................................................................................... 46

Survivability Countermeasures ..................................................................................................... 47

Crash Forces........................................................................................................................... 47

On-board Recorders........................................................................................................ 48

Occupant Injuries and Seat Belt Use...................................................................................... 48

Wisconsin Seat Belt Use Law................................................................................................ 50

Emergency Response..................................................................................................................... 50

CONCLUSIONS ......................................................................................................................... 52

Findings......................................................................................................................................... 52

Probable Cause.............................................................................................................................. 52

RECOMMENDATIONS............................................................................................................ 53

APPENDIX A -- Investigation and Hearing ................................................................................ 57

APPENDIX B -- Injury Information ............................................................................................ 59

APPENDIX C -- Roadway Weather Information System............................................................ 61

APPENDIX D -- Median Barrier Warrants.................................................................................. 63

APPENDIX E -- Safety Board Phase 4 Computer Runs.............................................................. 65

APPENDIX F -- Safety Board Recommendations on Mandatory Seat Belt Use Laws............... 67

ACRONYMS AND ABBREVIATIONS ................................................................................... 70

vii

About 5:52 a.m. on February 12, 1997, a

doubles truck with empty trailers, operated by

Consolidated Freightways, Inc., that was

traveling northbound on U.S. Route 41, a fourlane divided limited access highway near

Slinger, Wisconsin, lost control and crossed

over the 50-foot depressed median into the

southbound lanes. A flatbed truck loaded with

lumber, operated by McFaul Transport, Inc.,

that was traveling southbound on U.S. Route 41

collided with the doubles truck, lost control, and

crossed over the median into the northbound

lanes. A northbound passenger van with nine

adult occupants struck and underrode the right

front side of the flatbed truck at the landing

gear. A refrigerator truck loaded with produce,

operated by Glandt/Dahlke, Inc., that was also

traveling northbound, struck the right rear side

of the flatbed truck. Although it had snowed

from about 8 p.m. to 3 a.m. the night before, it

was clear at the time of the accident. Other

motorists and the emergency responders to the

accident scene reported icy patches in the

roadway. Eight of the nine van occupants

suffered fatal injuries, and the remaining

occupant suffered serious injuries. Two of the

three commercial truckdrivers were treated for

minor injuries and released; the third refused

treatment.

The National Transportation Safety Board

determines that the probable cause of the

accident was the doubles truckdriver’s lack of

judgment in driving too fast for the

configuration of his truck under the hazardous

highway weather conditions. Contributing to the

severity of the injuries and the reduced

potentiality for survival was the lack of restraint

use by the unrestrained occupants of the

passenger van.

The major safety issues identified in this

accident are:

• Judgment and experience of the

doubles truckdriver;

• Stability of doubles trucks;

• Effectiveness of snow and ice

removal;

• Adequacy of the American

Association of State Highway and

Transportation Officials divided

freeway median barrier warrants;

• Adequacy of the States’ accident

report forms to capture crossmedian accident data; and,

• Availability and use of restraints.

As a result of this accident investigation, the

Safety Board makes recommendations to the

Federal Highway Administration, the National

Highway Traffic Safety Administration, the

National Association of Governors’ Highway

Safety Representatives, the American Trucking

Associations, the Motor Freight Carrier

Association, the International Brotherhood of

Teamsters, the American Association of State

Highway and Transportation Officials, the

Wisconsin Department of Transportation, the

Independent Truckers and Drivers Association,

the National Private Truck Council, and the

Owner-Operators Independent Drivers Association, Inc. Also, the Safety Board reiterates one

recommendation to the State of Wisconsin.

EXECUTIVE SUMMARY

The Accident

About 5:52 a.m.

1

 on February 12, 1997, a

doubles truck with empty trailers,2

 operated by

Consolidated Freightways, Inc., (CF)3

 that was

traveling northbound on U.S. Route 41 (US 41),

a four-lane divided limited access highway, near

Slinger, Wisconsin, lost control and crossed

over the 50-foot depressed median into the

southbound lanes. A flatbed truck loaded with

lumber, operated by McFaul Transport, Inc.,

that was traveling southbound on US 41 collided

with the doubles truck, lost control, and crossed

over the median into the northbound lanes. A

northbound passenger van with nine adult

occupants struck and underrode the right front

side of the flatbed truck at the landing gear.4

 A

refrigerator truck loaded with produce, operated

by Glandt/Dahlke, Inc., also traveling

northbound, struck the right rear side of the

flatbed truck. Figure 1 represents several major

events in the accident sequence: (1) the doubles

truck’s loss of control and median crossover, (2)

the doubles truck and flatbed collision, (3) the

flatbed truck’s loss of control and median

crossover, (4) the collision of the blue passenger

van and the refrigerator truck with the flatbed

truck. See figure 2 for a photo showing the

accident aftermath.

Although it had snowed from about 8 p.m.

to 3 a.m. the night before, it was clear at the

time of the accident. Other motorists and the

emergency responders to the accident scene

reported icy patches in the roadway.

 

1

Times are given in central standard time.

2

For the purposes of this report, the tractor/double

semitrailer combination unit will be referred to as the

“doubles truck,” the tractor/flatbed semitrailer combination

unit as the “flatbed truck,” and the straight refrigerator

truck as the “refrigerator truck.”

3

See the last page for a list of all acronyms and

abbreviations used in this report.

4

The landing gear on a semitrailer is a device that

provides support for the trailer when it is not connected to

the tractor.

Eight of the nine van occupants suffered

fatal injuries, and the remaining occupant

suffered serious injuries. Two of the three

commercial truckdrivers were treated for minor

injuries and released; the third refused

treatment.

Event Sequence -- On the evening before

the accident, it began to snow about 8 p.m. The

Washington County, Wisconsin, road

maintenance crew began plowing the roadway

and salting the ramps on US 41 between 10 and

10:30 p.m. Although the snow stopped between

2 and 3 a.m. on the morning of the accident, the

road crew continued to conduct snow and ice

removal because of blowing snow and the

freezing temperatures. About 3:45 a.m., they

noticed “black ice”5

 forming on the roadway and

began applying salt with a wetting agent. By

5:15 a.m., the area of US 41 near the

intersection of County Trunk Highway K

(CTH K) had received two applications of salt

and wetting agent.

The following are the surviving drivers’ and

witnesses’ accounts of what happened during

this accident. The accident involved four

vehicles — the doubles truck, the flatbed truck,

the passenger van, and the refrigerator truck (see

figure 3) — and three collisions that occurred at

two different locations.

Doubles Truck -- According to the doubles

driver, he went to bed at 7 p.m. on the evening

before the accident. The CF dispatcher called

him at 12:30 a.m. to alert him that he would be

needed later that morning. He returned to bed at

1 a.m. and slept until he awoke at 3:30 a.m.,

when he got up and reported to work at

4:30 a.m. He left the CF Milwaukee, Wisconsin,

terminal at 5 a.m. to deliver a pair of empty

trailers to Menasha, Wisconsin, about 100 miles

to the north. The trip was routine and no

deadline for delivery was specified.

 

5

Black ice is a very thin coating of clear, bubble-free,

and homogeneous ice, which forms on roadway pavements

under certain temperature conditions.

INVESTIGATION
2

Figure 1 -- Accident events

Doubles Truck

Blue Passenger Van

Entrance Ramp

From CTH-K

Refrigerator Truck

Vicinity of Doubles Truck

and Flatbed C ollision

Possible Path of Flatbed

Loss of Control

(3)

Southbound

Flatbed Truck

(2)

Refrigerator Truck with

Blue Passenger Van and

Vicinity of Collision of

Flatbed Truck

Flatbed Truck

(4)

Exit Ramp

to CTH-K

Approximate Scale

in Feet

0 5' 10' 20' 40'

Vicinity of D oubles Truck

US Highway 41

Loss of Control

Northbound

(1)

N

E

S

W
3

Figure 2 -- Aftermath of the accident
4

Figure 3 -- Configuration of four accident vehicles

Flatbed Truck

Overhead View of Doubles Truck

Doubles Truck

Passenger Van Refrigerator Truck
5

The doubles driver indicated in several

interviews6

 that the “roads in Milwaukee were

wet” and became icy “a couple of miles north of

the split.” US 41 and U.S. Route 45 diverge

approximately 8 miles south of the accident site.

The doubles driver initially indicated to

police that his trailers slipped at least three

times en route, so he switched to a lower (4th )

gear. He later told Safety Board investigators

that about 15 miles out of the CF yard, he was

traveling about 50 to 55 mph in 7th gear and felt

the trailer do a slight fishtail, which indicated to

him that the roads were not in good condition.

He stated that at some time while he was

traveling further north, snow was blowing

across the road from the west when he felt the

trailer do a second fishtail. He said that at that

point, he reduced his speed from about 50 to

55 mph to about 35 to 40 mph. He did not know

where this location was relative to the accident

site.

The doubles driver told the Safety Board

investigators that no traffic was in his immediate

vicinity when he lost complete control. He said

he was traveling between 30 and 35 mph in 6th

gear. He had just checked his mirrors when he

suddenly felt the trailers slip on the icy

roadway. He said when the trailers “pushed

forward and towards the right,” he “immediately

let off the accelerator.” He indicated that he was

neither shifting gears at the time nor did he

apply his brakes. He also indicated that he had

no time to react to the developing situation, and

he attempted to countersteer the tractor.

The doubles driver said that just after the

truck slipped, he noticed several cars traveling

southbound and the lights of a [southbound]

tractor/semitrailer. His vehicle was still moving

in a circular motion when his face hit the dash

or steering wheel. He sensed that he had been

stopped for 30 to 60 seconds when he felt

another impact.

Flatbed Truck -- About 4:15 a.m. on the

morning of the accident, the flatbed truck

 

6

This driver gave two statements to the police on the

day of the accident and was later interviewed by Safety

Board investigators on March 14 and October 20, 1997,

with counsel present.

loaded with lumber left the McFaul Transport,

Inc., (MTI) yard in New London, Wisconsin.

The flatbed truckdriver told Safety Board

investigators7

 that about 5:45 a.m., he was

southbound on US 41 traveling about 55 mph

when he observed a truck in the median. At the

time, he wondered why the truck was making an

illegal U-turn.

After observing the truck for a moment, he

realized it was not turning around but had lost

control. He recalled seeing a lot of snow

swirling around the moving vehicle. He told the

police8

 that he was “trying to avoid the

northbound truck and went off towards the right

shoulder” and the truck hit him “on the driver’s

side.” He continued moving in the right lane but

lost control and crossed over the left lane and

median into the northbound lanes. He

remembered seeing a lot of snow swirling

around him and also seeing headlights; he then

recalled coming to a complete stop.

Passenger Van -- About 5:15 a.m., nine adults

left Milwaukee, heading north for an annual ice

fishing trip. The group had rented a blue

15-passenger van from May Fair Rent A Car,

Inc., for the trip. The sole survivor in the van,

who had been seated in the middle of the van’s

fourth row, told Safety Board investigators that

the road was wet when they departed

Milwaukee, and that it had snowed earlier that

morning. He said that immediately before the

van struck the trailer of the flatbed truck,

everything in the van was quiet.

Refrigerator Truck -- About 5:10 a.m., a

refrigerator truck with a load of produce and

dairy products left the Glandt/Dahlke, Inc., yard,

in Milwaukee. The driver told Safety Board

investigators that he stopped in Richfield,

Wisconsin, about 5:35 or 5:40 a.m. to make a

delivery.9

 He indicated that when he left

Richfield, the roads were intermittently icy, the

wind seemed to be coming from the west or

 

7

The flatbed truckdriver was interviewed by Safety

Board investigators on March 14, 1997.

8

The flatbed truckdriver gave a statement to the police

on the day of the accident.

9

The refrigerator truckdriver was interviewed by

Safety Board investigators on March 13, 1997.
6

northwest, the visibility was clear, and it was

dark.

The refrigerator truckdriver said that he was

traveling in the right lane at 50 to 55 mph when

he noticed a van 6 to 8 vehicle lengths ahead of

him. He indicated that he saw a dark object

enveloped in swirling snow moving at him from

the median at about a 45° angle. He recalled

thinking about whether he should turn to the left

or the right to avoid hitting it when he noticed a

brief illumination of the van’s brake lights

before it collided with the trailer. He said that

when the van hit the trailer, the trailer was

sliding and wood was flying from it. He

slammed on his brakes, swerved to the left, and

hit the end of the trailer, which moved in

response to the impact. His truck came to rest in

the median.

Witness Accounts -- Several witnesses

observed the doubles truck as it traveled

northbound on US 41. One witness, a

tractor/semitrailer driver,10 was following the

blue passenger van and was subsequently passed

by the doubles and refrigerator trucks. He

indicated that a light wind was blowing from the

west and, although it was not strong enough to

affect his truck, the wind was blowing snow

across the road. He said that the right lane

appeared wet, with more swirling snow in the

left lane.

He stated that he was traveling in the right

lane at 50 to 55 mph [the speed limit was 65

mph] because of the weather and road

conditions. The blue passenger van was ahead

of him traveling at roughly the same speed. Just

south of the State Trunk Highway 144 overpass

(2 miles south of the accident site), he noticed a

set of headlights behind him that was “wavering

 

10The Washington County Sheriff’s Department

interviewed this witness on the day of the accident. He

gave them a written statement on February 13, 1997, and

they reinterviewed him on March 5, 1997. A Safety Board

investigator interviewed him on June 3, 1997. This witness

has a commercial driver’s license with hazardous materials,

tank trailer, and double and triple trailer endorsements. He

has been driving tractor/semitrailers for 10 years with some

doubles experience. He was familiar with the route, as he

drove US 41 professionally once or twice a week and

occasionally drove it privately. On the day of the accident,

he was driving a conventional tractor with a 42-foot trailer;

the total vehicle weight was 60,000 to 65,000 pounds.

from side to side.” He thought the headlights

might belong to a doubles truck because

tractor/trailer headlights normally appear to

bounce up and down. When the passing truck

had reached the midpoint of his trailer, he saw

that it was a doubles truck, and he started to

slow so the truck could pass more quickly. He

slowed to 45 mph and estimated that the passing

truck was traveling in excess of 60 mph.

As the doubles truck passed him, the

witness noticed the rear trailer swaying back and

forth about 6 inches in an even, continuous

manner. He stated that, from the way the trailers

were behaving, it appeared to him either that

they were empty or that the rear trailer was

heavier than the front. He said he flashed his

headlights to signal the doubles truck that it was

clear to move into the right lane, but the doubles

truck stayed in the left lane until he could no

longer see it. He also saw the doubles truck pass

the blue passenger van. Then, both the doubles

truck and the passenger van disappeared from

his view.

After the doubles truck had passed him and

he was in the vicinity of Arthur Road (1.3 miles

south of the accident site), the witness said he

accelerated, but the acceleration was slow due to

a slight upgrade and the weight of his truck.

When he reached about 50 mph, he noticed a

cloud of smoke coming from the median ahead

of him. A few seconds later, he saw another

cloud, also in the median but closer and moving

towards him. He did not see any lights in this

cloud. He said that, as he slowed, he saw the

headlights of the vehicle behind him [the

refrigerator truck] move into the left lane to pass

him. He started to move towards the shoulder

and noticed the on-ramp for CTH K. He headed

for the ramp.

He heard a crash, saw a white tractor with a

flatbed trailer, and saw that a blue van had hit

the trailer. He stated that although he heard the

collision, he did not see it, nor did he see any

brake lights on the blue passenger van at any

time. As he was slowing to a stop on the ramp,

he saw the refrigerator truck attempt to avoid

the flatbed trailer. He said the “rear axles of the

straight truck were off the ground at impact.” He

reached for his cell phone, heard another noise,

looked up, and saw another van driving across

the lumber that had been knocked off the
7

flatbed. He then called 911 and reported the

accident.

Another northbound truckdriver stated that

the doubles truck had passed him just outside

Milwaukee at State Trunk Highway 145. This

witness indicated that he was traveling

approximately 47 to 49 mph, and it took almost

a mile for the doubles truck to pass him. (See

figures 4 and 5 for maps showing the accident

area and important reference points.)

Emergency Response -- The first witness

notified the Washington County Sheriff’s

Department (WCSD) dispatch of the collision at

5:53 a.m. by cellular phone. Emergency

Medical Service (EMS) units were dispatched at

5:54 a.m. (See table 1 for a timeline of the

emergency response.) Two units from the

Slinger Police Department, the first emergency

personnel on scene, arrived at 5:56 a.m. They

were followed by the Slinger Fire Department

(SFD) command vehicle, which arrived at 6:02

a.m. The Incident Commander established the

command post near the blue passenger van,

aboard the SFD command vehicle, which had

communications equipment. Two other

firefighters aboard the command vehicle

conducted an initial reconnaissance of the

accident scene and reported back to the Incident

Commander. Several emergency vehicles

arrived after the SFD command vehicle.

Seventeen WCSD officers, seven Wisconsin

State troopers, seven fire departments, one

private ambulance service, and one Flight for

Life helicopter responded to the accident. Two

additional helicopters were dispatched to the

scene but were turned back because they were

not needed. Four patients were transported;

three by ambulance to local hospitals and one by

helicopter to a trauma center in Milwaukee. One

victim from the van was not transported to a

trauma center until 2 hours and 8 minutes after

the notification, because on-scene medical

personnel decided to stabilize the patient before

transporting him. The north- and southbound

lanes of US 41 were reopened by 2:03 p.m.

(8 hours and 10 minutes after the accident).

Table 1 -- Emergency response

*Times are based on the 24-hour clock (for example, 1403 is 2:03 p.m.).

Time* Time from initial

notification

Action

0553 00:00 Initial 911 call received by WCSD dispatch

0554 00:01 EMS dispatched

0556 00:03 Two Slinger Police Department units arrived on scene

0602 00:09 SFD command vehicle arrived on scene

0607 00:14 First EMS unit arrived

0619 00:26 Flight for Life dispatched from Milwaukee

0638 00:45 Flight for Life arrived on scene

0652 00:59 Ambulance delivered first van victim to area hospital

0801 02:08 Flight for Life helicopter delivered second van victim to

trauma center

1228 06:35 Northbound lanes of US 41 reopened

1403 08:10 Southbound lanes of US 41 reopened; area cleared
8

Figure 4 -- General accident area and reference points
9

Figure 5 -- Immediate vicinity of Slinger accident
10

Injuries

The doubles and flatbed truckdrivers were

treated for minor injuries and released that day

from local hospitals. The refrigerator truckdriver

refused treatment. Table 2 is based on the injury

criteria11 of the International Civil Aviation

Organization, which the Safety Board uses in

accident reports for all transportation modes.

(See appendix B for an injury table based on the

Abbreviated Injury Scale of the Association for

the Advancement of Automotive Medicine.)

Damage

The doubles truck tractor was a total loss.

The front of the doubles lead trailer and the top

of the rear trailer both had moderate damage. The

single-axle converter dolly was not damaged. The

flatbed truck tractor was also a total loss, and the

semitrailer sustained major damage. The

passenger van was a total loss. It sustained major

damage to the front, with intrusion into the

driver’s and front passenger’s spaces. Damage to

the refrigerator truck was limited to the front

bumper grille and hood assembly.

 

11Title 49 Code of Federal Regulations (CFR) 830.2

defines fatal injury as “Any injury which results in death

within 30 days of the accident.” It defines serious injury as

an injury that: “(1) Requires hospitalization for more than

48 hours, commencing within 7 days from the date the

injury was received; (2) results in a fracture of any bone

(except simple fractures of fingers, toes, or nose); (3)

causes severe hemorrhages, nerve, or tendon damage; (4)

involves any internal organ; or (5) involves second or third

degree burns, or any burn affecting more than 5 percent of

the body surface.”

Vehicle Information

Doubles Truck -- The doubles truck, a

tractor/double semitrailer combination unit,

consisted of a conventional 1993 Freightliner

two-axle tractor, a 1992 Road Systems, Inc., 28-

foot single-axle box trailer, a 1985 Road

Systems, Inc., single-axle converter dolly, and a

1989 Road Systems, Inc., 28-foot single-axle box

trailer. The overall length of the combination unit

was 72.5 feet; it had a calculated gross vehicle

weight of 33,000 pounds. This tractor/double or

twin semitrailer configuration is commonly

referred to as a western double or a doublebottom.

The tractor was equipped with a Cummins

diesel engine with an electronic control module

(ECM), an Eaton-Fuller 7-speed manual

transmission, and cruise control. The Rockwell

RS-23-185 rear-drive axle had a 3.42 gear ratio.

The front axle had type 9 wedge12 brakes and

ribbed tread tires. The rear axle had dual (two

per wheel) type 12 wedge brakes with type 16

spring brakes and traction tread tires.

 

12With wedge brakes, the brake power unit, in either

air or hydraulic chambers, “forces a wedge between two

rollers and two plungers, which causes the plungers to

spread apart and push the brake shoes against the drum.”

Source: Rockwell Stopmaster Brakes, Field Maintenance

Manual, 4R, revised October 1979.

TYPE

Doubles

Truck

Driver

Flatbed

Truck

Driver

Van

Driver

Van

Passengers

Refrigerator

Truck

Driver

TOTAL

Fatal -- -- 1 7 -- 8

Serious -- -- -- 1 -- 1

Minor 1 1 -- -- -- 2

None -- -- -- -- 1 1

Total 1 1 1 8 1 12

Table 2 -- Injuries
11

According to the engine manufacturer, on a

level roadway, the doubles truck could achieve a

maximum speed of 26.5 mph in 4th gear, 36.4

mph in 5th gear, 49.4 mph in 6th gear, and 66.2

mph in 7 th gear, all based upon 1,800

rpm.

13 Because of the setting of the vehicle speed

sensor (governor), the vehicle would not

ordinarily (except when traveling on a

downgrade) exceed 62 mph in 7th gear or 47

mph in 6th gear, both at 1,700 rpm. The tractor

was equipped with a “governor override,” which,

under certain conditions, temporarily permits the

engine to overspeed by about 10 percent above

the 1,800 rpm programmed into the ECM.

The empty trailers were similarly equipped

with wedge brakes and ribbed tread tires, and

both weighed about 7,380 pounds with gross

vehicle weight ratings (GVWRs) of 40,000

pounds. The converter dolly was equipped with

type 9 wedge brakes and highway tread tires. The

unloaded dolly weighed 2,850 pounds.

The on-scene examination of the tractor,

which included the brake, steering and

suspension systems, tires, fifth wheel, and cab

controls, found no safety defects. A later

examination14 of the steering box and

components found no preimpact defects or

damage. The on-scene examination of the two

trailers and the A-dolly found no defects.

The tractor sustained damage to the right

side and left rear corner of the cab. The rear

chassis was skewed to the right, and the rightdrive dual-axle wheel had been moved forward.

The floorboard section over the transmission

had been moved forward. The rear edge of the

opening for the gear-shift lever was found tight

against the lever arm. The shift lever arm was

found in 6th gear. The right side of the cab’s

 

13The Cummins Engine Company computer

simulation program is capable of calculating vehicle

speeds within each gear. In this instance, the parameters

(vehicle weights, transmission type, axle ratio, and engine

type) were furnished to the Cummins Engine Company by

Safety Board investigators.

14The examination took place at the CF Milwaukee

facility and was performed by a representative of TRW,

the manufacturer, on April 28, 1997. Representatives from

the Safety Board, the Wisconsin State Highway Patrol, the

Freightliner Corporation, and CF participated in the

examination.

front hood and fender assembly had contact

damage. The front axle was dislodged and the

right front bumper end, outboard of the chassis,

was bent forward 90°.

The lead trailer sustained damage to the front

bulkhead and left front cornerpost area. The Adolly did not appear to be damaged. The rear

trailer had damage to the top of the right center

front bulkhead and roof edge.

Flatbed Truck -- The flatbed truck, a

tractor/flatbed semitrailer combination unit, was

composed of a 1993 Mack conventional threeaxle tractor and a 1992 Fruehauf tandem-axle

45-foot flatbed semitrailer. The overall length of

this combination vehicle was about 60 feet, and

the calculated gross weight was about 76,675

pounds.

The on-scene examination of the tractor’s

brakes, steering and suspension systems, tires,

fifth wheel, and cab controls found no defects.

The examination of the trailer’s brake system,

suspension, tires, and 5th wheel plate revealed no

defects. During the postaccident towing

operations, the rear axle brakes had been “backed

off,” which precluded a determination of the

precollision pushrod position.

The flatbed tractor sustained major damage,

mainly to the left side. The bumper extension and

lower front fairing were dislodged. The fender

and left side of the hood were dislodged. The

front axle was displaced rearward. The left side

of the windshield was fractured. The left side

rearview mirror was torn away from the door.

The left side fuel tank was damaged but had not

ruptured. The left side chassis-mount toolbox

was damaged. Both of the left outside rear-dual

wheels and tires were damaged.

The trailer had impact damage along the left

rub rail about 10 feet to the rear of the header

board. The left front tandem wheel was damaged,

and the suspension was fractured. The right

landing gear leg was damaged and pushed under

the trailer mainframe rail. The red paint on the

leg bore clean scrape marks through the coating

of spray from snow, slush, and road salt. The

right front tandem axle had damage to the outer

wheel, and the suspension was separated.
12

Passenger Van -- The passenger van was a

1997 Dodge Ram 3500 Maxi-wagon. The van

was equipped with a 5.9L magnum V-8 gasoline

engine, a 4-speed automatic transmission, and

rear-wheel drive. It was also equipped with an

antilock braking system with disk brakes on the

front and drum brakes on the rear axles.

The van was designed to seat 15 passengers.

As shown in figure 6, the van had five rows of

seats. The first row had bucket seats for the

driver and the right front passenger; both seats

were equipped with lap/shoulder belts. The

driver-side restraint system was equipped with a

supplemental airbag and a pre-tensioner for the

belt.

Rows 2 through 4 were bench seats with

three seating positions each. These seats were

designed so they could be removed. The left

outboard seating position in each of these bench

seats was equipped with a lap/shoulder belt,

while the center and right outboard seating

positions were equipped with lap belts only.

Row 5, which was also a bench seat, differed

from the other rear rows in that it was not

designed for easy removal and had four seating

positions. The left and right outboard seating

positions were equipped with lap/shoulder belts.

The two inboard positions were equipped with

lap belts only. As shown in figure 6, rows 2 and

3 in the accident van were removed in accordance

with the rental agreement. The rented

configuration had nine seating positions, five

with lap/shoulder belts and four with lap belts

only.

A complete examination of the passenger van

could not be made because of the extensive front

end damage. All the front brake pads and rear

shoes appeared to be almost new and showed

very little wear. The tires showed very little tread

wear. The master cylinder was damaged, and the

damage to the front end precluded examination of

the steering components. No defects were found

in the limited examination.

The front of the van, where the driver and the

right front passenger were seated, showed

extensive intrusion and loss of survivable space.

The amount of intrusion varied across the width

of the van, from about 29 inches15 on the left side

to about 52 inches on the right side. The rear of

the van, where seat rows 4 and 5 were located,

showed no intrusion or loss of survival space.

(See figure 7.)

The front bumper was pushed up and aft and

showed evidence of direct contact with a rear

wheel of the tractor and the landing gear of the

trailer. The front wheels were displaced

rearward. The grille, hood, headlamp area,

radiator, and engine front had major impact

damage and red paint transfers. Shearing-type

impact damage affected the entire upper area of

the van from across the top of the cowl/dash at

the windshield opening to each A-pillar and from

the front doors and the roof panel extending

rearward to the driver area and the passenger

seatbacks.

Refrigerator Truck -- The refrigerator truck

was a 1992 two-axle, straight “box” truck

equipped with a refrigerator unit. It was powered

by a Ford diesel engine and equipped with a 6-

speed manual transmission. The wheel base was

227 inches and the overall length was 31.5 feet.

The loaded weight at the time of the accident was

approximately 20,290 pounds and the GVWR

was 33,000 pounds.

The on-scene examination of the refrigerator

truck included the brake, steering, and suspension

systems; the tires; and the cab controls. One of

the automatic slack adjusters was found to be out

of adjustment and a second one was found to be

in need of adjustment. No other defects were

found.

The damage to the refrigerator truck was

limited to the truck front. The top right chassis

rail end, at the bumper attach bracket, had a

clean deep indent, and the steel bumper face had

two curved line impressions with the same radii

as the flatbed trailer tandem wheels. The right

fender, headlamp assembly, and grille were

damaged. The suspension system, front axle,

engine, and drive line were not damaged.

 

15Measured from the precollision location of the base

of the A-pillar, the forward-most roof support.
13

Figure 6 -- Passenger van seating and restraint availability

Row 1

(Bucket Seats)

Row 2

(Bench Seat)

Row 3

(Bench Seat)

Row 4

(Bench Seat)

Row 5

(Bench Seat)

*

**

* Airbag

** Manual lap/shoulder belt with pre-tensioner

S manual lap/shoulder continuous loop

L Lap belt only

Van Seating Availability from Factory

Row 1

(Bucket Seats)

Row 4

(Bench Seat)

Row 5

(Bench Seat)

*

**

* Airbag

** Manual lap/shoulder belt with pre-tensioner

S manual lap/shoulder continuous loop

L Lap belt only

Van Seating Availability Accident Vehicle

Rows 2 and 3 

removed per rental reservation

S S

SLL

S LL S

SLL

SLL

*

** S S

S LL S

SLL
14

Center of front bumper

-post collision

Intrusion into occupant

space left side

Intrusion into occupant

space right side

flatbed trailer

(@J

o

IL*’I

Figure 7-- Van and flatbed intrusion profile
15

Driver Information

Doubles Truck -- The doubles driver was

33 years old and had a valid Wisconsin State

commercial driver’s license (CDL). During

interviews with Safety Board personnel, the

driver indicated that he had been adequately

rested in the 72 hours before the accident. At the

time of the accident, he had been awake for 2

hours, 15 minutes, and had been driving the

doubles truck for about 45 minutes.

License and Citations -- The license had a

doubles/triples endorsement and an expiration

date of October 29, 1998. The driver also held a

valid medical examiner’s certificate with an

expiration date of October 17, 1998. A check

with the National Driver Register (referred to as

the NDR) database showed no adverse records.

Local checks of his record found:

• 1/11/97 - accident in personal

vehicle, citation for running a red

light in Milwaukee;

• 9/24/96 - speeding conviction on

CDL (40 mph in a 25 mph zone) in

Ripon, Wisconsin;

• 8/28/95 - speeding (70 mph in a 55

mph zone);

• 7/8/93 - speeding in Iowa on CDL

(no record in Iowa);

• 6/25/93 - speeding (71 mph in a 55

mph zone), dismissed after trial;

• 9/21/89 - motorcycle accident, cited

for following too close and not

having a motorcycle endorsement on

his license; and,

• 7/31/88 - speeding conviction.

Training and Qualifications -- The doubles

driver had been employed by CF since October

24, 1996. He took a written knowledge test and a

road test on October 11, 1996, as part of the

company’s new-hire procedures. Table 3 lists the

driver’s previous employment and driving

history.

Table 3 -- Doubles driver employment and driving history

*Note: Discrepancies appear in the information provided on the driver’s different job applications, in his

interview, and by his attorney.

DATES* COMPANY* EXPERIENCE/POSITION*

10/24/96 - 02/12/97 Consolidated Freightways Doubles driver (16 hours a

week)

01/31/96 - 10/22/96 American Transport Tractor-trailer driver

10/20/95 - 12/29/95 United Parcel Service Doubles driver

07/95 - 10/95 Roadway Package

Systems

Driver

03/95 - 10/95 Federal Express Package handler,

dockworker, tractor-trailer

driver

04/20/94 - 10/6/95 Tandem Transport (JDC

Trucking)

Tractor-trailer driver

06/24/93 - 04/15/94 Custom Cuts, Inc. Over-the-road tractor-trailer

driver

01/04/93 - 01/28/93 Pro-Drive Truck Driving

School

Student
16

The doubles driver told the police that he had

driven the accident route five times. In an

October 20, 1997, interview with Safety Board

personnel, the driver indicated that he had never

driven the accident route with two empty trailers.

The carrier later informed the Safety Board16 that

4 days before the accident, the doubles driver

drove empty doubles from Sheboygan,

Wisconsin, to Menasha, Wisconsin, without

incident. The doubles driver told the police that

he drove 16 hours a week and that CF “calls me

when they need me.” His experience at United

Parcel Service (UPS), coupled with his

experience at CF, gave him a maximum of 6

months’ experience driving doubles.

On the day of the accident, the police asked

the doubles driver, “How did you know that the

road was slippery?” He replied, “I could feel the

truck slide.”

The police asked, “Were you concerned and

how many times did the truck slide prior to losing

control?” He replied, “Being empty was a big

concern. I could feel it slide at least three times

from the split to when I lost complete control.”

They asked, “Due to your experience, due to

the road conditions and two empty trailers, do

you feel that this was dangerous?” He replied, “I

didn’t think it was dangerous enough to turn

around. I slowed down and lowered to 4th gear.”

The police also asked him, “In your training,

were you ever told what maneuvers to make

when losing control, or what procedures to follow

in icy conditions?” He replied, “Pro Drive

training stress safety first, combination of skills

and instincts, if icy conditions stay off brakes,

keep in gear, maintain [control] best as possible,

feather brakes until you pull off to the side.”

 

16February 17, 1998, letter from CF concerning the

technical review of an earlier draft of this report.

 The police asked the driver for his opinion on

“What could you have done to prevent this

accident?” The driver said, “I could have pulled

off the first second I felt slide in back.”

Doubles Training -- The driver told Safety

Board investigators that in January 1993 he

attended 3 weeks of tractor-trailer training at

Pro-Drive of Racine, Wisconsin.17 He also

indicated that in 1995 he attended UPS doubles

training consisting of 2 days of seminars with

videos of doubles and adverse weather,

homework, 3 days of yard and road experience,

and pretrips in doubles. He said that at the end of

5 days, he was certified to drive doubles, which

he did daily for 9 weeks in Wisconsin and

Illinois.

An examination of UPS records revealed that

on November 6, 1995, the doubles driver

received new driver orientation. The following

items were discussed: introduction to UPS,

emergency evacuation procedures, hazard

communication, hazardous response (1 hour),

U.S. Department of Transportation (DOT)

hazardous materials training, defective

equipment, controlled substances, book control,

space and visibility, and habits. The orientation

included a skid presentation, a video on

pretrip/couple/uncouple/post-trip activities, and a

timecard review. He also took a DOT quiz. On

November 8, 9, 10, and 13, 1995, UPS personnel

observed his performance on pretrip equipment

items, coupling, backing, uncoupling and posttrip actions, engine start and engine operation,

parking, general driving and safety habits, and

multiple trailer operations.

The Safety Board examined UPS training

documents18 and found the following information

relating to skid control:

 

17This firm no longer exists.

18Training Schedule-Day 1, Skid Control Outline and

UPS Feeder, Emergency Reaction Driving, Liberty

Mutual, Hopkinton, MA, Decision Driving Notes, Skid

Control Tractor-Trailer (April 1996).
17

CDL Doubles Endorsement -- The CDL

examination consists of a general knowledge

(multiple choice) test and a driving test in a

commercial vehicle. The doubles endorsement

consists of an additional knowledge test, but it

does not require a driving test in a doubles truck.

The following are excerpts from the January

1997 Wisconsin Commercial Driver’s Manual,

Part One (general knowledge):

In the doubles endorsement section of the

manual, it recommends steering gently because of

“rearward amplification” or the “crack-the-whip

effect,” but it does not mention oscillatory sway.

Regarding handling in adverse weather, the

doubles and triples section includes the following:

Part IV. C. Recovery from rear/drive axle skid

Get off the brake

Push in the clutch

Regain rolling traction

Countersteer

Power skid

This skid does not involve braking but rather

an excessive application of power. This causes

the drive wheels to lose traction, spin and go

into sliding traction.

The action of the tractor will be the same as in

a drive axle braking skid. A jackknife will

occur unless corrected.

It can occur when leaving a stop sign/light,

climbing a grade, powering around a curve, or,

even on level, slippery roadway when power is

applied excessively.

To control it, get off the fuel and be prepared

to countersteer.

Section 2.6 Controlling Speed:

Empty trucks require greater stopping

distances, because an empty vehicle has less

traction. It can bounce and lock up its wheels,

giving much poorer braking.

You can’t steer or brake a vehicle unless you

have traction. Traction is friction between the

tires and the road. There are some road

conditions that reduce traction and call for

lower speeds.

Section 2.6 Controlling Speed (continued):

Wet roads can double stopping distances.

Reduce speed by about one third (e.g., slow

from 55 to about 35 mph) on a wet road. On

packed snow, reduce speed by half, or more. If

the surface is icy, reduce speed to a crawl and

stop driving as soon as you can safely do so.

Melting ice. Slight melting will make ice wet.

Wet ice is much more slippery than ice that is

not wet.

Black Ice. Black ice is a thin layer that is clear

enough that you can see the road underneath it.

It makes the road look wet. Anytime the

temperature is below freezing and the road

looks wet, watch out for black ice.

Hydroplaning. In some weather, water and

slush collects on the road. When this happens,

your vehicle can hydroplane. It’s like water

skiing: the tires lose their contact with the road

and have little or no traction. You can regain

control by releasing the accelerator and

pushing in the clutch. This will slow your

vehicle and let the wheels turn freely. If the

drive wheels start to skid, push in the clutch to

let them turn freely.

Section 2.10 Driving in Winter:

Slippery Surfaces. Drive slowly and smoothly

on slippery roads. If it is very slippery, you

shouldn’t drive at all. Stop at the first safe

place.
18

Flatbed Truck -- The flatbed truckdriver,

who was 53, had a valid Wisconsin State CDL

with an October 30, 2000, expiration date and a

valid medical examiner’s certificate with a

corrective lenses restriction and an expiration

date of October 13, 1997.

During interviews with Safety Board

personnel, the driver indicated that he had been

adequately rested in the 72 hours before the

accident. At the time of the accident, he had been

awake for 3 hours and had been driving for about

90 minutes.

The flatbed driver had been employed by

MTI since March 1, 1977. Although he did not

have any formal truck driving training, the

flatbed driver successfully completed a written

exam that tested his knowledge of transportation

regulations on October 14, 1987, and a road test

on November 6, 1987.

Passenger Van -- The passenger van driver,

who was 39, had a valid Wisconsin Class D

driver’s license with a glasses restriction and an

April 23, 1998, expiration date.

The van driver’s sleep history for the 72

hours before the accident was not determined. He

had been driving for about 45 minutes when

the accident occurred.

Refrigerator Truck -- The refrigerator

truckdriver, who was 39, had a valid Wisconsin

State CDL with a December 4, 1997, expiration

date. His valid medical examiner’s certificate had

an expiration date of July 10, 1998.

During interviews with Safety Board

personnel, the driver indicated that he had been

adequately rested in the 72 hours before the

accident. At the time of the accident, he had been

awake for 2 1/2 hours and had been driving for

about 42 minutes.

The refrigerator truckdriver had been

employed with Glandt/Dahlke, Inc., since March

2, 1993. He had driven for two other Milwaukee

companies during the preceding 5 years and,

before becoming a truckdriver, he had worked as

a machine operator for 4 1/2 years. He

did not have any formal truck driving training.

Motor Carrier Information

Doubles Truck -- CF, based in Menlo Park,

California, operates a network of 373 service

centers in all 50 States, Mexico, and 8 provinces

of Canada. CF has 21,000 employees and a fleet

of 40,800 trucks, tractors, and trailers, and, in

1995, earned revenues of about $2.1 billion.

Founded in 1929, CF is a full-service trucking

company, but it competes primarily in the lessthan-truckload segment of the general freight

industry. In August 1996, CF separated the lessthan-truckload portion of its business into

Consolidated Freightways Corporation of

Delaware.

The doubles driver worked out of the

Milwaukee terminal, which has about 92 drivers,

with 70 truck tractors and 300 to 400 trailers.

Driver Qualification File -- The doubles driver’s

CF qualification file contained an application for

employment dated August 9, 1996. The

company’s October 15, 1996, pre-employment

driving record check showed the following

citations, both for speeding:

• 8/28/95 - speeding [70 mph in a 55

mph zone]; and,

• 7/8/93 - speeding in Iowa on CDL.

According to his CF file, the driver had not

informed CF about the September 24, 1996,

speeding conviction on his CDL and the

January 11, 1997, accident in his personal

vehicle. Nor did these episodes appear on a

Part Two: Section Seven: Doubles and Triples

Be more careful in adverse conditions. In bad

weather, slippery conditions, and mountain

driving, you must be especially careful if you

drive double and triple bottoms. You will have

greater length and more dead axles to pull with

your drive axles than other drivers. There is

more chance for skids and loss of traction.
19

February 18, 1997, driving record abstract

obtained by the carrier from the State after the

accident.

According to CF, prospective truckdrivers

for the firm undergo a background investigation

by a private organization before they are offered

a position. The applicant’s employment history,

experience, job knowledge, and social behavior

are investigated, and the overall evaluation

contains a recommendation on whether to hire the

individual. The report issued on the doubles

driver involved in this accident recommended that

he be hired. The CF employee safety manager

said that decisions to hire truckdrivers are based

on good judgment by company personnel. He

further stated that an applicant will be rejected if

a records check reveals any of the following:

• License revoked two times in the last

10 years;

• License suspended three times in the

last 10 years; or,

• Traffic violations (moving) that

exceed a maximum of:

◊ two in the last 2 years,

◊ three in the last 3 years, or

◊ four in the last 4 years.

In addition, truckdrivers are required to

inform CF if they incur any infraction while

operating under the authority of their CDLs.

Doubles Training -- CF does not have a

training program that specifically addresses

doubles operations. Rather, CF hires drivers who

have either graduated from an acceptable driving

school or who have not less than 1 year’s

experience with comparable types of equipment.

The CF employee training manual contains a

section about safe driving tips, but it does not

address operating doubles in adverse weather.

The employee safety manager indicated that the

operation of doubles is reviewed as part of

equipment familiarization for new hires.

Role of Safety in the Corporate Structure -- CF

has 10 full-time safety managers: the senior

safety manager at corporate headquarters and 9

others who handle employee safety in 22

divisions and 330 terminals. The CF senior

safety manager reports to the director of

Employee Relations and Safety, who reports to

the executive vice president, who reports to the

chief executive officer, who reports to the

chairman of the board.

According to the director of Employee

Relations and Safety, emphasis on safety has

increased since CF’s establishment as a separate

entity in 1996. He has stated that it is CF policy

that safety is every employee’s job. The chairman

of the board has stated that he will “commit each

member of the board of directors to sponsor one

terminal and one division for improvement in

workers’ safety.” The chief executive officer has

instituted an “I Want To Hear From You”

program through which employees are

encouraged to report safety concerns directly to

him by mail. CF permits disciplinary steps,

including termination, to be taken against

supervisors who seek reprisals against employees

who use the chief executive officer’s program.

Each CF senior manager is responsible for

becoming actively involved in safety. Division

managers hold monthly safety meetings with their

respective employee safety manager, terminal

managers, supervisors, and all employees who

are not performing other duties. The director of

Employee Relations and Safety or the senior

employee safety manager also participates in

these meetings by conference call. CF told the

Safety Board that the topic for the Milwaukee

terminal’s November 21, 1996, safety meeting

was Winter Driving and Hazard Perception. The

doubles driver did not attend this meeting, during

which a video on winter driving was shown.

Driver safety is monitored primarily

through the reporting of accidents, traffic

citations, driving records, and citizen

complaints. The carrier conducts an annual

record check in the respective State where the

driver works. A complete driving history is

obtained every 2 years by CF from the State in

which the driver is licensed. On occasion, CF

safety managers may monitor a suspected

problem driver while he is driving his assigned

route, but this method is generally considered
20

impractical because of the number of drivers and

routes within a safety manager’s assigned

territory. The doubles driver was never monitored

while driving.

Flatbed Truck -- MTI, based in New

London, Wisconsin, is an interstate, for hire,

motor carrier of general freight operating in

Wisconsin, Illinois, Indiana, and Iowa. Founded

in 1994, the company employed 3 full-time

drivers and 2 office personnel, and maintained a

fleet of 3 tractor trucks, 6 flatbeds, and 10 van

semitrailers. At the time of the accident, the

flatbed was hauling lumber to be used for the

construction of wooden pallets.

Passenger Van Rental Contract -- The

passenger van was rented from May Fair Rent A

Car, Inc., located in Milwaukee. According to the

rental office records, the passenger van driver

made the reservation on January 7, 1997. The

van was to be picked up at 4:30 p.m. on

February 11, 1997, and returned by “late p.m.”

the next day. The reservation had a notation that

read “first 2 seats out.”

Refrigerator Truck -- Glandt/Dahlke, Inc., a

company based in Milwaukee, is a private carrier

of produce. Founded in 1929, the family-run

business supplies produce to restaurants within a

150-mile radius of Milwaukee. The company

employs 13 drivers, operates 13 straight trucks,

and, in 1996, accumulated 811,407 miles. Seven

of the drivers have CDLs and two operate in

interstate commerce; the others drive smaller

trucks in the local area.

Glandt/Dahlke does not perform its own

vehicle maintenance. The accident truck and two

others are leased from SIVA Truck Leasing

under a full-service lease. SIVA performs all

vehicle and file maintenance. The companyowned trucks are maintained by area dealers who

keep the maintenance records, and the company

keeps copies of the repair bills.

The company’s driver qualification file for

the refrigerator truckdriver contained a copy of

the medical examiner’s certificate and an

application for employment but did not contain

previous employment history or background

checks. Although Glandt/Dahlke conducted preemployment controlled substance tests on all

new hires, the firm did not have a written policy

about the use of controlled substances and

misuse of alcohol. Nor had it conducted random

controlled substance or alcohol testing. Federal

regulations (49 CFR 382.601) require employers

to promulgate a policy on the misuse of alcohol

and controlled substances. The regulations

further require that the employer ensure that

copies of the materials be distributed to each

driver.

Motor Carrier Oversight

Doubles Truck -- The DOT Office of Motor

Carriers (OMC) had conducted a compliance

review of CF on December 27, 1993. This review

indicated 311 recordable accidents, or an

accident rate of .46 per million miles, based on

661,991,416 miles. The overall FY 1994

accident rate for the industry was .804 per

million miles.19 The OMC fined CF for a

violation of 49 CFR 177.823 (a) “marking and

placarding of vehicles,” for which CF entered

into a settlement agreement for $4,500. The

OMC compliance review resulted in a

satisfactory rating.

Flatbed Truck -- After the accident, a check

with the Motor Carrier Management Information

System of the OMC revealed that MTI had never

been subject to a compliance review by either

Federal or State authorities. On March 11, 1997,

the OMC conducted a compliance review of

MTI.

During the compliance review, the OMC

found several violations of the motor carrier

safety regulations. The OMC provided education

and guidance to MTI through the Federal Motor

Carrier Safety Regulations and the OMC

Accident Countermeasures Program.20 MTI

corrected most of the violations before the OMC

completed the review, which resulted in a

satisfactory rating.

Refrigerator Truck -- Glandt/Dahlke, Inc.,

serves customers in several cities in Wisconsin

and in Rockford, Illinois. The owner had

previously registered the company as a private

 

19Federal Register, November 6, 1997, p. 60037.

20The Accident Countermeasures Program is a

computer database used by the OMC to provide accident

reduction countermeasures to motor carriers.
21

interstate carrier, but in 1993, he reregistered it

as an intrastate operation. According to

Wisconsin Motor Carrier Safety Assistance

Program records, in 1993, when program

personnel were planning a compliance review of

the company, they learned it was an intrastate

carrier. Consequently, compliance reviews were

not conducted.

Highway Information

The accident occurred in the north- and

southbound lanes of US 41 at milepost 67.9 in

Washington County, just south of CTH K. (Refer

to figures 4 and 5.) US 41, a principal rural

arterial, runs north from Milwaukee through

Wisconsin to Michigan and was originally

constructed in the late 1950s as a two-lane road.

Two more lanes were added in the late 1960s,

and the four-lane roadway was upgraded to

freeway standards in 1994. Before the upgrade,

the intersection of US 41 and CTH K was atgrade with stop signs on CTH K. After the

upgrade, US 41 became a limited access highway

with a diamond interchange at CTH K.

In the area of the accident, the northbound

roadway was straight with a 0.60-percent grade.

The pavement surface north and south of the

interchange was primarily asphalt, and the

interchange was concrete, beginning about 3/4

mile south of CTH K. The concrete surface was

tined with transverse grooves that run the entire

width of each lane. The roadway cross section

consisted of a 10-foot right shoulder (6-foot

asphaltic concrete), two 12-foot travel lanes, a 6-

foot left shoulder (3-foot asphaltic concrete), and

a 38-foot grass median. The total median width,

including the left shoulders, was 50 feet.

The roadway cross slope was 2 percent for

each lane. The sideslope of the depressed median

ranged from -12.5 percent (an 8:1 ratio) to -14.3

percent (a 7:1 ratio). The design plans show a

typical shoulder slope of -16.7 percent (a 6:1

ratio). The sideslope recommended for a

depressed median by the American Association

of State Highway and Transportation Officials

(AASHTO) in its 1990 publication, A Policy on

Geometric Design of Highways and Streets, is a

6:1 ratio. The pavement markings met the

requirements in the Manual on Uniform Traffic

Control Devices.

21 According to the Wisconsin

Department of Transportation (WisDOT), within

a mile of State Trunk Highway 145 (just outside

Milwaukee), US 41 has a series of vertical

curves with an approximate average grade of 2.2

percent.

Physical Evidence -- The Safety Board

documented tire marks on the pavement and in

the snow, fluid trails, and pavement scrape and

gouge marks. The WCSD had documented the

position of the vehicles at rest. The accident

scene extended about 1,000 to 1,700 feet south of

CTH K.

The doubles truck tractor was found facing

southeast in the southbound left lane; its

semitrailer was facing southwest, also in the

southbound left lane, and the full trailer was

facing northwest in the median. Tire marks in the

northbound lanes started approximately 1,260

feet south of the CTH K overpass. The 127-footlong tire marks on the pavement began in the

right lane and continued across the left lane into

the median. They were clean scrub marks that

started out faint and became more distinct and

uniform. The 145-foot-long plow marks in the

median led to the point-of-rest for the doubles

truck.

The flatbed’s tractor and semitrailer were

facing south in the area between the northbound

lanes and the exit ramp to CTH K. The fluid trail

(battery acid) in the southbound lanes started

about 1,577 feet south of the CTH K overpass.

The 146-foot-long fluid trail began in the right

lane, crossed the left lane, and led to the median.

The average length of the tire marks that crossed

this area of the median was 96 feet; the tire

marks led to a scrape mark in the northbound

lanes. The scrape mark crossed the left lane and

went into the right lane toward the final rest

position of the flatbed truck.

The van was found facing north-northeast,

partially in the right lane and partially on the

right shoulder. Additional scrape marks, about

 

21The Manual on Uniform Traffic Control Devices is

approved by the Federal Highway Administration as the

standard for all streets and highways in accordance with

Title 23, United States Code, Sections 109 (b), 109 (d),

and 402 (a) and 23 CFR 1204.4.
22

10 inches long and curved, were found in the

right lane near the passenger van.

The refrigerator truck came to rest facing

north in the median. (See figure 8 for a diagram

showing the physical evidence.)

Traffic Volumes and Speeds -- WisDOT

has a vehicle monitoring station on US 41, in

Allenton, 4 miles north of the accident site. The

station monitors traffic volumes and speeds. The

average daily traffic (ADT) counts obtained from

this station for 1993 through 1996 are shown in

table 4.

The posted speed limit was 65 mph and the

highway design speed was 70 mph. On the

morning of the accident, between midnight and 6

a.m., the average speed for northbound vehicles

was 57 mph and the 85th percentile22 speed was

64 mph. The average speed for southbound

vehicles was 62 mph and the 85 th percentile

speed was 69 mph.

Accident Statistics -- According to

WisDOT accident records, the 6-mile span of

 

22The 85th percentile represents the speed at or below

which 85 percent of the vehicles had been moving during

that period of time.

US 41 centered on the accident site (3 miles of

the roadway in each direction from the site) had

21 reported accidents from 1994 through 1996.

Seven accidents involved collisions with deer; six

others occurred on ice or snow. Two accidents

involved tractor semitrailers that jackknifed.

A review of the individual reports found that

none of the reported accidents involved vehicles

crossing over the median. Like the accident forms

for most States, the Wisconsin accident form

does not have a specific code for crossover

accidents.

Because “head-on collision” was the closest

descriptive code available in existing accident

information to the circumstances of the Slinger

accident, the Safety Board examined head-on

collision data to determine the extent of crossover

accidents in Wisconsin. Head-on collisions

involving fatalities on divided highways with and

without median barriers in Wisconsin are shown

in table 5.

Table 4 -- Traffic volumes

Year Average Daily

Traffic

Northbound Southbound Percent

Trucks

1993 21,370 11,160 10,210 21

1994 21,940 11,450 10,490 NA

1995* 23,980 12,040 11,940 NA

1996 24,050 11,930 12,120 NA

*The ADT for 1995 is incomplete (missing 2 months of data) because of equipment problems.
23

Figure 8 -- Diagram highlighting the physical evidence

B lue Passenger Van

Final Rest Postion

Gouge

Mark

Entrance R am p

From C TH-K

Refrigerator Truck

Final Rest Position

Flatbed Truck

Battery Acid Trail

Curved

Scrape

Mark

Doubles Truck

Final Rest Position

Southbound

US Highway 41

A pproxim ate S cale

in Feet

Flatbed Truck

Final Rest Position

E xit R am p

to CTH -K

0 5' 10' 20' 40'

N

E

S

W

D oubles Truck

Tirem arks

N orthbound
24

Table 5 -- Head-on collisions in Wisconsin on divided highways

*In June 1996, the speed limit was raised from 55 to 65 mph on certain freeways and expressways in

Wisconsin, including the section of US 41 where the crash occurred. Between June 1996 and February

1997, a total of 21 highway fatalities occurred in Wisconsin.

To determine the extent of crossover

accidents nationwide, the Safety Board examined

the National Highway Transportation

Administration (NHTSA) 1995 Fatality Analysis

Reporting System (FARS).23 The FARS data

does not have a separate crossover accident code.

To capture cross-median accidents, the Safety

Board examined accidents in which the most

harmful event was coded as “a motor vehicle in

transport in other roadway”24 or head-on

collision. Of the 830 vehicles involved in these

accidents, 728 were on divided highways without

barriers and 91 were on divided highways with

traffic barriers. There were 560 fatalities in the

accidents that occurred on the divided highways

without traffic barriers and 60 fatalities in the

accidents on the divided highways with traffic

barriers.

Adverse Weather Countermeasures --

Snow and ice removal on the Wisconsin State

 

23FARS formerly referred to the Fatal Accident

Reporting System.

24This code applies to events in which the vehicle

leaves one roadway and enters a different roadway and has

a collision with a motor vehicle in transport in a different

roadway. For example, one vehicle travels across the

median of a divided highway, enters oncoming traffic, and

is struck. Another example would be when a vehicle

traveling on an overpass leaves that trafficway and strikes

or is struck by a vehicle traveling on a trafficway below.

highway system is performed by contract with

the county highway departments. Winter storm

maintenance on State highways in Washington

County is carried out by the Washington County

Highway Department. The 26 miles of US 41 are

divided into three parts, identified as sections 7,

8, and 9. The accident took place in section 8.

Each section is about 8 miles long, not including

ramps. (The section boundaries are shown in

figure 9.)

Each of the snow and ice removal equipment

drivers for the accident region had 8 to 10 years

of experience in their respective sections. All

three (one driver per section) drove 1997

International Harvester Corporation trucks

equipped with MA-5000 Ice Control System

Power Drive units and Gresen Model GRS-32

Spreader Control Systems. Each truck had a 10-

to 11-ton load capacity.

On the morning of the accident, as the crews

were plowing the blowing snow, the driver in

section 8 noticed black ice forming in the right

lane. He notified the other drivers, and they

began applying salt and a wetting agent (liquid

calcium chloride) to the roadway as well as to the

ramps.

With Median Barriers Without Median Barriers

Year Fatal Percent

of Total

Total Fatal Percent

of Total

Total

1994 1 0.6 166 4 1.2 339

1995 0 -- 86 7 2.9 244

Jan -Nov 1996* 1 1.2 81 4 2.0 196

TOTAL 2 0.6 333 15 1.9 779
25

Figure 9 -- Snow section boundaries
26

According to the drivers, it took an average

of 1 1/2 to 2 hours to cover each section,

including the ramps. The driver in section 8 said

that, by about 5:15 a.m., he had completed a loop

over the north- and southbound lanes in his

section and his truck was empty. While en route

to the maintenance shop to pick up another load

of salt and wetting agent, he noticed that the

southbound roadway was wet. He was reloading

chemicals when he was advised that an accident

had occurred at 5:52 a.m. in the northbound lanes

near CTH K.

The accident site received two applications of

salt and wetting agent. The driver in section 9

stated that he overlapped section 8 as he

completed his loop and made his U-turn south of

the interchange. All three crew drivers indicated

that it was not uncommon for them to overlap

sections as they completed their loops.

Wisconsin Department of Transportation

Maintenance Manual -- According to the WisDOT

Highway Maintenance Manual (HMM), plowing

or other mechanical means of snow removal are

preferable, for environmental and budgetary

reasons, to using chemicals, such as rock salt

(sodium chloride) and a wetting agent (calcium

chloride liquid), or abrasives (sand).

The Washington County crews applied salt

at a rate of 400 to 500 pounds per lane mile, with

8 to 9 gallons of liquid calcium chloride per ton,

after black ice conditions were reported. The

HMM specifies that spreaders should have the

capability of delivering chemicals to the center

two-thirds of the pavement at a maximum

application rate of about 300 pounds per lane

mile. The Washington County superintendent

told the Safety Board that, from his experience,

300 pounds per lane mile of material was

insufficient. He said he routinely instructed his

crews to begin applying the material at 400

pounds per lane mile or more as needed. He also

stated that salt alone is less effective when the

surface temperature is below 20°F and that at

such temperatures, liquid calcium chloride, which

acts as a dehydrator, is needed to begin the

brining action on the roadway to further enhance

the removal of snow and ice.

The WisDOT District 2 supervisor told the

Safety Board that,

There are numerous variables that could

affect the rate at which the chemicals and

surface moisture begins to refreeze, such

as a drop in the surface and ambient

temperatures, high winds, and little to no

traffic to continue the brine action.

Based on the conditions on the morning of

the accident, he thought it could have taken 2

hours or longer for the surface moisture to

refreeze after the last application of chemicals.

The HMM states that locally available

abrasive material, usually sand, should be used

when pavement temperatures are 0°F or less, or

when chemicals are ineffective because of high

winds or other storm conditions. According to the

Washington County superintendent, abrasives are

rarely used when it is windy because they are

blown off the roadway. Instead, road crews use a

premix consisting of 99.9 percent pure calcium

chloride in the form of pellets or flakes, applied

with sodium chloride at a rate of 10 percent.

The accident site was open, unlike the areas

north and south of CTH K, where living snow

fences (evergreen trees or shrubs or both) break

the wind. The HMM specifically addresses the

problem of blowing and drifting snow causing

slush and ice; it states that “Snow fences can be

effective in preventing snowdrifts, improving

visibility, and reducing slush and ice.” The

HMM further states that living snow fences are

desirable in areas where right-of-way widths are

adequate to provide snow storage.

Road Weather Information System -- The

nearest WisDOT road weather information

system (RWIS) monitoring station with pavement

sensors was located about 10 miles east of the

accident site, near the intersection of U.S.

Route 45 and State Highway 60. Station records

indicate that, at the time of the accident, the road

surface temperature on U.S. Route 45 was

approximately 16°F and the surface wind was

out of the west at about 11 mph. The air

temperature was approximately 15°F and the

subsurface temperature was about 30°F. The

report indicated that the road had precipitation on

its surface, in the form of snow and ice,

consistently from 8:05 p.m., February 11, until

6:03 a.m., February 12. (See appendix C,
27

Roadway Weather Information System, for

further information.)

The General Billy Mitchell Airport, located

about 3 nautical miles southeast of Milwaukee,

reported that light snow began falling at 8:08

p.m., February 11, and continued until 3:16

a.m., February 12. About the time the accident

occurred, the airport weather station reported

clear skies, 9 miles visibility, winds out of the

northwest at 12 mph (310° at 10 knots), and a

temperature of 19.4°F. No National Weather

Service advisories were in effect.

The HMM provided guidance for storm

management, stating that the county storm

supervisor should provide the media with storm

information as appropriate. In addition, WisDOT

has a “1-800” roadway weather line and a Web

site that provide current road conditions

statewide. On the morning of the accident, the

weather line was reporting that the roads were

snow-covered and icy.

Other States -- The Safety Board examined

the deicing practices in States other than

Wisconsin. New York uses an application of 225

pounds of salt per lane mile; Iowa and Minnesota

use 250 pounds per lane mile during and after

snow and ice storms. A 1974 National

Cooperative Highway Research Program

(NCHRP) survey of 13 States25 showed

application rates that varied from 100 to 600

pounds per lane mile.26

In New York, when temperatures fall below

15°F, the State (depending upon conditions)

begins using abrasives (sand, cinders, and ash).

The sand piles are mixed with 4 to 10 percent

salt to allow the abrasives to stick to the

pavement and not blow away. Abrasives are used

to provide traction, not to melt the ice. When

conditions change and it warms up, New York

reverts to using chemicals (salt and wetting

agent).

 

25California, Idaho, Illinois, Kansas, Minnesota,

Missouri, Nebraska, New Jersey, New York,

Pennsylvania, South Dakota, Vermont, and West Virginia.

26Synthesis of Highway Practices #24, Minimize

Deicing Chemicals, NCHRP, 1974.

Recent Research -- One of the technologies

examined under the Strategic Highway Research

Program (SHRP)27 was snow and ice removal.

Conventional winter maintenance operations

involve deicing techniques, that is, sending plows

and trucks loaded with salt and other materials to

clear the roadways after a storm has begun. The

principle of anti-icing is to inhibit the bond

between the pavement and packed snow and ice

by applying a chemical that lowers the freezing

point of water. The SHRP undertook a project28

to examine five of the available types of chemical

brines commonly used in anti-icing: sodium

chloride, calcium chloride, magnesium chloride,

calcium magnesium acetate, and potassium

acetate. Chemical applications were made before

a storm, early in the course of a storm, or during

a storm, as plows created bare or nearly bare

pavement. The chemical could be applied to the

roadway to prevent frost or black ice if road

surface temperatures were expected to drop

below freezing. Sections of roadway could be

selected for different anti-icing treatments based

on such variables as traffic flow or pavement

type. Through this project, the SHRP found that

an anti-icing strategy coupled with an RWIS

could reduce winter maintenance costs, improve

travel conditions, and help protect the

environment. (Wisconsin, one of the 15 States in

this SHRP project, tested sodium chloride brine

at temperatures above 25°F.)

Subsequently, the Federal Highway

Administration (FHWA) and the States

conducted a field test to evaluate the anti-icing

technologies tested and reviewed in the SHRP

project. The field test included a two-winter

experimental anti-icing evaluation and analysis of

the experimental data. The recently issued

report29 of this evaluation concluded that well27Congress established the SHRP in 1987 as a 5-year,

$150 million project to develop and evaluate innovative

technologies for roadway construction, maintenance, and

operations. The SHRP was administered by the

Transportation Research Board and the Federal Highway

Administration.

28Blackburn, R. R.; McGrane, E. J.; Chappelow, C.

C.; Harwood, D. W.; and Fleege, E. J., Development of

Anti-Icing Technology, Report No. SHRP-H-385, National

Research Council, Washington, D.C., 1994.

29Ketcham, S. A.; Minsk, L. D.; and Danyluk, L. S.

Test and Evaluation Project No. 28: Anti-icing

Technology, Field Evaluation Report, FHWA-RD-97-132,

March 1998.
28

timed initial chemical applications can prevent or

mitigate reductions in friction, as well as support

the anti-icing objective of preventing a strong

bond from developing (between the ice and the

pavement).

Research in Wisconsin -- According to

WisDOT,30 Wisconsin is reviewing three new

anti-icing technologies during winter 1997-98.

The first, being tried in Columbia and Brown

Counties, involves spreading fine- and mediumgrade salt in addition to the coarser road salt. The

finer-graded salts are used because they react

more quickly with moisture during conditions

under which ice is expected to form. The effects

of the finer grades typically do not last as long as

the effects of the coarser-grade salts. The second

technology, being tested in Walworth County, is

an anti-icing device that is mounted directly on

one of two parallel bridges on Interstate 43. The

device, which is activated when ice conditions are

forecast, will automatically spray the bridge with

deicing chemicals to prevent the formation of ice.

The third program, being conducted in eight

counties (Adams, Brown, Douglas, Eau Claire,

Florence, Oneida, St. Croix, and Trempealeau),

involves the use of liquid magnesium chloride to

treat roads just before a storm.

Nationwide Standards -- Although national

standards for snow and ice removal do not

currently exist, the issue continues to be

explored. In 1996, the FHWA published a

Manual of Practice for an Effective Anti-icing

Program: A Guide for Highway Winter

Maintenance Personnel. In addition, a current

NCHRP Project 20-7 Task 83 is developing a

“Guide for Snow and Ice Control,” which is

expected to be completed in 1998. NCHRP

Project 6-13, which began in March 1998, is to

develop “Guidelines for Snow and Ice Control

Materials and Methods.”

 

30WisDOT: News Releases, “Doing Battle with

Winter: Counties, State, and FHWA Test Ways to Make

Winter Roads Safer,” December 8, 1997. “Doing Battle

With Winter: Eight Counties Test Liquid Anti-icing

Approach to Keep Roads Ice Free,” November 20, 1997.

The AASHTO Winter Maintenance Policy

Committee’s Snow and Ice Cooperative Pooled

Fund Program sponsored, in cooperation with 34

States, the American Public Works Association,

and the National Association of County

Engineers, a conference in Minneapolis in April

1997. One of the outcomes of this conference

was the recognition of the need for training in

new anti-icing and RWIS technologies.

Large Truck Crashes -- According to the

NHTSA statistics from the FARS data, in 1994,

some 5,112 people died in large-truck crashes.

(NHTSA defines a large truck as one weighing

more than 10,000 pounds.) Twenty-four percent

of large-truck crashes occur on freeways.

A University of Michigan Transportation

Research Institute Truck and Bus Accident

Factbook analysis of truck accidents indicated

that, during 1994, “most truck accident

involvement occurred on dry roads.”31 Table 6

summarizes the findings of this analysis.

A recent study32 conducted in Indiana by the

Insurance Institute for Highway Safety, in

conjunction with the Indiana University

Transportation Center, found that doubles trucks

were significantly over-involved in crashes on

roads with snow, ice, or slush. The study

examined 2,033 incidents involving a tractor

pulling one or two trailers that occurred on the

interstate from October 31, 1989, to March 31,

1991. The study excluded crashes involving

bobtails (truck tractors without trailers), singleunit trucks, and triples, as well as crashes

occurring at toll plazas or entrance or exit ramps.

(A high proportion of doubles rollover accidents

occur on ramps and curves.)

 

31Truck and Bus Accident Factbook, 1994, prepared

by the Center for National Truck Statistics, University of

Michigan Transportation Research Institute, for the Office

of Motor Carriers, FHWA, October 1996, UMTRI-96-40,

p. 21.

32Braver, Elisa, R.; Zador, Paul, L.; Thum, Denise;

Mitter, Eric, L.; Baum, Herbert, M.; and Vilardo, Frank,

J., “Tractor-Trailer Crashes in Indiana: A Case-Control

Study of the Role of Truck Configuration,” Accident

Analysis and Prevention, Vol. 29, No. 1, 1997, pp. 79-96.
29

Table 6 -- 1994 Truck accidents by road conditions*

*These numbers come directly from the 1994 Truck and Bus Accident Factbook.

The study found that, compared to singletrailer vehicles, double-trailer vehicles had a

decreased risk of crash involvement on dry and

wet pavements (excluding snow, ice, and slush)

and in multiple vehicle crashes but an increased

risk of involvement in crashes occurring on road

surfaces with ice, snow, or slush. In Indiana, 14

percent of passenger car crashes on the interstate

occurred on snow, ice, or slush during 1990. This

finding compared to 21 percent of interstate

crashes for single-trailer vehicles and 45 percent

of interstate crashes for double-trailer vehicles,

for the period from October 31, 1989, to March

31, 1991.

The Truck and Bus Factbook indicated that

“jackknife”33 occurred in 5 percent of all

combination vehicle (tractor and one or more

trailers) accidents. The Factbook found that

combination vehicles weighing 20,000 to 30,000

pounds jackknifed in 15 percent of these

accidents, compared to 3.2 percent for

combination vehicles weighing 70,000 to 80,000

pounds. These data show that lighter vehicles

tended to jackknife about five times more often

than heavier vehicles.

 

33The term jackknife describes what happens when a

tractor’s drive axle(s) loses traction, causing the tractor to

rotate and hit the trailers. When the rotation exceeds 15°,

the result is usually loss of control.

In four separate Safety Board safety studies34

involving 502 truck accidents that occurred

between 1985 and 1993, a total of 83 accidents

involved tractors pulling double-trailers. Of these

83 accidents, 19 involved empty or lightly loaded

doubles (gross vehicle weights of 45,000 pounds

or less) and 12 of the 19 occurred on slippery

pavement, where the coefficient of friction

between the tire and the roadway was considered

a factor in accident occurrence.35 The Safety

Board knows of no public or privately funded

studies that have specifically quantified and

compared the number of empty doubles accidents

on slippery pavements to the number of loaded

doubles accidents on slippery pavements.

Medians -- In the course of the investigation,

the Safety Board looked at factors affecting

highway medians.

 

34For more information, see (1) NTSB/SS-88/05,

Case Summaries of 189 Heavy Truck Accident

Investigations, (2) NTSB/SS-90/01, Fatigue, Alcohol,

Other Drugs, and Medical Factors in Fatal-to-the-Driver

Heavy Truck Crashes, (3) NTSB/SS-92/01, Heavy Vehicle

Airbrake Performance, and (4) NTSB/SS-95/01, Factors

That Affect Fatigue in Heavy Truck Accidents.

35Safety studies do not claim to be statistically

representative in either the number or type of accidents

investigated.

ROAD

CONDITION

FATAL INJURY TOW AWAY ALL

No. % No. % No. % No. %

Dry 3,820 79.7 41,000 73.4 64,000 71.0 109,000 72.1

Wet 718 15.0 11,000 20.3 16,000 18.4 29,000 19.0

Snow/slush 109 2.3 1,000 1.2 3,000 3.7 4,000 2.7

Ice 116 2.4 3,000 4.8 6,000 6.9 9,000 6.0

TOTAL 4,795 100.0 56,000 100.0 90,000 100.0 151,000 100.0
30

Widths -- The current design guidelines of

the FHWA, AASHTO, and WisDOT

recommend 60-foot medians on freeways. In

January 1990, when WisDOT increased its

Facilities Development Manual design

guidelines for medians from 50- to 60-foot for

freeways, most of the right-of-ways for the US

41 upgrade had been purchased. According to

WisDOT officials, this change in median width

standards came too late in the development

process for a significant change to be

incorporated into the US 41 upgrade.

Barriers -- In the area of the accident, US 41

does not have median barriers, and, according to

the current median barrier guidelines, no

barriers are needed. The AASHTO Roadside

Design Guide “suggests a warrant for median

barriers on high-speed, controlled-access

roadways which have relatively flat, traversable

medians.”36 The AASHTO warrant provides the

criteria for such median barriers. (See

appendix D for more information regarding

median barrier warrants.)

The AASHTO warrant criteria are based on

a 1968 California accident study37 and 1974

research38 performed by Texas A&M

University; they consider ADT, median width,

and cross-median accident history. The warrant

criteria do not take into account the percentage

of heavy trucks in the ADT.

In June 1997, the California Department of

Transportation (Caltrans) changed its policy

regarding its freeway median barrier

volume/width study warrant.39 Caltrans

recognized that a 25-percent increase in freeway

traffic; changes in vehicle designs; adjustments

in driver skills, abilities, and attitudes; and

increases in speed limits had altered the

 

36Roadside Design Guide, AASHTO, Washington,

D.C., 1990, chapter 6, p. 1.

37Graf, V. D. and Wingerd, N. C., “Median Barrier

Warrants,” Traffic Department of the State of California,

1968.

38Ross, H. E. Jr., “Impact Performance and Selection

Criterion for the Texas Median Barriers,” Research Report

140-8, Texas Transportation Institute, Texas A&M

University, 1974.

39Caltrans internal memorandum to all district

directors from Traffic Operations, dated June 27, 1997.

historical trend surrounding the probability of

cross-median accidents. Caltrans extended its

policy to a 75-foot median-barrier-freewayvolume/width-study warrant. Caltrans expects to

cut the annual number of fatal cross-median

accidents on the State’s freeway system in half

by this action. During the past 5 years,

California has averaged 35 fatal cross-median

accidents a year.

In 1993, North Carolina conducted a study

that found that 105 deaths had occurred in 751

head-on collisions that took place from April

1988 through October 1991. These collisions

represented 3 percent of the State’s highway

crashes and nearly one-third of the fatalities. As

a result of the study, North Carolina began a

$24 million dollar project to install median

barriers in 24 locations on the interstate system.

Cross-median Accident Coding -- Since the

Slinger accident occurred, the Safety Board has

investigated several other cross-median

accidents and has found that cross-median

accident histories are not readily available. Most

States do not have a cross-median accident code

on their accident report forms.

About 9:55 p.m. on April 25, 1997, a

southbound doubles truck operated by UPS lost

control and crossed over the 64-foot grass

median of Interstate 95 in Jacksonville, Florida.

The doubles truck collided with a passenger car

and a tractor semitrailer in the northbound lanes.

All vehicles were damaged extensively and four

fatalities resulted.40

While trying to determine the accident

history for this location, the Safety Board was

told by Florida Department of Transportation

officials that they had experienced difficulty in

identifying median crossover accidents. For

example, at one location, a few miles in length,

they were aware of several median crossover

accidents, yet their efforts to identify these

accidents by searching the records were

unsuccessful. On the official report of the

Jacksonville accident, both the contributing

circumstance and the harmful event were coded

as “other.”

 

40For more information, see docket for CHR-97-FH005.
31

A review of the NHTSA publication, State

Accident Report Forms Catalog, 1995 Update,

revealed that six States, (Hawaii, Indiana,

Louisiana, Massachusetts, Michigan, and

Missouri) have a data element on their reporting

forms for “median crossover” accidents.

NHTSA, the FHWA, and the National

Association of Governors’ Highway Safety

Representatives (NAGHSR) are developing a

Guideline for Minimum Uniform Crash

Criteria. The Safety Board reviewed the October

1997 draft of this document and found no

mention of crossed medians as a data element.

Toxicological Tests

Results -- In accordance with the DOT

regulations (49 CFR 382.303), which require

specimens to be tested for alcohol, cocaine,

marijuana, amphetamines, PCP, and opiates,

initial laboratory toxicology tests were performed

on specimens from the three truckdrivers

involved in the Slinger accident. Specimens for

testing were obtained from the van driver during

an autopsy conducted by the Milwaukee County

Office of the Medical Examiner. The results are

in table 7.

Table 7 -- Results of initial laboratory toxicology tests

*Except for the specimens taken during the autopsy of the van driver on February 13, 1997, all specimens

were taken on the day of the accident, February 12, 1997.

DRIVER SPECIMENS TIME

SPECIMENS

TAKEN*

RESULTS

ALCOHOL DRUGS

Doubles truck Breath 11:06 a.m. negative negative

Urine 11:00 a.m. negative negative

Flatbed truck Blood 4:30 p.m. negative negative

Breath 5:08 p.m. negative negative

Urine 4:30 p.m. negative negative

Passenger van Blood February 13 negative negative

Urine February 13 negative negative

Vitreous humor February 13 negative negative

Refrigerator truck Breath 11:34 a.m. negative negative

Urine 11:45 a.m. negative positive
32

The Safety Board submitted specimens from

all drivers except the CF doubles truckdriver41

for additional analysis to the Center for Human

Toxicology in Salt Lake City, Utah. These tests

were negative for alcohol and drugs, except for

the urine specimen test for the refrigerator

truckdriver, which showed the following:

• 41 ng/ml

42 COOH-THC, (an inactive

metabolite of marijuana);

• 346 ng/ml diphenhydramine (a

sedating over-the-counter antihistamine); and,

• 11.1 ug/ml

43 acetaminophen (an

over-the-counter medication for mild

pain and fever).

After the accident, the refrigerator

truckdriver stated that he had ingested marijuana

several days before the accident.

Timeliness -- Federal regulations require

that a breath test for alcohol be obtained within 2

hours of an accident. If that is not accomplished,

the carrier must have a record on file as to why

the test was not performed. The regulations

further state that if alcohol tests are not

accomplished within 8 hours, the carrier shall

cease attempts to administer the tests and prepare

and maintain a record as to why the specimens

were not obtained. Urine specimens for drug

testing must be obtained within 32 hours of

an accident.

Toxicological specimens were obtained from

the doubles and refrigerator truckdrivers within 6

hours of the accident and from the van driver’s

autopsy the next day. Specimens were not

obtained from the flatbed truckdriver until

 

41After the lab that CF hired to analyze the urine

specimen provided by the doubles truckdriver found the

specimen negative for the presence of drugs, it destroyed

the specimen.

42Denotes nanograms (billionths of a gram) of drug or

metabolite present per milliliter of specimen.

43Denote micrograms (millionths of a gram) of drug

or metabolite present per milliliter of specimen.

late afternoon, 10 1/2 hours after the accident,

which did not meet Federal drug testing

timeliness requirements for the breath test for

alcohol.

The flatbed truck carrier’s Human Relations

representative informed Safety Board

investigators that she was notified midmorning on

February 12, 1997, that the driver had been

involved in an accident, and that he was required

to undergo postaccident alcohol and drug testing.

She indicated that the driver thought the

specimens had been taken at the hospital, and it

was late afternoon before the carrier could

arrange to have them taken at a clinic.

Survival Aspects

Restraint Use -- The refrigerator

truckdriver, who was not injured, was wearing

the available lap/shoulder belt. The doubles and

flatbed truckdrivers, who received minor injuries,

were both wearing the available lap/shoulder

belts.

According to rescue workers, the driver and

the right front passenger of the van, both of

whom sustained fatal injuries, were wearing the

available lap/shoulder belts. The driver’s

supplemental airbag had deployed and the pretensioner device44 had activated. Although

restraint systems were available, nothing

indicated that the remaining van passengers had

been restrained. The surviving passenger initially

stated that none of the passengers beyond the

front seat of the van had been using seat belts. He

also indicated that he was aware that Wisconsin

had a mandatory seat belt law. (Refer back to

figure 6 for seating and restraint availability and

see figure 10 for injury distribution and restraint

use.) He told investigators that the cargo in the

van had been stored several feet in front of him.

 

44A pre-tensioner device is designed to take the slack

out of a seat belt during the first milliseconds of a

collision.
33

Figure 10 -- Injury distribution and restraint use

Survivor: 57-year-old

male: Fractures of the left

and right acetabulum and

the right tibia and fibula.

Fractures of the left

forearm. No head or chest

injuries.

Fatality: 50-year-old male:

Multiple rib fractures with

inferior displacement.

Multiple internal injures.

Skull fracture. Bilateral

fractures of the tibia and

fibula.

 Fatality: Driver 39-

year-old male: Skull

fractures, multiple rib

fractures, internal

injuries, and multiple

leg fractures

Fatality: 57-year-old male:

Skull fractures, multiple

fractures of the ribs, internal

injuries. No fractures of the

lower legs noted.

Fatality: 60-year-old male:

Multiple chest injuries

including fractures of the

ribs. Internal injuries.

Skull fracture with

fragmentation.

Fatality: 62-year-old male:

Partial (50%) amputation

of the left shoulder. Closed

head trauma with severe

brain injury. Abrasions

over tibia regions of both

legs. Rib fracture.

Fatality: 43-year-old male:

Brain injuries, multiple

fractures of the face,

bilateral fractures of the

tibia and fibula, fracture of

the right wrist.

Fatality: 60-year-old male

seated in cargo area with back

against left sidewall. Skull

fracture and multiple chest

injuries. No fractures of the

lower extremities noted.

 Fatality: 57-year-old

male: Fractures of all

major skull bones,

fractures of all ribs,

internal injuries, and

multiple fractures of

the extremities

Lap/Shoulder belt worn

Airbag deployed

Pre-tensioner device activated

Lap/Shoulder belt worn

Seated on floor

No evidence of restraint use No evidence of restraint use No evidence of restraint use

No evidence of restraint use No evidence of restraint use No evidence of restraint use

Row 1

(Bucket Seats)

Row 4

(Bench Seat)

Row 5

(Bench Seat)
34

Wisconsin Seat Belt Use Law -- The

Wisconsin seat belt mandatory use law (MUL)45

is enforceable for seating positions with

lap/shoulder belts only. The Wisconsin MUL is,

like those in the majority of States, a secondary

enforcement law. Secondary enforcement means

that a police officer cannot issue an individual a

ticket for not wearing a seat belt unless the

officer has had to stop the individual for some

other infraction. Wisconsin allows evidence of

failure to wear a seat belt in a court of law,

permitting mitigation of 15 percent of the

damages that may be recovered by a plaintiff

who failed to wear a seat belt.

According to the Wisconsin Governor’s

office, the Wisconsin seat belt use rate is 61.7

percent,46 compared to the national average of 68

percent. Evidence indicates that States and

countries with stricter seat belt use laws have

higher seat belt use rates.47

Emergency Operations Plan --

Washington County has an Emergency

Operations Plan. The EMS portion of the plan

can be called upon in several different emergency

situations, including weather, fires with large

numbers of victims, and public transportation

accidents (bus, train, and plane). Although the

plan does not have a specific provision for multivictim accidents involving private vehicles, it

makes provision for natural or man-made

disasters that exceed the routine capabilities of

the local EMS response system. In addition, the

SFD and other local response agencies have a

mutual aid agreement.

Tests and Research

The Safety Board tested several components

of the vehicles involved in the collisions.

Doubles Truck ECM -- The Cummins ECM

on the doubles truck was read at the Cummins

 

45Found in Wisconsin Statutes Vehicle Code, chapter

347, section 347.48 (as of 1991).

46January 5, 1998, telephone conversation between a

Safety Board staff member and a member of the

Governor’s staff.

47See Proceedings of the National Transportation

Safety Board Public Forum on Air Bags and Child

Passenger Safety, March 17-20, 1997, Washington, D.C.,

Report of Proceedings (NTSB/RP-97/01).

Great Lakes facility in Milwaukee, Wisconsin,

on February 15, 1997. The ECM did not have

optional on-board recording features; it was only

configured to operate as an ECM. Consequently,

the readout did not provide any vehicle speed or

engine rpm data for the doubles truck.

Passenger Van ECM -- The airbag system

on the passenger van was equipped with an ECM

manufactured by Bosch. According to Chrysler,

the module cannot archive any vehicle crash

deceleration “G-pulse” information.

One method of determining the crash pulse to

which a vehicle is exposed during a collision is

the use of a crash-pulse-recording device.

Currently, 60,000 vehicles in Sweden equipped

with crash recorders are being tracked to gather

data aimed at improving occupant protection in

collisions.48 Similar research is being conducted

in the United States involving race cars.49 Some

vehicles currently marketed in Europe and the

United States have crash pulse recorders. As

noted above, the model of van involved in this

accident does not require the storage of a crash

pulse, and none was recorded.

The Safety Board attempted to calculate the

crash pulse and delta-v (change of velocity) of

the passenger van’s collision with the flatbed

truck using force deflection curves determined

from crash test data. This calculation could not

be successfully completed because different

impact configurations for the same vehicle

produce different force deflection curves.50

Because the passenger van sustained underride

engagement at two different levels, in addition

 

48From the proceedings of the 1996 International

Research Council on the Biomechanics of Impact,

September 11-13, 1996, p. 212.

49Melvin, John, W; Baron, Kenneth, J.; and Little,

William, C: Investigation of Indy Car Crashes Using

Impact Recorders, 1996, Society of Automotive Engineers.

50An underride crash test and a flat frontal barrier

crash test performed at the same impact speed can produce

different force deflection curves for the same vehicle.

These differences occur because underride damage is

sustained in the “softer” sheet metal above the frame,

which results in lower forces being generated during the

collision for a given crush depth. The flat frontal barrier

test engages “harder” structures, such as the frame and the

engine, in a longitudinal direction, and so generates

greater forces than the underride at the same impact speed.
35

to partial engagement of the front bumper, a

force deflection curve could not be accurately

calculated using the available crash test data for

frontal flat barrier impacts. A search of underride

crash test data found no relevant testing for

similar vans.

Passenger Van Restraint Systems -- The

Safety Board’s Materials Laboratory examined

the seat belt, belt retractor, retractor mount bolt,

and D-ring assembly from the left outboard of

the row 4 seat belt assembly. Plastic transfers

from the D-ring were found on the belt.

Doubles Truck Road Test -- On July 23,

1997, Safety Board investigators, in conjunction

with CF representatives, performed a road test in

a doubles truck that was “sister” to the accident

vehicle to determine the maximum speed at which

an operator could downshift from 7th to 6th gear.

The test showed that the maximum speed was 55

mph. This downshift was accomplished with the

benefit of a “governor override” and, according

to CF personnel, the normal downshift from 7th to

6th gear would be made at speeds of less than

47 mph, the top speed in 6th gear.

Other Information

Vehicle Underride -- NHTSA reports that

about 500 to 600 deaths occur each year when

smaller vehicles underride large trucks or trailers.

The current Federal law (dating back to 1953)51

requires “rear guard” (rear end) protection if the

trailer has a ground clearance of more than 30

inches. No specific requirements regulate the

strength of the rear guards. In the intervening

years, lower-hood-profile cars have been

manufactured and this configuration is currently

the “norm” for most small cars.

The new Rear Impact Guards; Rear Impact

Protection52 law became effective on

January 26, 1998. The main change in the

standard is that rear guard protection is required

if the trailer has a ground clearance of more than

22 inches. Further, specific strength

 

5149 CFR, Part 393.86.

5249 CFR, Parts 571.223 and 571.224.

requirements, which did not appear in the 1953

law, are present in the new law.

Neither the previous Federal law nor the

current law addresses the issue of side underride.

The Safety Board knows of no Federal

regulations currently being drafted to address

side underride. The situation is different in

Europe as “Side-underride guards developed to

protect motorcyclists, bicyclists, and pedestrians

from entrapment are now utilized in Europe.”53

Vehicle Conspicuity -- Neither the doubles

truck nor the flatbed truck had any special

reflectorized markings on the trailers other than

the required lights and lens reflectors. The

Federal Conspicuity Systems law54 mandates that

all trailers manufactured after December 1, 1993,

with a GVWR in excess of 10,000 pounds and a

width of at least 80 inches have “retro-reflective

sheeting” tape along the sides and rear of the

trailer. The law also requires each truck tractor

manufactured on or after July 1, 1997, to be

equipped with either reflective sheeting, reflex

reflectors, or a combination of sheeting and

reflectors. The commercial vehicles in this

accident were all manufactured before the

effective dates in the law.

Phase 4 Computer Simulation -- The

Safety Board sought to determine, by conducting

simulations, whether the use of a traction control

device or system could have ameliorated the

doubles truck’s jackknife. One model for such a

simulation is the Phase 4 vehicle dynamics

model. The Safety Board contracted with

University of Michigan Transportation Research

Institute staff to run the Phase 4 model with input

parameters from this accident.55

The primary focus of the simulation was on

the jackknife loss-of-control event and how a

wheel slip control mechanism (traction control)

 

53Badger, Joseph E., Trailer Underride (a publication

of the Institute of Police Technology and Management,

University of North Florida), revised 1995, p. 30.

5449 CFR, Part 571.108, S5-7.

55MacAdam, Charles C., Summary Report of

Findings from a Computer Simulation Analysis of the

Slinger, Wisconsin, Accident Involving an Unladen

Doubles Combination, December 1997.
36

on the tractor rear axle might have influenced the

outcome of this accident. Traction control

devices are based on antilock brakes in that they

assess the rate of wheel spin-up and apply brake

force to control those situations in which the

wheel is loosing traction. Antilock brakes can

help avoid locked wheels in braking by using

sensors that monitor the rate of wheel rotation. If

the sensors sense that a wheel is “spinning down”

at a rate that will lock, the system momentarily

releases the brake force to that wheel. Antilock

brakes are required to be installed on all truck

tractors manufactured after 1997.

Traction control systems can assist passenger

vehicles and trucks in maintaining headway when

ascending snow- or ice-covered grades. Also,

these systems can prevent loss of traction at truck

tractor drive wheels while under power and

reduce the incidence of power-induced jackknife.

Brake manufacturers indicate that the cost of

adding traction control devices to a tractor would

be about 10 to 28 percent of the cost of antilock

brakes, which makes up 1 to 2 percent of the cost

of a tractor. The percentage of the cost for

trailers would be higher.

In conducting the Phase 4 model simulations

in this case, simulated operating conditions

included an icy road and an 11-mph crosswind.

Simulated driver behavior included an initial

throttle application to maintain speed and

subsequent throttle release at the beginning of the

tractor directional instability. The findings of the

simulations indicated that the wheel spin-up and

the accompanying loss of lateral tire forces at the

rear tractor axle resulted in an initial jackknife by

the tractor that could not be arrested by the

driver, even with rapid countersteering. The

simulation identified the main contributors to the

loss of control as vehicle speed, vehicle

loading/configuration, tire/road friction level, and

crosswind magnitude.

Examination of the basic slip control

mechanisms on the tractor’s rear axle suggested

some potential for assisting drivers in

maintaining better directional control of the

tractor under such severe operating conditions.

Although tractor instability was not prevented by

the use of tractor slip control mechanisms in

several simulations, the rapidity of control loss

was generally diminished and often resulted in

driver responses that prevented an immediate

jackknife and ensuing median crossover. The

simulations indicated that an apparent benefit of

traction control might be the redirection of the

tractor by the driver following the onset of the

initial instability and improved, albeit oscillatory,

path control. (See appendix E for the Phase 4

simulation summary.)

Heavy Truck Simulators -- Simulations of

conditions have been shown to be helpful in

training operators in various transport modes.

The insurance and trucking industries have used

trucks with outriggers on skid pads for training

safety directors and conducting research.

Simulators have been used extensively in the

aviation industry to train operators on how to

deal with those conditions that would be either

too dangerous or impractical to enact for practice

purposes. Simulators are also used extensively in

the railroad industry as a primary training tool to

teach new engineers about train handling.

The Safety Board has learned that LockheedMartin Information Systems (LMIS) in Orlando,

Florida, is developing a heavy truck simulator.

The LMIS manager of Trainer Systems

Programs described the mechanism as a fullmotion simulator based on a standard tractortrailer configuration. The simulator allows

individuals to operate in simulated conditions of

various degrees of light, snow, wind, and fog.

Additionally, the simulator can alter some vehicle

dynamics, such as changing gross vehicle

weights. LMIS plans to construct another

simulator that will be configured for double

trailer operation.
37

This analysis will begin with a discussion of

the factors and conditions that the Safety Board

was able to exclude as neither causing nor

contributing to the accident. It will then provide a

brief overview of the accident events, a detailed

discussion of the issues and countermeasures,

and a discussion of the emergency response.

In this accident investigation, the Safety

Board identified the following safety issues:

• Judgment and experience of the

doubles truckdriver;

• Stability of doubles trucks;

• Effectiveness of snow and ice

removal;

• Adequacy of the AASHTO divided

freeway median barrier warrants;

• Adequacy of the States’ accident

report forms to capture cross-median

accident data; and,

• Availability and use of restraints.

General

None of the drivers’ specimens tested

positive for alcohol. A specimen from only one

driver, the refrigerator truckdriver, showed any

evidence of drug consumption. The Safety

Board examined the significance of the presence

of COOH-THC, a non-psychoactive metabolite

of marijuana, in the refrigerator truckdriver’s

urine specimen, and his statement that he had

ingested marijuana several days before the

accident. The presence of this metabolite is not

indicative of the level of tetrahydrocannabinol,

the psychoactive component of marijuana. Also,

the presence of an antihistamine and mild pain

and fever medication did not affect the driver’s

behavior in response to the accident

circumstances. All evidence indicates that the

refrigerator truckdriver swerved to the left to

avoid the collision with the flatbed truck. The

Safety Board considers that any unimpaired

driver faced with the rapidly developing accident

situation would respond similarly.

The Safety Board also examined driver

fatigue as it related to this accident and found

that none of the drivers involved in the accident

suffered from nor were impaired by fatigue

before the accident. The Safety Board did not

find any mechanical defects that caused or

contributed to the severity of the accident in any

of the involved vehicles. The Safety Board

therefore concludes that no alcohol use, drug use,

fatigue, or vehicle mechanical defects contributed

to this accident.

The Accident

The following material explains how the

combination of the wind, roadway conditions,

and speed of the doubles truck resulted in the

initial loss of control and the subsequent three

collisions of this accident sequence.

Wind -- The nearby WisDOT RWIS station

recorded surface wind out of the west at about 11

mph at the time of the accident. The Milwaukee

airport reported winds out of the northwest at 12

mph. The doubles truckdriver, the refrigerator

truckdriver, and the witness who followed the

passenger van all stated that they saw swirling

snow on the roads and commented on the slight

wind from the west. Therefore, the Safety Board

concludes that at the time and in the vicinity of

the accident, the wind was blowing at about 11 to

12 mph from the west.

Roadway Surface Conditions -- The

WisDOT RWIS station recorded that, at the

time of the accident, the road surface

temperature was about 16°F. The Washington

County road maintenance crews had noticed, and

were treating the roadway for, black ice. The

truckdrivers stated that the roads were wet in

Milwaukee, that the conditions became worse

(with the appearance of icy patches) as they

traveled north, and that the accident area was

icy. The emergency responders and other

witnesses also commented on the icy pavement at

the accident site. The Safety Board concludes

ANALYSIS
38

that at the time and in the vicinity of the accident,

the road had patches of ice.

Speed of the Doubles Truck -- The

doubles truck did not have a speed recorder and

the driver gave inconsistent statements to the

Safety Board and the police about the gear and

speed of his vehicle. He initially told the police he

was traveling in 4th gear; he later told the Safety

Board he was traveling in 6th gear at 35 to 40

mph. The Safety Board examined the physical

evidence, the witness statements, and the

limitations of the truck to determine the speed at

and gear in which the doubles truck was traveling

before the accident.

Although the doubles driver stated that he did

not apply the brakes before the loss of control,

the physical evidence indicates that the brakes

were applied during the accident sequence. The

tire marks on the pavement and through the snow

on the median were made by locked wheels. The

tire marks on the roadway were clean scrub

marks that started out faint and became more

distinct and uniform, indicative of a locked wheel

sliding across a wet pavement. A rolling wheel

would have left a “footprint” and a spinning

wheel would have left a mark that started out

darker and became light. In addition, the tire

marks across the snow-covered surface and in the

median were plow marks indicative of a wheel

sliding across the snow. A rolling wheel would

have left an imprint, not have plowed the snow

on the edge of the roadway or in the median. It

therefore appeared that the doubles driver

probably applied the brakes after the initial loss

of control.

The estimated speed of the doubles truck at

the time it lost control was calculated to have

been between 43 and 58 mph. This estimate is

based on the tire marks, the slope of the roadway

(0.006), and a range of coefficients of friction for

locked wheels on ice (a low of 0.07 and a high of

0.20) and snow (a low of 0.35 and a high of

0.55).56 The actual speed may have been higher

because the roadway may not have been entirely

covered with ice; it might have been wet or snowcovered with icy patches. Wet and snow-covered

 

56Traffic Accident Reconstruction, Volume 2, Traffic

Accident Investigation Manual, Northwest University

Traffic Institute, Lynn B. Fricke, Exhibit 15, “Coefficients

of Friction of Various Roadway Surfaces,” pp. 62-64.

pavements have higher coefficients of friction

than icy pavement and would result in higher

calculated speeds.

About 1.3 miles south of the accident site, a

witness estimated that the doubles truck was

traveling at about 60 mph. The witness stated

that he was traveling at 50 to 55 mph when the

doubles truck overtook him and started to pass.

The witness slowed to 45 mph to allow the

maneuver to take place quickly. This witness also

stated that he had been following the passenger

van for a while and that it was traveling at the

same approximate speed of 50 to 55 mph.

Therefore, according to the witness, at a point

about 1.3 miles south of the accident site, the

doubles truck, the passenger van, and the witness

were in the same approximate location at the

same time.

After the witness slowed to 45 mph during

the passing maneuver, the doubles truck and the

passenger van disappeared from his view. Unless

the passenger van slowed suddenly, the doubles

truck would have to have passed the van at about

55 to 60 mph in order to get several seconds in

front of it. It can be determined that the doubles

truck was several seconds in front of the van

during this period because the median crossover

by the doubles truck, its impact with the flatbed

truck, and the flatbed’s subsequent median

crossover all took place before the passenger van

reached the accident site.

Based on the minimum coefficient of friction

for the doubles truck and the minimum

deceleration factor for the flatbed truck, the

Safety Board calculated that the minimum time

necessary for the sequence of events to take place

from when the doubles truck lost control

until the van hit the flatbed truck was

16.1 seconds. For the doubles truck to have been

16.1 seconds ahead of the passenger van

traveling at 50 mph over the same distance of 1.3

miles, the doubles truck would have to have been

traveling at 60 mph.

The doubles truck was governed to a

maximum speed of 62 mph in 7th gear and

47 mph in 6th gear. Although the doubles truck

was ultimately found in 6th gear, the Safety

Board considers that, during the accident

sequence, the floorboard in the doubles cab

moved forward, causing the gear shift lever to
39

move forward from the 7th gear position to the 6th

gear position. (See figure 11 for the gear

diagram.) In addition, in order to achieve the

speed of 60 mph necessary to pass the passenger

van as occurred in this circumstance, the truck

would have to have been in 7th gear. Based on the

foregoing information, the Safety Board

concludes that, although the doubles truck was

found in 6th gear after the accident took place, it

had been traveling at the upper limits of the

calculated speed estimate of 43 to 58 mph, and

therefore it had been in 7th gear.

Doubles Truckdriver’s Initial Loss of

Control -- The doubles driver stated that he

“suddenly felt the trailers [tires] slip on the icy

roadway,” that the trailers “pushed forward and

towards the right,” and that he “immediately let

off the accelerator.” He further indicated that he

was neither shifting gears at the time nor did he

apply his brakes. In addition, he said that he had

no time to react to the developing situation, and

that he attempted to countersteer the tractor.

The tire marks and subsequent position of the

tractor and trailers as they entered the median

indicate that the tractor began to jackknife

toward the left. The curved tire mark that begins

in the right lane leading toward the median was

made by the left front (steering) axle tire and

confirms that the driver tried to countersteer.

Doubles Jackknife -- A typical jackknife

occurs when the drive axle(s) on a tractor loses

traction because of a locked or spinning wheel,

and the tractor rotates into the trailer.57 The

situation develops quickly and usually results in a

loss of control. Although a jackknife is most

often caused by excessive braking or an excess

power application for the available roadway

friction, it can also be the result of

downshifting, immediately letting off the

accelerator, or wind acting on empty trailers. The

Safety Board identified several factors that

suggest how the doubles truck may have

jackknifed.

 

57Radlinski, Richard W., The Anatomy of a Tractor

Trailer Jackknife, Vehicle Research and Test Center,

NHTSA, undated.

Figure 11 -- Gear box diagram
40

The doubles truck had a single-drive axle and

the trailers were empty. A witness observed

the truck traveling in the left lane at

approximately 60 mph about 1.3 miles south of

the accident site. The same witness observed

the doubles truck’s rear trailer swaying

approximately 6 inches in both directions. Icy

patches were present on the roadway, and the

wind was blowing from the west at about

11 mph. The doubles driver stated that the truck

had fishtailed at least three times before the

accident.

The driver stated that when he felt the trailers

(actually the drive axle) slip and push the tractor

forward and to the right, he immediately let off

the accelerator. The Safety Board considers that

the speed of the truck and the effect of the wind

on the empty trailers likely set up a harmonic

swaying motion, or oscillatory sway, in the

trailers; thus, when the drive axle wheels passed

over the icy patches, the wheels began to spin,

causing the tractor to lose both lateral and

longitudinal stability. When the driver let off the

accelerator, the tractor was pushed into a

jackknife by the trailers, and the driver was

unable to recover, even by immediately

countersteering. Therefore, the Safety Board

concludes that the initial loss of stability was the

result of wheel spin-up. (See figure 12 for a

diagram of the doubles jackknife event.)

Collision of the Doubles Truck and the

Flatbed Truck -- The doubles truckdriver said

the vehicle was still moving in a circular motion

when he hit the interior of the cab, and that he

sensed he had been stopped for 30 to 60 seconds

when he felt another impact. The southbound

flatbed truckdriver indicated that when he

realized the doubles truck was out of control, he

“went off towards the right shoulder” and the

doubles truck hit him “on the driver’s side.”

Although the flatbed driver observed the doubles

truck in the median for some period of time

before reacting to the emergency situation, the

tire marks found confirm that he tried to avoid

the collision.

The damage to the flatbed truck’s left-steer

axle indicated that it was disabled and the driver

lost all steering control during the collision. A

fluid trail left by battery acid scarring the

pavement shows the path of the flatbed truck as it

left the right shoulder and angled across the right

and left lanes before crossing the median.

The flatbed truck tractor came to rest facing

southbound in the “gore area”58 between the

northbound lanes and the ramp to CTH K. The

semitrailer came to rest across both northbound

lanes.

Collision of the Flatbed Truck and the

Passenger Van -- Witnesses placed the

passenger van traveling northbound at 50 to 55

mph in the right lane. The sole survivor in the

passenger van said that, immediately before the

collision, he looked up and saw something in the

roadway. The refrigerator truckdriver said he

saw a dark object enveloped in swirling snow

moving at him from the median at about a 45°

angle. He noticed a brief illumination of the

passenger van’s brake lights before the van

collided with the flatbed semitrailer.

The refrigerator truckdriver further indicated

that the semitrailer was still moving when the van

hit it. The damage indicates that the van hit the

right side of the front tandem wheels and landing

gear of the flatbed semitrailer. The passenger van

underrode the semitrailer and, as the two vehicles

rotated, the van left a curved scrape mark in the

pavement.

Collision of the Refrigerator Truck and

the Flatbed Truck -- The refrigerator

truckdriver said he witnessed the van collision

with the flatbed truck as he was trying to decide

in which direction to steer to avoid a collision. He

slammed on the brakes, swerved to the left, and

collided with the rear tandem wheels of the

semitrailer. The truck slid off the roadway into

the median, and the semitrailer rotated clockwise

off the roadway into the area between the

northbound lanes and the ramp for CTH K.

 

58The gore area lies immediately beyond the

divergence of two roadways; the gore area is bounded by

the edges of those roadways.
41

Figure 12 -- Jackknife diagram

Southbound

US Highway 41

Northbound

Approxim ate Scale

in Feet

0 5 ' 10' 20' 40'

W

S

E

N
42

In summary, in the early morning of

February 12, 1997, near the intersection of US

41 and CTH K, the weather was clear, the

temperature was about 16°F, the wind was

blowing about 11-12 mph from the west, and the

roadway had icy patches. The northbound

doubles truck with empty trailers was traveling at

the higher end of the speed range of 43 to 58

mph in 7th gear. When the doubles truck’s singledrive axle wheels passed over the icy patches,

they began to spin, causing the tractor to lose

stability. When the driver let off the accelerator,

the trailers pushed the tractor into a jackknife.

The driver was unable to recover and the doubles

truck crossed over the 50-foot grass median into

the southbound lanes.

The flatbed truck, traveling southbound on

US 41, unsuccessfully attempted to avoid the

collision and collided with the doubles truck, lost

control, and crossed over the median into the

northbound lanes. The northbound passenger van

struck and underrode the right front side of the

flatbed truck at the landing gear. The refrigerator

truck, also traveling northbound, swerved to

avoid but nevertheless struck the right rear side

of the flatbed truck.

The following is a discussion of the potential

countermeasures for the issues identified in this

accident.

Driver Countermeasures

Judgment of the Doubles Driver -- The

Safety Board evaluated the doubles truckdriver’s

actions in the context of the sequence of events

that led to the accident. The driver recalled that

about 15 miles north of the CF yard in

Milwaukee, he felt his trailer fishtail slightly,

which indicated to him that the roads were not in

good condition. He said that he maintained a

speed of 50 to 55 mph until he experienced

another fishtail at a point further north on the

highway. He said that he then reduced his speed

to between 35 and 40 mph.

The Safety Board considers that if the

doubles driver reduced the speed of his vehicle

after he experienced a second temporary loss of

traction, he responded appropriately. However,

based on the calculated speeds determined by the

Safety Board and confirmed by the witness

statements, it appears that the driver actually

increased his stated speeds until he completely

lost control of the vehicle.

The Safety Board considers that the doubles

driver exhibited behavior indicative of poor

judgment before the accident sequence began.

First, moving doubles, by their very nature, are

inherently less stable than single trailers,

particularly during inclement weather. They tend

to develop a lateral motion, or amplitude, that in

turn can be affected by the wind and the

coefficient of friction. Indeed, Volume 1, Section

7.1 of the January 1997 Wisconsin Commercial

Driver’s Manual advises operators of doubles

and triples to exercise caution in adverse

conditions. Specifically, the section notes that

these units have greater length and additional

dead axles to pull, and that they have a greater

likelihood of experiencing skids and traction

losses.

Second, the presence of patches of ice and

snow on the road surface would increase the

chance for a loss of control. Section 2.6 of the

Wisconsin Commercial Driver’s Manual states:

Wet roads can double stopping distances.

Reduce speed by about one third (e.g.,

slow from 55 to about 35 mph) on a wet

road. On packed snow, reduce speed by

half, or more. If the surface is icy,

reduce speed to a crawl and stop

driving as soon as you can safely do so.

[Emphasis added.]

By his own admission, the doubles driver

said that road surface conditions appeared to

deteriorate the further north he traveled. Nothing

indicates that there was any urgency to the trip to

return the empty trailers to Menasha. Yet despite

the hazardous road conditions, the doubles driver

continued traveling north at speeds not conducive

to maintaining constant traction. Therefore, the

Safety Board concludes that the doubles

truckdriver exercised poor judgment in traveling

at highway speeds on icy roadways pulling empty

trailers.

Training and Experience -- The Safety

Board examined the doubles driver’s training and

experience with regard to operating doubles. The

doubles driver had participated in and

successfully completed a 1-week (40-hour)

course on operating doubles at UPS in November
43

1995. The UPS course specifically addressed the

dynamics of doubles trailers and the operation of

doubles in adverse weather, including snow and

ice. At the conclusion of the training, the driver

demonstrated proficiency in operating doubles

and was certified to operate them. While CF does

not have its own training program that

specifically addresses doubles operations, the

firm only hires drivers who have either graduated

from an acceptable driving school or who have at

least 1 year’s experience with comparable

equipment. The doubles driver met this CF

requirement.

When hired by CF, the driver successfully

passed a road test driving doubles and was

certified by CF to operate them. Furthermore, the

driver had been driving doubles virtually every

day since he was hired by CF in October 1996

until the accident; thus, he would have operated

doubles for about 4 months in all types of

weather. He said that he had driven this

particular route about once a week since October

1996 and was comfortable with operating

doubles in this area. He had no accidents or

incidents involving doubles trailers before the

Slinger accident. Although this was the first time

that the driver had driven two empty trailers on

this route, he had driven empty doubles from

Sheboygan to Menasha. Therefore, based on his

training and experience, the Safety Board

concludes that the doubles truckdriver had

received training driving doubles equivalent to

the degree of training provided under normal

minimum industry practices.

Although the CF driver had received

doubles training consistent with industry norms,

the training did not ensure that the driver

properly recognized and responded to the

dangerous circumstances inherent in the

combination of vehicle and highway conditions

confronting him. While the Safety Board could

not determine whether training using a

simulator or a skid pad would have influenced

the judgment of the CF driver, experience in

other transportation modes suggests that

simulator training can prepare operators to

respond appropriately to hazardous conditions

and thus help prevent accidents. Therefore, the

Safety Board believes that the FHWA, NHTSA,

the American Trucking Associations (ATA), the

Motor Freight Carrier Association, and the

International Brotherhood of Teamsters should

work together to encourage the development and

use of simulator-based training for heavy truck

operators.

Corporate Culture -- The fact that CF hired

a driver with a history of speeding violations to

drive doubles trucks might seem to raise concern

about the effectiveness of the company’s hiring

practices in screening out potentially reckless

drivers. However, upon closer look, CF cannot

be censured for this decision in this circumstance.

The Safety Board’s in-depth review of the

driver’s full driving violation record indicates

that CF could not have obtained this complete

information through normal channels.

Wisconsin’s Department of Motor Vehicles

database records are normally purged after 5

years, so CF could not have learned of the 1988

and 1989 violations on the driver’s record. The

driver’s June 25, 1993, speeding citation was

dismissed after trial and so would not have

appeared on his State driving record. The

September 1996 and January 1997 violations

would not yet have appeared on the driver’s

record when CF obtained it in October 1996.

Consequently, CF could only have known of two

violations on the driver’s record when the driver

was hired, a violation rate which would not have

seemed excessive to an examiner familiar with

the trucking industry.

CF has a laudable safety record, with an

accident rate about half of the industry average.

It is CF policy to emphasize the importance of

safety, and management has established several

programs to ensure that this policy is

communicated to CF personnel.

Vehicle Countermeasures

Stability of Doubles -- The Safety Board

examined several recent truck accident studies in

light of this accident. A 1996 analysis of truck

accidents carried out for the OMC by the

University of Michigan Transportation Research

Institute indicates that most truck accidents

occur on dry pavement. A study59 recently

conducted in Indiana found that, compared to

 

59Accident Analysis and Prevention, Vol. 29, No. 1,

1997.
44

single-trailer vehicles, double-trailer vehicles

with single-drive axles had fewer crashes on dry

and wet pavements (excluding snow, ice, and

slush) and fewer crashes involving multiple

vehicles. However, this study also showed that

doubles were over-represented in crashes on road

surfaces with ice, snow, or slush. (The Indiana

study excluded accidents on ramps, which

minimized the number of rollover accidents

included in the study group.)

The over-representation of doubles in crashes

involving roadway conditions of ice, snow, and

slush is likely due to the special susceptibility of

doubles to these environmental factors. Doubles,

in general, are more reactive to wind (which is

often present under such wintry conditions) than

are single-trailer vehicles, because they have

more points of articulation, making them more

sensitive to sway. Doubles with single-drive axle

tractors are also more susceptible to low-friction

roadway surfaces, because they have fewer

contact points with the road and less effective

traction than single-trailer vehicles with dualdrive axle tractors. Therefore, the Safety Board

concludes that the greater instability of doubletrailer vehicles with single-drive axles renders

them more vulnerable to accidents on ice, snow,

and slush than single-trailer vehicles with dualdrive axles.

Research has shown that empty or lightly

loaded doubles are more susceptible to wind than

heavily loaded doubles. One study carried out at

the University of Michigan Transportation Research Institute60 demonstrated the

sensitivity of empty doubles and triples to

crosswind-induced offtracking and rollover.

This study simulated wind gusts of up to 25 mph.

The Phase 4 vehicle dynamics model simulations

conducted for the Safety Board with regard

to the Slinger accident show that, with

crosswinds of 0 to 3 mph (and all other things

being equal), the empty doubles truck would

remain stable. However, when the crosswinds

rise to 8 mph, the truck becomes only

marginally stable. Therefore, based on these

 

60MacAdam, Charles, C., “The Crosswind Sensitivity

of Unladen Doubles and Triples Combinations and Their

Susceptibility to Wind-Induced Offtracking and

Rollovers,” Supplement to Vehicle System Dynamics,

Volume 20, August 1991, pp. 432-445.

findings, the Safety Board concludes that lightly

loaded or empty doubles trucks can be

susceptible to even slight crosswinds.

Traction Control -- Jackknife can result

from the drive axle’s loss of traction caused by

locked, retarded, or spinning wheels. Although

speed was a significant factor in this accident, the

Safety Board sought to determine whether use of

a traction control device or system could have

ameliorated the wheel spin on the drive axle of

the doubles truck sufficiently to have prevented

the jackknife. The Board contracted with

University of Michigan Transportation Research

Institute staff to run Phase 4 vehicle dynamics

model simulations with input parameters from

the Slinger accident to simulate the effect that a

traction control system might have had on it.

The Phase 4 model simulations indicated

that, without traction control and under the

conditions known about the accident, the doubles

truck would have jackknifed at a speed of 58

mph. The known conditions include the

prevailing wind and road friction. The wheel spin

initiating the jackknife was caused by excess

power for the available road friction. The

inclusion of a traction control system in the

Phase 4 simulations significantly increased the

ability of the doubles truck to avoid jackknifing.

Although the simulations showed that the tractor

instability was not prevented by the traction

control mechanism, its use generally diminished

the rapidity of the loss of control. Therefore, the

Safety Board concludes that, at the speed and

under the conditions in which the accident took

place, antilock brake and traction control

technology would have given the doubles

truckdriver more time to respond to the loss of

stability.

The Safety Board considers that traction

control devices help drivers maintain stability,

particularly for single-drive axle vehicles

operating with light loads on low-friction

roadways. Truck brake manufacturers are

currently marketing traction control devices as

performance equipment and antilock brakes as

safety equipment. Although traction control

devices can be added to antilock brake systems at

minimal cost, traction control devices are not

required.
45

Because of the safety advantages that

traction control devices may contribute to the

industry, the Safety Board believes that NHTSA,

the FHWA, the ATA, the Motor Freight Carrier

Association, and the International Brotherhood of

Teamsters should work together to conduct

laboratory and truck fleet testing to assess the

safety benefits of adding traction control devices

to antilock brake systems and should report their

findings to the Safety Board. In addition, the

Safety Board believes that NHTSA, the FHWA,

the ATA, the Motor Freight Carrier Association,

and the International Brotherhood of Teamsters

should work together to encourage the trucking

industry to gain experience with traction control

devices through fleet tests. Further, the Safety

Board believes that the ATA, the Motor Freight

Carrier Association, and the International

Brotherhood of Teamsters should notify the

trucking industry of the circumstances of the

Slinger accident and develop motor carrier

guidelines for the operation of empty or lightly

loaded multiple-trailer vehicles during inclement

weather conditions.

Highway Countermeasures

Adverse Weather -- The Safety Board

examined the snow and ice removal procedures

followed by the Washington County maintenance

personnel. The personnel on duty prior to the

accident indicated that the accident area had

received two applications of salt and wetting

agent. The application rate was above the

required State contract level and within the

ranges used by other northern States. Therefore,

the Safety Board concludes that, although

Washington County more than fulfilled the

criteria in the WisDOT snow and ice removal

contract, its countermeasures did not prevent ice

from forming on the roadway.

The Safety Board found several possible

explanations as to why these countermeasures

were ineffective. The lack of natural windbreaks

(evergreen trees and shrubs) exposed the

roadway surface to winds, which may have

reduced the effectiveness of the salt and wetting

solutions. Traffic could have blown the salt and

wetting agent off the roadway before they had a

chance to melt the ice. The temperature had

dropped to around 15°F, a temperature point at

which the salt and wetting agent become less

effective, and abrasives were not applied to

provide traction.

The traditional use of salt and wetting agents

after a storm is reactive and costly. The findings

of the SHRP61 project indicate that proactive

anti-icing treatments applied before storms can

be effective. The project established that an antiicing program coupled with an RWIS could

reduce winter maintenance costs, improve travel

conditions, and help protect the environment.

Based on these findings, which were

subsequently confirmed by field tests,62 the

Safety Board concludes that new adverse weather

countermeasures and anti-icing technologies have

been shown to be effective, are readily available,

and should be aggressively adopted by Wisconsin

and other States. The Safety Board is aware that

Wisconsin tested three new anti-icing

technologies in 1997-98. (The results of the tests

were not available for inclusion in this report.)

The Safety Board believes that WisDOT should

review its policies for snow and ice removal and

(1) accelerate the use of new anti-icing

technologies, (2) consider the use of abrasives

when temperatures drop below 15°F, and (3) take

corrective action in open areas where wind could

hinder the application and effectiveness of the

salt and wetting solutions.

The Safety Board appreciates that the

FHWA, AASHTO, and the Transportation

Research Board are working together to develop

guidelines for snow and ice removal. The

guidelines could then be used as a basis to create

training materials. The next step would be to

provide the materials and training to the

government entities that are responsible for ice

and snow removal. The Safety Board believes

that the FHWA should distribute materials and

provide funding through the Local Technology

Application Program centers for the training of

State and local government officials in new antiicing technologies.

Median Barriers -- The 1996 AASHTO

Roadside Design Guide warrants for median

 

61Report No. SHRP-H-385. National Research

Council, Washington, D.C., 1994.

62Test and Evaluation Project No. 28: Anti-icing

Technology, Field Evaluation Report, FHWA-RD-97-132,

March 1998.
46

barriers on high-speed, controlled-access

roadways that have relatively flat medians

consider traffic volumes, median widths, and

accident histories. Based on the standards

provided in this guide, the ADT and median

width on US 41 in the area of the accident

indicate that median barriers are not necessary at

this location. In addition, a review of the

individual accident reports showed that this

location did not have a history of cross-median

accidents.

The AASHTO Roadside Design Guide

warrants, however, are based on a 1968 “limited

analysis of median crossover accidents”63 and

1974 research on barrier performance. Like

many highway design criteria, the warrants do

not address the volume of heavy trucks using the

roadway. For the accident area, the 1993 traffic

counts show average traffic distributions that

include 20 percent trucks. In addition, the

warrants do not take into consideration the higher

speed limits or changes in the characteristics of

the passenger vehicle fleet of recent years.

According to NHTSA, the light truck and van

weight class that includes sport utility vehicles

now constitutes 30 percent of the passenger

vehicle fleet and 40 percent of the new car

market. Therefore, the Safety Board concludes

that current AASHTO median barrier warrants

do not take into account the composition and

characteristics of the current vehicle fleet. The

Safety Board believes that AASHTO and the

FHWA should review the median barrier

warrants and revise them as necessary to reflect

changes in the factors affecting the probability of

cross-median accidents, including changes in the

vehicle fleet and the percentage of heavy trucks

using the roadways.

The Safety Board has previously expressed

concern over the incompatibility of existing

highway designs with the operating

characteristics of trucks, most recently in the

White Plains, New York, accident report.64 The

issue becomes more significant as the

percentage of trucks in the vehicle fleet

 

63Roadside Design Guide.

64Highway Accident Report -- Propane Truck

Collision with Bridge Column and Fire, White Plains, New

York, July 27, 1994 (NTSB/HAR-95/02).

increases on the National Highway System

(NHS).

On November 27, 1995, the Safety Board

issued Safety Recommendation H-95-32, which

urged the FHWA to require that the highway

geometric design and traffic operations of the

NHS be based on heavy truck operating

characteristics. In a response dated February 29,

1996, the FHWA stated that current legislation

requires a 2.5-percent minimum of innovative

barrier on Federal-aid highway projects. The

FHWA further indicated that, through

implementation guidelines, it will continue to

encourage the use of higher-performance median

barriers on the NHS. The FHWA stated that

most States have built barriers capable of

redirecting large vehicles.

Further, the FHWA stated, in a letter dated

March 27, 1997, that it is in basic agreement

with the Board on this issue, in that consideration

must be given to heavy vehicles when developing

standards for the NHS. The FHWA stated that,

acting on this belief, it is supporting research

under the NCHRP and its own research program

to develop “the analysis tools and bases for

highway standards that address the effects and

requirements of heavy vehicles.”

In an October 7, 1997, letter to the FHWA,

the Safety Board stated:

Encouraging innovative barriers is a

good start in the effort to provide

consistent and higher standards for large

trucks on the NHS and [the Board] looks

forward to other improvements in design

that address the operating characteristics

of large trucks.

In addition, the Board classified Safety

Recommendation H-95-32 “Open--Acceptable

Response.”

Reporting of Cross-median Accidents --

One of the criteria for determining the need for

median barriers in any location is a history of

cross-median accidents at that location. Median

barriers can prevent and ameliorate accidents,

and such barriers might have made a difference

in the Slinger accident. Accurate and complete

data on crossover accidents are important
47

because they help ensure that median barriers are

installed where they are needed. Yet most States

do not have a cross-median data element on their

official accident reporting forms. Consequently,

as demonstrated by investigation of the Florida

and Wisconsin accidents cited earlier in this

report and examination of the FARS data, this

information is not readily available.

Because reporting forms typically lack a

cross-median data element, individual accident

reports must be reviewed or other codes, such as

head-on collisions, must be employed to capture

cross-median accident data. In addition, as in the

Jacksonville, Florida, case, cross-median data

may be coded as “other,” making it very difficult

to separate from unrelated data. Therefore, the

Safety Board concludes that cross-median

accidents are probably underreported because

most accident reporting forms do not have a

separate data element for them, and using other

reporting elements to capture cross-median

accidents may not result in full and accurate

accounting.

NHTSA, the FHWA, and the NAGHSR are

currently developing the Guideline for Minimum

Uniform Crash Criteria. The Safety Board

believes that, because of the importance of this

issue, NHTSA, the FHWA, and the NAGHSR

should include a data element for cross-median

accidents in the Guideline for Minimum Uniform

Crash Criteria.

Survivability Countermeasures

Crash Forces -- In many cases, the

survivability of a crash is directly related to the

crash pulse or acceleration time history of the

vehicle(s) during the collision. The most accurate

method of determining the crash pulse is use of

an accelerometer, or crash pulse recording

device. Unfortunately, the airbag ECM on the

model of passenger van involved in this accident

did not require the storage of a crash pulse, and

therefore none was recorded.

The Safety Board could not calculate the

crash pulse and delta-v of the passenger van’s

collision with the flatbed truck. Crash pulse data

would have been particularly useful to this

accident investigation. An accurate recording of

the actual deceleration of the van would have

permitted a more complete analysis of the forces

experienced by the occupants and the forces they

would have experienced had they been

appropriately restrained. This information would

have allowed investigators to make a more

definitive analysis about the potential

survivability of the accident for each of the

fatally injured passengers.

The Safety Board addressed the desirability

of having crash pulse data for vehicle crashes

during its Air Bag Forum.65 On July 1, 1997, the

Safety Board issued the following safety

recommendation to NHTSA:

H-97-18

Develop and implement, in conjunction

with the domestic and international

automobile manufacturers, a plan to

gather better information on crash pulses

and other crash parameters in actual

crashes, utilizing current or augmented

crash sensing and recording devices.

NHTSA responded on July 7, 1997, and

indicated that it was working with automobile

manufacturers to identify crash vehicles equipped

with special devices that can record crash pulses

and read the crash device recorder. NHTSA also

stated that it was developing an Automated

Collision Notification (ACN) system designed to

reduce the response time for emergency medical

assistance. According to NHTSA, the system will

have the capability to sense (via onboard

accelerometers, in addition to those used for air

bag deployment) that the vehicle has been in a

collision.

The Safety Board responded on February

12, 1998, that it is “concerned that the provision

of the crash pulse recording has been limited in

quantity and that it is not clear how the

information from the ACN system will be used.”

Safety Recommendation H-97-18 was classified

“Open--Unacceptable Response” because no plan

for gathering information on actual crashes with

current or augmented crash sensing and recording

devices had been presented.

 

65NTSB/RP-97/01.
48

On-board Recorders -- Another tool in accident

investigation and reconstruction is the on-board

recorder. On-board recorders are also used by the

trucking industry as management tools for

carrying out speed control and incentive systems

for drivers. Although the Slinger doubles truck

had an ECM, it did not have on-board recording

devices, which are optional. Consequently, the

truck’s actual speed at the time of the collision

was not readily available.

“Automatic information recording devices” is

a safety issue on the Safety Board’s “Most

Wanted” list. The Safety Board considers that

adequate on-board recording devices are

necessary in all modes of transportation because

information from them can be used to identify

safety trends, develop corrective actions, and

conduct more efficient accident investigations.

Cockpit voice recorders and flight data recorders,

or black boxes, have been on commercial

airliners for years. Since 1993, event recorders

have also been required on trains. Through

Safety Recommendations R-96-46 and -47,

the Safety Board recommended that the Federal

Transit Administration and the American Public

Transit Administration develop guidelines for

event monitoring/recording devices for rapid

transit cars and urge transit agencies to install

such devices on new and rehabilitated cars.

Regarding marine transportation, the Safety

Board has for more than 20 years recommended

the use of voyage event recorders for marine

accident reconstruction.

The Safety Board has also made

recommendations regarding recorders for

highway trucking transport. Although the

recommendation was primarily aimed at reducing

fatigue-related accidents, in 1990,66 the Safety

Board issued Safety Recommendation H-90-28

to the FHWA:

H-90-28

Require automated/tamper-proof onboard recording devices, such as

tachographs or computerized logs, to

 

66Safety Study -- Fatigue, Alcohol, Other Drugs, and

Medical Factors in Fatal-to-the-Driver Heavy Truck

Crashes (NTSB/SS-90/01).

identify commercial truckdrivers who

exceed hours-of-service regulations.

The Safety Board reiterated Safety

Recommendation H-90-28 in its 1995 study on

truckdriver fatigue,67 explaining that the intent of

the recommendation was to provide a tamperproof mechanism that could be used to enforce

the hours-of-service regulations, rather than

relying on drivers’ handwritten logs. In a

February 1997 response, the FHWA

acknowledged that on-board recording devices

will eventually be an important tool for

monitoring the hours of service of commercial

motor vehicle drivers. However, the FHWA

stated that “the FHWA position is that the

benefits and practicality of on-board recorders

must be firmly established before rulemaking

ensues.” The current status of Safety

Recommendation H-90-28 is “Open--

Unacceptable Action.”

Therefore, because the FHWA has not yet

effectively acted on Safety Recommendation H90-28, the Safety Board believes that the

trucking industry associations should advise their

members to equip their commercial vehicle fleets

with automated and tamper-proof on-board

recording devices, such as tachographs or

computerized recorders, to identify information

concerning both driver and vehicle operating

characteristics.

Occupant Injuries and Seat Belt Use -- In

any given vehicle collision, three collisions

actually take place: the vehicle’s collision, the

occupant’s collision, and the human body’s

internal collision.68 The first collision is the

vehicle’s collision with an external object. But

after the vehicle crushes and comes to a stop, the

occupant continues to move. Therefore, the

second collision is the occupant’s collision with

objects inside the vehicle, the vehicle’s structure,

other occupants, or cargo. Then, even after the

occupant’s body comes to a complete stop, the

occupant’s internal organs continue to move.

Consequently, the third collision is the

 

67Safety Study -- Factors That Affect Fatigue in

Heavy Truck Accidents (NTSB/SS-95/01).

68Sudden Impact: An Occupant Protection Fact Book,

NHTSA, DOT HS 807743, July 1991, pp. 4-5.
49

internal organs’ collision with other organs or the

skeletal system.

Lap/shoulder belts are vehicle occupants’

first line of defense in the second and third

collisions of the sequence. Restraints hold the

occupants in place, allowing them to stop as the

vehicle is stopping, or to “ride down” the

collision. Restraints also distribute the forces of

rapid deceleration over larger and stronger parts

of the body.

The Safety Board examined the passenger

van damage, the autopsy reports, and the medical

records of the passenger van occupants. The

Board found evidence of injury patterns

consistent with seat belt use for the driver of the

van. In addition, rescue personnel stated that the

driver and the right front passenger were belted

when the accident occurred. However, the

intrusion into the van precluded their survival.

The fatal injuries sustained by the driver and

right front passenger resulted either from the loss

of occupant space because of the intrusion into

the van, from the secondary collisions within the

vehicle, or from the impact with the flatbed

trailer as it intruded into the vehicle.

The Safety Board found no evidence of

restraint use by the passengers in the rear of the

van. The surviving passenger stated that none of

the back seat passengers had been using seat

belts. Although the Board found no marks on any

other restraint system in the rear of the van, it

found plastic transfers from the D-ring on the

belt for the left outboard seating position of row

4. The passenger seated directly behind this

position (the left outboard seating position of row

5) sustained a partial amputation of the left arm

at the shoulder. The Safety Board considers that

the plastic transfers from the D-ring found on the

belt for the left outboard position of row 4

resulted from this passenger’s left arm interacting

with that belt and loading it as he moved forward

relative to the vehicle during the collision.

The van survivor, who had been seated in the

middle of the fourth row, sustained injuries to his

legs and his arm. He told the Safety Board that

the cargo in the van had been stored several feet

in front of him. The interaction between the

survivor and the cargo and the interaction of his

legs with the interior of the van probably slowed

him gradually, allowing him to ride down the

collision. As a result, the injuries to his head and

chest were significantly less severe than those of

the other occupants of the van.

The Safety Board’s evaluation of autopsy

reports and medical records indicated that the

fatal injuries sustained by the passengers in the

rear of the van resulted from secondary collisions

with the interior of the van. The short distances

over which these secondary collisions occurred

resulted in greater forces and decelerations being

experienced by these passengers than by the

vehicle itself. The Safety Board considers that the

use of the available lap/shoulder restraint

systems in rows 4 and 5 would have reduced

such secondary impact forces.

During a collision, a vehicle experiences

crushing deformation that lengthens the duration

of the impact and substantially decreases the

peak and average forces experienced by the

undeformed portions of the vehicle. Unrestrained

occupants do not benefit from this deformation,

as they continue moving until they contact

interior vehicle surfaces. Unless some cushion is

provided by the vehicle interior, unrestrained

occupants can experience deceleration forces

many times greater than those experienced by the

vehicle. On the other hand, restrained occupants,

particularly those properly using lap/shoulder

restraint systems, do not move significantly in

relation to the vehicle interior; they experience

deceleration forces similar to those experienced

by the vehicle itself.

In this collision, the forward van structure

experienced several feet of deformation during

the underride of the van beneath the flatbed

trailer. Because the occupants in the rear of the

van did not use their restraint systems, they did

not benefit from the reduction in peak forces

associated with such deformation.

A number of other variables influenced the

probability of survival for a belted occupant.

These variables include occupant age, health, and

position relative to the belt system before the

collision; occupant impact with loose objects

within the vehicle; and occupant motion relative

to the restraint systems. However, the fact that

one individual survived this accident
50

demonstrates that the crash forces the vehicle

experienced were not inherently fatal. Although it

cannot conclude with certainty that the

passengers would have survived had they worn

the lap/shoulder belt restraint systems, the Safety

Board concludes that the use of the available

lap/shoulder belt restraint systems by the

occupants of the passenger van would have

significantly decreased the severity of their

injuries and thereby increased the probability of

their survival.

Wisconsin Seat Belt Use Law -- The

Safety Board could not determine why the

occupants of the rear of the van were not wearing

the available restraints. Although he said he knew

Wisconsin had a mandatory seat belt law, the

survivor did not tell the Board why he and the

other passengers in the rear of the van were not

wearing the available restraints.

The Wisconsin seat belt MUL is a secondary

enforcement law that is enforceable for seating

positions with lap/shoulder belts only. Although

Wisconsin is one of the few States that allows a

court to consider evidence of failure to wear a

seat belt, it permits mitigation of only 15 percent

of the damages that may be recovered by a

plaintiff who failed to wear a seat belt. The

Wisconsin seat belt use rate is approximately 6

percent lower than the current national average.

Research has shown that States and countries

with stricter seat belt use laws have higher seat

belt use rates. Consequently, the Safety Board

considers that Wisconsin should enact stronger

seat belt use laws to increase its seat belt use

rate. The Board has previously recommended

that Wisconsin and other States enact strong

legislation regarding child restraint and seat belt

use. In fact, stricter MULs have been on the

Safety Board’s 1995, 1996, and 1997 “Most

Wanted” lists. (See appendix F, Safety Board

Recommendations on Mandatory Seat Belt Use

Laws, for more details.)

On June 20, 1995, the Board issued Safety

Recommendation H-95-13 to the States (and the

District of Columbia) that had secondary

enforcement of mandatory seat belt laws and the

States without MULs. It recommended that these

jurisdictions:

H-95-13

Enact legislation that provides for

primary enforcement of mandatory

safety belt laws. Consider provisions

such as adequate fine levels and the

imposition of driver license penalty

points.

Wisconsin did not respond to Safety

Recommendation H-95-13. Following the Air

Bag Forum held on July 1, 1997, the Safety

Board reclassified Safety Recommendation H95-13 “Closed--Acceptable Action/Superseded”

and issued the following new safety

recommendation to the Governors and legislative

leaders of the 50 States and U.S. Territories, and

the mayor and chairman of the council of the

District of Columbia:

H-97-2

Enact legislation that provides for

primary enforcement of mandatory seat

belt use laws, including provisions such

as the imposition of driver license

penalty points and appropriate fines.

Existing legal provisions that insulate

people from the financial consequences

of not wearing a seat belt should be

repealed. (Supersedes H-95-13.)

Wisconsin has not responded to Safety

Recommendation H-97-2. Consequently, the

Safety Board reiterates Safety Recommendation

H-97-2 to the State of Wisconsin.

Emergency Response

Once a witness had placed a 911 call

notifying authorities of this accident, an officer

was on scene within 3 minutes and the command

vehicle was on scene within about 8 minutes.

The Flight for Life helicopter from Milwaukee

landed at the scene within 45 minutes,

and the first victim from the van was transported

by ambulance to an area hospital 59 minutes

from the time of notification.

The last victim from the van was not

transported by helicopter to a trauma center

until 2 hours and 8 minutes after the

notification, but much of the delay occurred

because medical personnel decided to stabilize
51

the patient before transporting him. The Safety

Board found that the medical personnel acted

appropriately in delaying transport of the victim.

The Safety Board further considers that the delay

did not adversely impact the victim’s survival.

The Safety Board also considers that the

number of rescue personnel and the amount of

equipment dispatched were appropriate for the

number of vehicle occupants and the severity of

the accident. Therefore, the Safety Board

concludes that the emergency response was

effective and well coordinated.
52

Findings

1. No alcohol use, drug use, fatigue, or vehicle

mechanical defects contributed to this

accident.

2. At the time and in the vicinity of the accident,

the wind was blowing at about 11 to 12

mph from the west.

3. At the time and in the vicinity of the accident,

the road had patches of ice.

4. Although the doubles truck was found in 6th

gear after the accident took place, it had been

traveling at the upper limits of the calculated

speed estimate of 43 to 58 mph, and

therefore it had been in 7th gear.

5. The initial loss of stability was the result of

wheel spin-up.

6. The doubles truckdriver exercised poor

judgment in traveling at highway speeds on

icy roadways pulling empty trailers.

7. The doubles truckdriver had received training

driving doubles equivalent to the degree of

training provided under normal minimum

industry practices.

8. The greater instability of double-trailer

vehicles with single-drive axles renders them

more vulnerable to accidents on ice, snow,

and slush than single-trailer vehicles with

dual-drive axles.

9. Lightly loaded or empty doubles trucks can

be susceptible to even slight crosswinds.

10. At the speed and under the conditions in

which the accident took place, antilock brake

and traction control technology would have

given the doubles truckdriver more time to

respond to the loss of stability.

11. Although Washington County more than

fulfilled the criteria in the Wisconsin

Department of Transportation snow and ice

removal contract, its countermeasures did not

prevent ice from forming on the roadway.

12. New adverse weather countermeasures and

anti-icing technologies have been shown to

be effective, are readily available, and should

be aggressively adopted by Wisconsin and

other States.

13. Current American Association of State

Highway and Transportation Officials

median barrier warrants do not take into

account the composition and characteristics

of the current vehicle fleet.

14. Cross-median accidents are probably

underreported because most accident

reporting forms do not have a separate data

element for them, and using other reporting

elements to capture cross-median accidents

may not result in full and accurate

accounting.

15. The use of the available lap/shoulder belt

restraint systems by the occupants of the

passenger van would have significantly

decreased the severity of their injuries and

thereby increased the probability of their

survival.

16. The emergency response was effective and

well coordinated.

Probable Cause

The National Transportation Safety Board

determines that the probable cause of the

accident was the doubles truckdriver’s lack of

judgment in driving too fast for the configuration

of his truck under the hazardous highway

weather conditions. Contributing to the severity

of the injuries and the reduced potentiality for

survival was the lack of restraint use by the

unrestrained occupants of the passenger van.

CONCLUSIONS
53

As a result of its investigation, the National

Transportation Safety Board makes the following

safety recommendations:

-- to the Federal Highway Administration:

Work, together with the National

Highway Traffic Safety Administration,

the American Trucking Associations, the

International Brotherhood of Teamsters,

and the Motor Freight Carrier

Association, to encourage the

development and use of simulator-based

training for heavy truck operators. (H98-8)

Work, together with the National

Highway Traffic Safety Administration,

the American Trucking Associations, the

International Brotherhood of Teamsters,

and the Motor Freight Carrier

Association, to conduct laboratory and

truck fleet testing to assess the safety

benefits of adding traction control

devices to antilock brake systems and

report your findings to the National

Transportation Safety Board. (H-98-9)

Work, together with the National

Highway Traffic Safety Administration,

the American Trucking Associations, the

International Brotherhood of Teamsters,

and the Motor Freight Carrier

Association, to encourage the trucking

industry to gain experience with traction

control devices through fleet tests. (H98-10)

Distribute materials and provide funding

through the Local Technology

Application Program centers for the

training of State and local government

officials in the new anti-icing

technologies. (H-98-11)

Review, with the American Association

of State Highway and Transportation

Officials, the median barrier warrants

and revise them as necessary to reflect

changes in the factors affecting the

probability of cross-median accidents,

including changes in the vehicle fleet and

the percentage of heavy trucks using the

roadways. (H-98-12)

Include a data element for cross-median

accidents in the Guideline for Minimum

Uniform Crash Criteria, which you are

developing with the National Highway

Traffic Safety Administration and the

National Association of Governors’

Highway Safety Representatives. (H98-13)

-- to the National Highway Traffic Safety

Administration:

Work, together with the Federal

Highway Administration, the American

Trucking Associations, the International

Brotherhood of Teamsters, and the

Motor Freight Carrier Association, to

encourage the development and use of

simulator-based training for heavy truck

operators. (H-98-14)

Work, together with the Federal

Highway Administration, the American

Trucking Associations, the International

Brotherhood of Teamsters, and the

Motor Freight Carrier Association, to

conduct laboratory and truck fleet testing

to assess the safety benefits of adding

traction control devices to antilock brake

systems and report your findings to the

National Transportation Safety Board.

(H-98-15)

Work, together with the Federal

Highway Administration, the American

Trucking Associations, the International

Brotherhood of Teamsters, and the

Motor Freight Carrier Association, to

encourage the trucking industry to gain

experience with traction control devices

through fleet tests. (H-98-16)

RECOMMENDATIONS
54

Include a data element for cross-median

accidents in the Guideline for Minimum

Uniform Crash Criteria, which you are

developing with the Federal Highway

Administration and the National

Association of Governors’ Highway

Safety Representatives. (H-98-17)

-- to the National Association of Governors’

Highway Safety Representatives:

Include a data element for cross-median

accidents in the Guideline for Minimum

Uniform Crash Criteria, which you are

developing with the National Highway

Traffic Safety Administration and the

Federal Highway Administration. 

(H-98-18)

-- to the American Trucking Associations, the

Motor Freight Carrier Association, and the

International Brotherhood of Teamsters:

Work, together with the Federal

Highway Administration and the

National Highway Traffic Safety

Administration, to encourage the

development and use of simulator-based

training for heavy truck operators. (H98-19)

Work, together with the National

Highway Traffic Safety Administration

and the Federal Highway Administration,

to conduct laboratory and truck fleet

testing to assess the safety benefits of

adding traction control devices to

antilock brake systems and report your

findings to the National Transportation

Safety Board. (H-98-20)

Work, together with the National

Highway Traffic Safety Administration

and the Federal Highway Administration,

to encourage the trucking industry to

gain experience with traction control

devices through fleet tests. (H-98-21)

Notify the trucking industry of the

circumstances of the multiple vehicle

crossover accident that took place in

Slinger, Wisconsin, on February 12,

1997, and develop motor carrier

guidelines for the operation of empty or

lightly loaded multiple-trailer vehicles

during inclement weather conditions. (H98-22)

Advise your members to equip their

commercial vehicle fleets with automated

and tamper-proof on-board recording

devices, such as tachographs or

computerized recorders, to identify

information concerning both driver and

vehicle operating characteristics. (H98-23)

-- to the American Association of State Highway

and Transportation Officials:

Review, with the Federal Highway

Administration, the median barrier

warrants and revise them as necessary to

reflect changes in the factors affecting

the probability of cross-median

accidents, including changes in the

vehicle fleet and the percentage of heavy

trucks using the roadways. (H-98-

24)

-- to the Wisconsin Department of

Transportation:

Review your policies for snow and ice

removal and 1) accelerate the use of new

anti-icing technologies, 2) consider the

use of abrasives when temperatures drop

below 15°F, and 3) take corrective action

in open areas where wind could hinder

the application and effectiveness of the

salt and wetting solutions. (H-98-

25)

-- to the Independent Truckers and Drivers

Association, the National Private Truck Council,

and the Owner-Operators Independent Drivers

Association, Inc.:

Advise your members to equip their

commercial vehicle fleets with automated

and tamper-proof on-board recording

devices, such as tachographs or

computerized recorders, to identify

information concerning both driver and

vehicle operating characteristics. (H98-26)
55

Also as a result of its investigation of this

accident, the National Transportation Safety

Board reiterates the following safety

recommendation to the State of Wisconsin:

H-97-2

Enact legislation that provides for

primary enforcement of mandatory seat

belt use laws, including provisions such

as the imposition of driver license

penalty points and appropriate fines.

Existing legal provisions that insulate

people from the financial consequences

of not wearing a seat belt should be

repealed. (Supersedes H-95-13.)

BY THE NATIONAL TRANSPORTATION SAFETY BOARD

JAMES E. HALL

Chairman

ROBERT T. FRANCIS II

Vice Chairman

JOHN A. HAMMERSCHMIDT

Member

JOHN J. GOGLIA

Member

GEORGE W. BLACK, JR.

Member

July 24, 1998

57

APPENDIX A -- Investigation and Hearing

Investigation

The National Transportation Safety Board was notified of the Slinger, Wisconsin, accident about

11 a.m., February 12, 1997. An investigative team was dispatched with members from the Washington,

D.C.; Atlanta, Georgia; Parsippany, New Jersey; Gardena, California; and Arlington, Texas, offices. The

team members arrived on the scene at various times during the evening of February 12, 1997. Groups

were established to investigate the human performance aspects; the highway, vehicle, and survival

factors; and the motor carrier operations.

Participating in the investigation were representatives of the Federal Highway Administration, the

Wisconsin Department of Transportation, the Washington County Sheriff’s Department, the Slinger

Police Department, the Slinger Fire Department, the Wisconsin State Patrol, Consolidated Freightways,

Inc., McFaul Transport, Inc., Glandt/Dahlke, Inc., May Fair Rent A Car, Inc., and SIVA Truck Leasing.

Public Hearing or Depositions

No public hearing was held, and no depositions were taken during the investigation.

59

APPENDIX B -- Injury Information

Injuries in this accident have been coded according to the revised 1990 Abbreviated Injury Scale of

the American Association for Automotive Medicine, which is the standard system of assessing injury

severity.

TYPE Doubles

Truck

Driver

Flatbed

Truck

Driver

Van

Driver

Van

Passengers

Refrigerator

Truck

Driver

TOTAL

AIS-1 Minor 1 1 2

AIS-2 Moderate

AIS-3 Serious

AIS-4 Severe

AIS-5 Critical 1 1

AIS-6

Unsurvivable

17 8

AIS-0 None 1 1

AIS-9 Unknown

TOTAL 1 1 1 8 1 12

61

APPENDIX C -- Roadway Weather Information System

WEATHER DATA TABLE1

A: S = Snow, I = Ice, C = Chemical, D = Dry, and W = Wet.

B: Chemical Factor = percent of brine in solution (salt and wetting agent).

C: Accident occurred at approximately 5:52 a.m.

 

1

The Scan-cast pavement sensors and a weather monitoring station are located approximately 10 miles east of the accident

site, on U.S. Route 41 near the intersection of U.S. Route 45 and State Highway 60. These values do not imply that similar

conditions existed on U.S. Route 41.

Date Time

(24 hr.

clock)

StatusA Chemical

FactorB

%

Surface

Temp.

(°F)

SubSurface

Temp.

(°F)

Air

Temp.

(°F)

Dew

Point

(°F)

Relative

Humidity

%

Precip.

Y/N

Wind

Direction/

Speed

(mph)

2/11/97 19:38 D -- 25 30 22 15 75 Y SW/12

20:05 S/I 0 25 30 22 16 77 Y SW/10

20:20 S/I 01 24 30 21 16 81 Y SW/11

20:36 C/W 04 24 30 21 17 86 Y SW/8

21:07 C/W 11 23 30 21 19 90 Y SW/14

22:14 S/I 10 22 30 20 18 93 Y SW/12

23:33 S/I 0 23 30 19 18 96 Y SW/12

2/12/97 00:00 S/I 0 23 30 19 18 96 Y SW/12

02:03 S/I 0 22 30 19 18 96 Y W/10

02:46 S/I 0 20 30 19 18 95 Y W/11

02:54 S/I 0 20 30 18 17 95 Y W/14

03:20 S/I 0 18 30 18 17 95 Y W/9

03:33 S/I 0 18 30 17 16 95 Y W/9

04:01 S/I 0 19 30 17 16 95 Y W/9

04:29 S/I 0 18 30 17 16 94 Y W/12

04:47 S/I 0 17 30 16 15 94 Y W/10

04:55 S/I 0 17 30 16 15 94 Y NW/10

05:03 S/I 0 16 30 16 15 94 Y W/11

05:52C -- -- -- -- -- -- -- -- --

06:02 S/I 0 15 30 14 12 92 Y W/10

06:03 S/I 0 15 30 14 12 92 N W/10

63

APPENDIX D -- Median Barrier Warrants

According to the American Association of State Highway and Transportation Officials (AASHTO), a

median barrier is “a longitudinal barrier most commonly used to separate opposing traffic on a divided

highway.”1

 Warrants for the installation of barriers are usually based on combinations of average daily

traffic (ADT) and median widths that fall within the ranges shown in the table below.

Median Barrier Warrants for Freeways and Expressways

0/0 2 4 6 8 10 12 14 16 18 20

Median width (meters)

*Based on a 5-year projection.

Light shaded area indicates - evaluate need for barrier

Clear area indicates - barrier optional

Darker shaded area indicates - barrier not normally

considered

The median at the accident site was 50 feet wide (15.2 meters) and the ADT was about 25,000

vehicles. This point, marked roughly with the black “square” on the chart above, falls within the shaded

area where barriers are not normally considered. AASHTO recommends that where the ADT is less than

20,000 and the median widths are within the optional areas of the chart above, a barrier is only warranted

if the area has a history of median crossover accidents. Wisconsin Department of Transportation accident

statistics do not show a history of median crossover accidents in the area of the Slinger accident site.

 

1

AASHTO, Roadside Design Guide, 1996.

80

70

60

50

40

30

20

10

65

APPENDIX E -- Safety Board Phase 4 Computer Runs

 RUN DESCRIPTION RESULT

1 Baseline Accident Run; 58 mph; throttle on, then

released; no tractor slip control; driver counter-steer

to right; 11 mph wind from west; peak tire/road

friction = 0.17, slide = 0.10

Jackknife to left

2 Same as #1, but at 53 mph Jackknife to left, then right

3 Same as #1, but at 48 mph Stable

4 Same as #2, but clutch disengaged at throttle

release

Jackknife to left, then back to

right

5 Same as #1, but clutch disengaged Slower jackknife to left

6 Same as #1, but peak tire/road friction = 0.2 Stable

7 Same as #6, but no throttle release Slow development of

jackknife to left

8 Same as #1, but slip control max = 0.1 at tractor rear Jackknife to left then back to

right

9 Same as #8, but clutch also disengaged Similar to #8

10 Same as #8, but truck speed reduced to 53 mph Stable

11 Same as #10, with no throttle release Fishtail left then right, then

final slow jackknife to left

12 Same as #10, but slip control = 0.2 max on tractor

rear

Fishtail left-right-left

13 Baseline #1, but NO crosswind Stable

14 Baseline #1, but crosswind = 3 mph, no throttle

release

Stable

15 Baseline #1, but crosswind = 8 mph, no throttle

release

Marginally stable

16 Baseline #1, but initial throttle setting reduced 25% Jackknife to left and

recovery

17 Same as #16, but throttle not released Jackknife to left

18 Same as #14, but increased throttle setting causing

speed pickup

Slow jackknife to left at end

of run

19 Same as #18, but slip control max = 0.2 on tractor

rear axle

Slow jackknife to left

20 Same as #18, but slip control max = 0.1 on tractor

rear axle

Initial fish-tailing, followed by

eventual slow jackknife to

right as speed increases

67

APPENDIX F-- Safety Board Recommendations on Mandatory Seat

Belt Use Laws

The following is an excerpt from a July 1, 1997, Safety Board letter, regarding Safety

Recommendations H-97-1 through -6, which were issued to the Governors and Legislative Leaders of the

50 States and U.S. Territories, and the Mayor and Chairman of the Council of the District of Columbia.

Seat Belt Use Legislation

According to the National Highway Transportation Administration (NHTSA), lap/shoulder belts,

when used properly, reduce the risk of fatal injury to front seat passenger vehicle occupants by

45 percent. Increasing the seat belt use rate is the most effective way of cutting the highway death toll.

According to NHTSA, increasing the nationwide seat belt use rate from the present 68 percent to

85 percent would prevent an estimated 4,194 fatalities and 103,518 injuries annually. This reduction in

injuries and deaths would result in an economic savings of about $6.7 billion annually. A 90 percent use

rate would prevent 5,536 fatalities and 132,670 injuries and save $8.8 billion annually. Seat belts are the

most effective means of reducing fatalities and serious injuries when traffic crashes occur; they are

estimated to save 9,500 lives in the United States each year.

The Safety Board has previously recommended that the States enact strong legislation regarding

child restraint and seat belt use. In 1991, the Board recommended that the 12 States without mandatory

restraint use laws (MULs) enact legislation that would require occupants of all passenger cars, vans, and

light trucks to use lap/shoulder belt systems in seating positions equipped with such belt systems. In

1995, the Board recommended that the States enact legislation that provides for primary enforcement of

mandatory seat belt use laws. Because of the importance of this issue, the Board placed this

recommendation on its “Most Wanted” list of safety improvements.1 Today, 49 States, the U.S.

Territories, and the District of Columbia have MULs.2

Of the 49 States with mandatory use laws, only 11 States, the U.S. Territories, and the District of

Columbia have provisions for primary enforcement, which means that a vehicle can be stopped solely for

a seat belt violation.3

 In the other 38 States, the law is a secondary enforcement measure, which means

that an officer can cite a motorist for a belt-use violation only if the officer has already stopped the

vehicle for another infraction. As a result of the Safety Board’s 1996 study on child passenger protection,

the Board reiterated the following recommendation to the States without primary enforcement. The

recommendation was originally issued in 1995:

Enact legislation that provides for primary enforcement of mandatory safety belt laws. Consider

provisions such as adequate fine levels and the imposition of driver license penalty points.

(H-95-13)

In 1996, 82 percent of the States with primary law enforcement had seat belt use rates of 68 percent

or higher, but only 27 percent of the States with secondary law enforcement had seat belt use rates as

 

1

The purpose of the “Most Wanted” list, which is drawn up from safety recommendations previously issued, is to bring

special emphasis to the safety issues the Board deems most critical.

2

New Hampshire does not mandate seat belt use beyond age 12.

3

Maryland and Oklahoma passed primary seat belt enforcement laws that become effective on October 1 and November 1,

1997, respectively.
68 APPENDIX F

high. Seat belt use rates average about 15 percent higher in States with primary enforcement laws than in

States with secondary enforcement laws.

The Safety Board recognizes and commends the States’ efforts and the efforts of the highway safety

community to encourage the States to address this important issue. However, because of the continued

loss of lives on the Nation’s highways, and the consequential cost in health care, taxes, and public

assistance, States must find additional ways to encourage seat belt use. Experience has shown that strong

legislative initiatives, dedicated and highly visible enforcement, and public information campaigns are

the most effective methods to increase seat belt use. States and countries where the usage rate has

remained high provide valuable insight on which methods work.

Use rates in Australia, Canada, and Germany exceed 90 percent, whereas use rates in many western

European countries exceed 80 percent. Seat belt use laws in these countries typically allow primary

enforcement and also cover occupants of light trucks and vans in addition to passenger cars. Fines in

these countries are generally higher than in the United States, and some jurisdictions assess demerit

points against driver licenses for violating seat belt use laws.

The fines in the United States typically range from $10 to $25; two States and the District of

Columbia assess a fine of $50 or more. Only the District of Columbia assesses penalty points for seat belt

violations.4

 In Australia, violators typically are fined $150 to $200 and receive three demerit points.5 In

addition, the courts can impose fines up to $2,000 and/or 6 months imprisonment. In Canada, violators

also receive demerit points and high fines. Europeans are encouraged to wear seat belts because full

insurance coverage will not be available if they are involved in an accident in which they are not belted.

Societal attitudes in the United States must change with regard to seat belt use. In other countries,

drivers are held legally responsible for their actions. In 29 States and the District of Columbia, however,

evidence of the failure to wear a seat belt is inadmissible in a court of law.6

 In seven other States, the law

only allows mitigation of a very small percentage – typically 5 percent – of the damages that may be

recovered by a plaintiff who failed to wear seat belts.7

 An occupant who fails to wear a seat belt is not

exercising reasonable care for his/her own safety. Any person who fails to wear the available

lap/shoulder belt should be legally responsible for any enhancement of injuries caused by such failure. It

is inconsistent public policy for State governments to be insulating people from the financial

consequences of not wearing seat belts at the same time that the Federal government is aggressively

trying to increase seat belt use rates. Further, government at all levels incurs significant costs resulting

from injuries to unbelted vehicle occupants.8

 Thus, the Safety Board believes that the States, U.S.

Territories, and the District of Columbia should enact legislation that provides for primary enforcement

of mandatory seat belt use laws, including provisions such as the imposition of driver license penalty

 

4

Effective October 1 and November 1, 1997, the District of Columbia will assess two penalty points and a $50 fine for a

seatbelt violation.

5

The driver license is revoked in Australia when 12 demerit points accumulate.

6

The 29 States are Alabama, Connecticut, Delaware, Georgia, Idaho, Illinois, Kansas, Kentucky, Louisiana, Maine,

Maryland, Massachusetts, Minnesota, Mississippi, Montana, Nevada, New Mexico, North Carolina, Oklahoma, Pennsylvania,

Rhode Island, South Carolina, South Dakota, Texas, Utah, Vermont, Virginia, Washington, and Wyoming.

7

The seven States and the percentage limitation on mitigation follow: Iowa, 5 percent; Michigan, 5 percent; Missouri, l

percent; Nebraska, 5 percent; Oregon, 5 percent; West Virginia, 5 percent; and Wisconsin, 15 percent.

8

The Federal share of the medical costs of crashes is about 60 percent of total public costs. If all States passed standard

enforcement laws and seat belt use increased to 85 percent, Federal taxpayers would save almost $1 billion a year in medical

costs. That saving is in addition to the amount States would save. (National Highway Traffic Safety Administration, 1996.

Economic Cost to Motor Vehicle Crashes, 1994. NHTSA Tech. Rep. DOT HS 808 425. Washington, D.C.)
APPENDIX F 69

points and appropriate fines. Existing legal provisions that insulate people from the financial

consequences of not wearing a seat belt should be repealed. In view of the foregoing, the Board also

reclassifies Safety Recommendation H-95-13 “Closed--Acceptable Action/Superseded” by this new

recommendation.

North Carolina has demonstrated that a primary enforcement seat belt law in combination with a

dedicated and visible seat belt traffic enforcement program increases restraint use and saves lives; the

State reported a reduction of 100 fatalities in the first year following its “Click It or Ticket” occupant

restraint enforcement campaign. The Safety Board is aware of several other seat belt enforcement

programs in addition to the one in North Carolina.

Seat belt enforcement programs, however, may not be a priority for many law enforcement

organizations that are responsible for traffic safety. An active seat belt enforcement program combined

with a primary seat belt law has more potential for reducing highway deaths and injuries than most other

traffic enforcement programs.

One of the key factors in the success of the North Carolina program is the strong support from

Governor Jim Hunt and other elected officials. The Safety Board believes that the Governor of the States

and Territories and the Mayor of the District of Columbia should encourage and support efforts by

enforcement organizations to conduct dedicated and highly visible occupant restraint enforcement

programs that focus on increasing the use of seat belts and child restraints. The Board has asked the U.S.

Conference of Mayors, the National League of Cities, the National Association of Counties, and the

National Association of Towns and Townships to take the same action.
70

ACRONYMS AND ABBREVIATIONS

AASHTO American Association of State Highway and Transportation

Officials

ACN Automated Collision Notification

ADT average daily traffic

ATA American Trucking Associations

Caltrans California Department of Transportation

CDL commercial driver’s license

CF Consolidated Freightways, Inc.

CFR Code of Federal Regulations

CTH K County Trunk Highway K

DOT U.S. Department of Transportation

ECM electronic control module

EMS Emergency Medical Service

FARS Fatality Analysis Reporting System

FHWA Federal Highway Administration

GVWR gross vehicle weight rating

HMM Highway Maintenance Manual

LMIS Lockheed-Martin Information Systems

MTI McFaul Transport, Inc.

MUL mandatory use law

NAGHSR National Association of Governors’ Highway Safety

Representatives

NCHRP National Cooperative Highway Research Program

NHS National Highway System

NHTSA National Highway Traffic Safety Administration

OMC Office of Motor Carriers

RWIS road weather information system

SFD Slinger Fire Department

SHRP Strategic Highway Research Program

UPS United Parcel Service

US 41 U.S. Route 41

WCSD Washington County Sheriff’s Department

WisDOT Wisconsin Department of Transportation