NTSB/HAR-02/01

PB2002-916201

National 

Transportation 

Safety Board

Washington, D.C.

A

A

N TION

L TRA SPOR

ATIO

N

B OARD

SAF E T Y

N

T

E PLURIBUS UNUM 

Washington, D.C.

Work Zone Collision Between 

a Tractor-Semitrailer and 

a Tennessee Highway Patrol Vehicle 

Jackson, Tennessee, July 26, 2000

Highway Accident Report 

Highway Accident Report

Work Zone Collision Between 

a Tractor-Semitrailer and 

a Tennessee Highway Patrol Vehicle 

Jackson, Tennessee, July 26, 2000

NTSB/HAR-02/01

PB2002-916201 National Transportation Safety Board

Notation 7465 490 LíEnfant Plaza, S.W.

Adopted May 14, 2002 Washington, D.C. 20594
National Transportation Safety Board. 2002. Work Zone Collision Between a Tractor-Semitrailer and

a Tennessee Highway Patrol Vehicle, Jackson, Tennessee, July 26, 2000. Highway Accident Report

NTSB/HAR-02/01. Washington, DC.

Abstract: About 8:52 a.m. on July 26, 2000, an eastbound 1999 International truck tractor pulling a loaded

semitrailer, and traveling at a driver-estimated speed of 65 mph in a 55-mph work zone, collided with a

Tennessee Highway Patrol (THP) vehicle trailing construction vehicles. Witnesses reported that the patrol

car exploded and caught fire at impact. The patrol car was pushed approximately 192 feet before it came to

rest in the median. The tractor-semitrailer continued through a 61-foot depressed earthen median and into

the westbound lanes, where it collided with a 1997 Chevrolet Blazer. The tractor-semitrailer then

continued across the travel lanes and came to rest in a wooded area on the north side of I-40. The State

trooper in the THP vehicle was killed, and the Chevrolet driver was seriously injured.

The following major safety issues were identified in this accident: 

ï Lack of communication between the Tennessee Department of Transportation, its contractors,

and the Tennessee Highway Patrol.

ï Inadequate planning and coordinating of traffic control responsibilities between highway

construction personnel and law enforcement officers before engaging in work zone activities.

ï Need to train officers in safe traffic control procedures within highway work zones.

As a result of this accident investigation, the Safety Board makes recommendations to the Federal

Highway Administration, the National Highway Traffic Safety Administration, the Tennessee Department

of Transportation, the National Sheriffsí Association, the International Association of Chiefs of Police, and

the American Association of State Highway and Transportation Officials.

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 also

may be obtained from the Web site or by contacting:

National Transportation Safety Board

Public Inquiries Section, RE-51

490 LíEnfant Plaza, S.W.

Washington, D.C. 20594

(800) 877-6799 or (202) 314-6551

Safety Board publications may be purchased, by individual copy or by subscription, from the National Technical Information Service. To

purchase this publication, order report number PB2002-916201 from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(800) 553-6847 or (703) 605-6000

The Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence or use of Board reports

related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report. 
iii Highway Accident Report

Contents

Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Factual Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Accident Narrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Preaccident Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Construction Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Driver Medical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

TDOT Construction Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Preconstruction Conference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Contract Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Work Zone Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Work Zone Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Project CAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

THP Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Postaccident Training Initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Training Programs in Other States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

FHWA Report on Police Use in Work Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

FHWA Rulemaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Work Zone Accident Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

The Accident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Medical Certification Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Driver Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Past Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Communication, Planning, and Coordination Between TDOT and the THP . . . . . . . . . . . 22

Training Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Role of Law Enforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Past Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Work Zone Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Configuration Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Use of TMAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Work Zone Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Probable Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Appendixes

A: Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

B: Jackson, Tennessee, Driver Medical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
iv Highway Accident Report

Acronyms and Abbreviations

AAMVA American Association of Motor Vehicle Administrators

AASHTO American Association of State Highway and Transportation 

Officials

ANPRM advance notice of proposed rulemaking

FARS Fatality Analysis Reporting System

FHWA Federal Highway Administration

FMCSA Federal Motor Carrier Safety Administration

I-40 Interstate Highway 40

MMUCC Model Minimum Uniform Crash Criteria

MUTCD Manual on Uniform Traffic Control Devices

NHTSA National Highway Traffic Safety Administration

NIOSH National Institute for Occupational Safety and Health

OCPS Office of Capital Project Safety

Project CAR Construction Accident Reduction Project

TDOT Tennessee Department of Transportation

THP Tennessee Highway Patrol

TMA truck-mounted attenuator
v Highway Accident Report

Executive Summary

About 8 a.m. on July 26, 2000, a work zone project began near milepost 85.6 on

eastbound Interstate Highway 40 (I-40) in Jackson, Tennessee. This was the third day of

an operation that consisted of milling rumble strips into the shoulder pavement. The three

construction vehicles that were involved were positioned along the outside shoulder of the

interstate. Two Tennessee Highway Patrol vehicles, with their emergency lights flashing,

were also present to assist with enforcement and traffic control. The THP vehicles were

stopped 450 feet and 950 feet, respectively, behind the construction vehicles along the

right lane.

About 8:52 a.m., an eastbound 1999 International truck tractor pulling a loaded

semitrailer, and traveling at a driver-estimated speed of 65 mph in a 55-mph work zone,

collided with the trailing Tennessee Highway Patrol vehicle. Witnesses reported that the

patrol car exploded and caught fire at impact. The patrol car was pushed approximately

192 feet before it came to rest in the median. The tractor-semitrailer continued through a

61-foot depressed earthen median and into the westbound lanes, where it collided with a

1997 Chevrolet Blazer. The tractor-semitrailer then continued across the travel lanes and

came to rest in a wooded area on the north side of I-40. The State trooper in the Tennessee

Highway Patrol vehicle was killed, and the Chevrolet driver was seriously injured.

The National Transportation Safety Board determines that the probable cause of

this accident was the driverís incapacitation, owing to the failure of the medical

certification process to detect and remove a medically unfit driver from service.

Contributing to this accident were the lack of planning and coordination between the

Tennessee Department of Transportation, its contractors, and the Tennessee Highway

Patrol regarding work zone projects; the lack of traffic control training, specific to

highway work zone operations, provided to Tennessee Highway Patrol officers; and the

failure of the Tennessee Department of Transportation and its contractors to protect all

work zone personnel and road users.

The following safety issues were identified in this accident:

ï Lack of communication between the Tennessee Department of Transportation,

its contractors, and the Tennessee Highway Patrol.

ï Inadequate planning and coordinating of traffic control responsibilities

between highway construction personnel and law enforcement officers before

engaging in work zone activities.

ï Need to train officers in safe traffic control procedures within highway work

zones.
vi Highway Accident Report

As a result of this accident investigation, the Safety Board makes recommendations to the Federal Highway Administration, the National Highway Traffic Safety

Administration, the Tennessee Department of Transportation, the National Sheriffsí Association, the International Association of Chiefs of Police, and the American Association of

State Highway and Transportation Officials.

Executive Summary
1 Highway Accident Report

Factual Information

Accident Narrative

About 8 a.m. on July 26, 2000, a work zone project began near milepost 85.6 on

eastbound Interstate Highway 40 (I-40) in Jackson, Tennessee. This was the third day of

an operation that consisted of milling rumble strips1 into the shoulder pavement. The three

construction vehicles that were involved were positioned along the outside shoulder of the

interstate. Two Tennessee Highway Patrol (THP) vehicles, with their emergency lights

flashing, were also present to assist with traffic control. The THP vehicles were stopped

450 feet and 950 feet, respectively, behind the construction vehicles along the right lane.

About 8:52 a.m., an eastbound 1999 International truck tractor pulling a loaded

semitrailer and traveling at a driver-estimated speed of 65 mph in a 55-mph work zone,

collided with the trailing THP vehicle. Witnesses reported that the patrol car exploded and

caught fire at impact. The patrol car was pushed approximately 192 feet before it came to

rest in the median. The tractor-semitrailer continued through a 61-foot depressed earthen

median and into the westbound lanes, where it collided with a 1997 Chevrolet Blazer. The

tractor-semitrailer then continued across the travel lanes and came to rest in a wooded area

on the north side of I-40. (See figures 1 through 4.) The State trooper in the THP vehicle

was killed, and the Chevrolet driver received serious injuries.2

 The officer in the lead THP

vehicle tried to extinguish the flames from the burning THP vehicle with a fire

extinguisher but was unable to do so. A witness reported an attempt was made extricate

the officer from the burning vehicle, but that the heat from the fire was too intense.

At the time of the accident, the weather was clear and the temperature was 78

degrees.

1 Rumble strips or ìaudible roadway delineatorsî are incorporated into shoulders to help prevent driftoff-the-road accidents. Rumble strips may be created by either rolling indentations into the pavement surface

or by milling (grinding) depressions into the pavement.

2 The Chevrolet driverís serious injuries included a fractured arm and multiple lacerations, abrasions,

and contusions. She was belted, and the vehicle air bags deployed, during the accident.
Figure 1. Accident diagram.

Combination vehicle

at res

THP vehicle

at rest

Che

Westbound traffic lanes at rCenter medianEastbound traffic lanes
Factual Information 3 Highway Accident Report

Figure 1. Accident scene.

Figure 2. Wreckage of patrol car.

Figure 2.

Figure 3.
Factual Information 4 Highway Accident Report

Preaccident Events

Driver

According to the driverís logs and to statements made to the THP after the

accident,3 the driver departed Long Beach, California, with a load of computer supplies on

July 20, 2000. He reached Moriarty, New Mexico, on July 23 and rested in the tractorsemitrailerís sleeper berth from 10:00 p.m. to 7:00 a.m. On July 24, he drove for 9 hours

and 30 minutes, performing an additional 45 minutes of on-duty activities upon arriving in

Oklahoma City, Oklahoma. He entered the tractor-semitrailerís sleeper berth at 10:00 p.m.

On July 25, he logged in as ìon dutyî at 7:00 a.m. He drove 9 hours and 15 minutes,

performing an additional 30 minutes of on-duty activities upon arriving in West Memphis,

Arkansas. He entered the sleeper berth at 11:00 p.m. The driver stated to the THP that he

had ìa pretty good nightís sleepî that night. His last log entry indicated that he returned to

duty on July 26, the day of the accident, at 7:00 a.m.

The driver told the THP that this was the second time he had driven through the

construction area near Jackson, Tennessee, in the last 2 months and that he recalled seeing

Figure 3. Wreckage of trailer and Chevrolet Blazer.

3 The driver declined to speak to Safety Board investigators.

Figure 4.
Factual Information 5 Highway Accident Report

signs about the construction before reaching Jackson. He also recalled that the eastbound

traffic was moderate and that the westbound traffic was heavier. The driver did not

remember seeing the patrol car or its flashing blue light until immediately before hitting it.

He stated that he may have tried to swerve, but he did not remember whether he had time

to apply the brakes.

Witnesses driving behind the tractor-semitrailer before the accident stated that they

observed the tractor-semitrailer drifting to the right of the roadway. One witness stated

that he had observed the accident driver drift off the road twice. Another witness stated

that the accident driver drifted off the road several times within a 5-mile span, and that, on

one occasion, the driver ran completely off the road. This witness said he tried to contact

the accident driver on his citizen band radio but could not reach him. He stated that before

the collision, the accident driver had hit his brakes and veered to the left, as if someone

had stopped in front of his vehicle.

Construction Project

The milling of rumble strips on the south shoulder of eastbound I-40 began on July

25th and was scheduled to be completed the next day. The construction vehicles involved

were a milling machine, a sweeper with flashing yellow lights, and a protection vehicle

with flashing yellow lights and a towed arrow board (see figure 5).4

 

4 The arrow display was a panel type C, which is defined in the Manual on Uniform Traffic Control

Devices as having a minimum panel dimension of 96 by 48 inches, a minimum legibility distance of 1 mile,

and a minimum of 15 lighting elements. Such displays are intended for use on high-speed, high-volume

traffic control projects.
Figure 1. General configuration of THP vehicles and milling operations work caravan based on THP statement

accident scene.

Eastbound lanes of Interstate 40

THP vehicles blocking

right traffic lane

(emergency lights are operational)

Construction vehicles

involved in the milling

operation

500' 450'

Figure 5.
Factual Information 7 Highway Accident Report

Under the terms of the construction contract, Dement Construction Company was

responsible for maintaining traffic control during the milling operation. Dement used two

variable message signs, truck-mounted flashing yellow lights, a single portable arrow

direction board, and two marked THP vehicles to accomplish traffic control. The two variable message signs had been placed east of the project in the center medianóone at milepost 82 and the other near exit 85. (See figure 6.) The signs had been configured to

alternate between three messages: 1) USE CAUTION, 2) ONE LANE TRAFFIC AHEAD,

and 3) WORKERS IN ROAD AHEAD. The variable message signs did not specify which

traffic lane was closed.

The THP assigned two officers to the work zone site to provide enforcement and

traffic control support in accordance with the Construction Accident Reduction Project

(Project CAR).5

 Each officer drove a marked patrol vehicle with flashing lights to assist

with traffic control duties. Both vehicles were positioned in the right traffic lane behind

the milling operation. The first vehicle attempted to maintain a distance of about 500 feet

from the rear of the operation, while the second vehicle attempted to maintain a separation

of about 500 feet from the first marked patrol vehicle, or about 1,000 feet from the rear of

the operation.

All of the construction vehicles were positioned on the roadway shoulder.

According to the construction foreman, the only construction vehicle that encroached into

Figure 4. Map of work zone and accident location.

5 The Tennessee Department of Transportation and the THP created Project CAR in 1998 to increase

motorist compliance with work zone traffic control devices. For further information, see the Work Zone

Safety section later in this report.

Figure 6.
Factual Information 8 Highway Accident Report

the traffic lanes of the interstate was the milling machine, which extended approximately 1

to 1.5 feet into the traffic lane and left 10.5 to 11 feet of the lane available for the passage

of traffic. He stated that he believed that the amount of construction vehicle encroachment

into the traffic lane did not warrant a lane closure and that the operation complied with the

guidance provided by the Manual on Uniform Traffic Control Devices (MUTCD).6 The

foreman also stated that he believed the THP presence in the traffic lane was unsafe but

assumed that the officers were familiar with traffic control operations and did not need his

advice. According to the THP, the sweeper that trailed the milling machine also

encroached into the traffic lane by 2 to 3 feet and generated a considerable amount of dust

as it performed its operation.

The Tennessee Department of Transportation (TDOT) Regional Safety

Coordinator stated that he received complaints throughout the day of July 25th that the

messages displayed on the two variable message signs were confusing because motorists

did not know which traffic lane was closed ahead.7

 Additionally, TDOT personnel had

also complained on the previous day to the Regional Safety Coordinator regarding the

unprotected THP vehicles being positioned within the traffic lane. Based on the

complaints he had received, the TDOT Regional Safety Coordinator stated that he planned

to inspect the operation on the following day. The accident occurred before he reached the

work zone.

During a postaccident interview, the construction foreman told Safety Board

investigators that when the milling operation began, he had advised the THP officers who

were assisting with traffic control that the operation would involve a ìmobile lane

closure.î By his definition, a mobile lane closure meant that all of the construction

vehicles would be positioned on the shoulder of the highway and that traffic control efforts

would be directed toward informing motorists ahead of time of the operation and keeping

them away from the shoulder and a safe distance from the milling operation. He stated that

despite the minor encroachment of the construction vehicles into the right traffic lane, he

intended to keep both eastbound traffic lanes open. When the foreman observed the THP

vehicles in the roadway blocking the right traffic lane, he said it made him extremely

nervous. However, he stated that he felt too intimidated to advise the officers that it was

not his intent to have the traffic lane blocked, and he also believed that the officers knew

what they were doing.

The construction foreman further stated that he believed an additional arrow board,

used in conjunction with the existing one, would have enhanced the safety of the

operation. He had intended to include the additional arrow board on the morning of the

accident, but at the time of the accident had not yet incorporated it. The construction diary

for the day before the accident indicated that it was a State work zone inspector who had

suggested incorporating a second arrow board.

6 Federal Highway Administration, Part VI of Standards and Guides for Traffic Controls for Street and

Highway Construction, Maintenance, Utility, and Incident Management Operations. Manual on Uniform

Traffic Control Devices, 1988 edition, revision 3 (Washington, DC: FHWA, 1993).

7 The number of complaints was not tabulated.
Factual Information 9 Highway Accident Report

According to Part VI of the MUTCD,8 routine inspection of traffic control

elements should be performed to ensure acceptable levels of operation. Individuals trained

in the principles of safe traffic control should be assigned responsibility for the safety of

the work sites to ensure that the traffic control measures in use are necessary, that they

conform to the traffic control plan, and that they provide safe conditions to motorists,

pedestrians, and workers alike.

The THP sergeant responsible for scheduling Project CAR officers informed

investigators that when the construction foreman told him that he wanted a mobile lane

closure, the sergeant and his officers understood this to mean that the lane next to the

shoulder was to be closed off. To accomplish this closure, they positioned their marked

THP vehicles within the lane and proceeded to pace the work operation, maintaining a

distance of about 500 feet behind the last vehicle, which was the truck towing the arrow

board.

Driver Medical Information

The investigation revealed that the 50-year-old tractor-semitrailer driver was

involved in a similar accident in July 1997, when he struck a stopped highway patrol car in

Utah, seriously injuring two troopers. The patrol car had been parked on the roadway to

prevent other vehicles from running into a load of spilled gravel.9 After the Jackson,

Tennessee, accident, the driver stated to the THP that he might have fallen asleep

immediately before the accident.

The tractor-semitrailer driverís medical records from a Denver Veteranís

Administration hospital indicated that in December 1996, during in-patient treatment for a

severe infection of his legs, he was evaluated as possibly having obstructive sleep apnea.

His physician recommended that he take part in a formal sleep study; the driver stated that

he needed to return to work and would follow up promptly when he returned to Boise,

Idaho. He did not formally undergo a sleep study until August 1997, the month following

his involvement in the motor vehicle accident that seriously injured two troopers. He was

diagnosed with obstructive sleep apnea and given a device10 to treat his condition. He was

not able to tolerate the device and, in September 1997, underwent surgery to try to correct

the disorder. His hospital records indicated that he suffered complications11 from the

surgery. He failed to keep a postsurgery appointment in the pulmonary clinic and never

scheduled a followup sleep study. The driver did not indicate that he had been diagnosed

or treated for obstructive sleep apnea on any of his commercial driver medical

examination forms.

8 MUTCD, Part VI, 1988 edition, revision 3 (1993).

9 The driver was charged with a misdemeanor and fined.

10 A continuous positive air pressure mask that holds the airway open and keeps oxygen flowing freely

during sleep.

11 Postoperative swelling of the neck, resulting in difficulty swallowing and anxiety.
Factual Information 10 Highway Accident Report

In September 1998, the driver was diagnosed with hypothyroidism12 and placed on

replacement thyroid hormone. He noted this condition on his October 1998 commercial

driver medical examination form and was found by the physician performing the

examination to have markedly diminished deep tendon reflexes.13 The physician noted

that the driver had just begun replacement therapy but did not limit or deny the medical

certificate.

On his August 1999 commercial driver medical examination form, the driver made

no mention of hypothyroidism or his history of sleep apnea. Although he had been

prescribed medication for his hypothyroidism, he indicated that he was not on any

medication.

Following the accident, a pill bottle was found in the driverís truck cab. The bottle

contained 85 of 90 pills of levothyroxine, a thyroid hormone replacement. The

prescription date was 1998, with an expiration date of December 1999. The labeling noted

that the prescription was the first of four available for refill of the medication. A blood test

performed by the THP following this accident indicated that his thyroid hormone level

was markedly low. Symptoms of untreated hypothyroidism may include fatigue, lethargy,

constipation, cold intolerance, stiffness and cramping of the muscles, carpal tunnel

syndrome, and, over time, a slowing of intellectual and motor activity, a decrease in

appetite, and an increase in weight. Obstructive sleep apnea is also associated with

untreated hypothyroidism.14

Neither obstructive sleep apnea nor hypothyroidism is specifically disqualifying

for commercial drivers, although nonbinding Federal Motor Carrier Safety Administration

(FMCSA) advisory criteria note that ìthere are many conditions that interfere with oxygen

exchange Ö including Ö sleep apnea. If the medical examiner detects a respiratory

dysfunction that in any way is likely to interfere with the driverís ability to safely control

and drive a commercial motor vehicle, the driver must be referred to a specialist for

further evaluation or therapy.î15 No FMCSA guidelines address hypothyroidism.

TDOT Construction Project

The work zone project underway at the accident site was part of a TDOT

rehabilitation construction project along a portion of I-40 traversing the city limits of

Jackson, Tennessee. This section of I-40 consists of a four-lane divided highway, with the

eastbound and westbound lanes separated by a 61-foot depressed grassy median. Heavy

vehicles (over 10,000 pounds) constitute approximately 37 percent of the vehicle traffic.

12 A condition of decreased activity of the thyroid gland.

13 Diminished cognitive and motor functions are typical symptoms of hypothyroidism.

14 Leonard Wartofsky, ìDiseases of the Thyroid,î eds. Kurt J. Isselbacher, Eugene Braunwald, and

Jean D. Wilson, et. al., Harrisonís Principles of Internal Medicine, 13th edition (New York: McGraw Hill,

Inc., 1994) 1931-1953.

15 For further information, see <http://www.fmcsa.dot.gov/rulesregs/fmcsr/medical.htm>.
Factual Information 11 Highway Accident Report

When no construction is being performed on this section of I-40, 85 percent of the

vehicles travel at speeds of up to 76 mph. The project, which began on May 11, 2000, was

located within Madison County, encompassing the section of I-40 beginning at Lower

Brownsville Road and continuing east to State Highway 70.16 The project comprised three

phases: pavement resurfacing and the installation of snowplowable reflective markers and

guardrails (phase I), the milling of rumble strips (phase II), and the placement of lane

markings (phase III).

Preconstruction Conference

On February 14, 2000, TDOT held a preconstruction conference. Personnel from

TDOT, Dement Construction,17 and Traf-Mark18 attended the meeting. The attendeesí list

did not show that any THP personnel had attended the conference. In a postaccident

interview, a TDOT representative19 explained to investigators that TDOT had not invited

the THP to its preconstruction meetings because it assumed that the THP did not have the

manpower to participate, given the extensive amount of roadway construction being

performed within the State.

Contract Provisions

The TDOT construction contract included the following traffic control plans:

ï Advance Road Work Signing on Divided Highways and Freeways

ï Traffic Control for One Lane Closure on Multi-Lane Divided Highway (No

Portable Barrier Rail Setup)

ï Traffic Control for Two Right (or Two Left Inside) Outside Lane Closure on

Freeway or Expressway

ï Traffic Control for Two Right Outside (or Two Left Inside) Lane Closure on

Freeway or Expressway (With Interconnected Portable Barrier Rail)

Although the contract contained traffic control plans for lane closure operations, it

did not contain traffic control plans applicable to mobile operations or to shoulder work

with minor encroachment, such as milling rumble strips, pavement striping, and other lane

marking operations. The contract did not specify THP duties with regard to traffic control

within the work zone.

16 Project number 57201-8111-44 comprised 6.13 miles of I-40; project number 57201-8110-44, 6.26

miles.

17 The primary contractor.

18 Subcontractor responsible for placing lane markers and performing pavement scoring operations

within the construction project.

19 Regional Safety Coordinator, Tennessee Department of Transportation, Region 4, telephone

conversation, February 2002.
Factual Information 12 Highway Accident Report

Work Zone Standards

Tennessee used the MUTCD as its standard when creating traffic control plans. At

the time of the accident, the 1988 MUTCD was the most recent edition.20 It was

supplemented by a 1993 revision to one of its chapters (Part VI),21 which provided

additional traffic control guidelines for different types of construction projects. Two such

guidelines pertained to the operational circumstances at the time of the accident: (1)

shoulder work with minor encroachment22 and (2) lane closure on a divided highway.23

The milling operation in Jackson, Tennessee, required at least one construction

vehicle to encroach upon the 12-foot-wide right lane. Under circumstances such as this,

Part VI of the MUTCD allows the encroached lane to stay open as long as there is at least

10 feet of travel space. A traffic sign reading ìroad work aheadî should be placed in

advance of the construction, and additional signs, with a message such as ìroad narrows,î

may also be appropriate. Channelizing devices, such as traffic cones, are optional if the

protection vehicle24 used is equipped with an activated flashing yellow light. Truckmounted attenuators (TMAs), which are compact crash cushions attached to the rear of

protection vehicles, are also optional. Part VI states that for high-speed traffic conditions,

a lane closure should be considered.

The variable message signs in advance of the milling operation alternated between

three messages: (1) USE CAUTION, (2) ONE LANE TRAFFIC AHEAD, and (3) WORKERS IN ROAD AHEAD. In the case of a lane closure on a divided highway, Part VI states

that the work zone should include advance road signs that indicate which lane is closed,

accompanied by a corresponding lane reduction symbol sign. Furthermore, channelizing

devices and a protection vehicle with an activated flashing yellow light should be used to

separate the work zone from the through traffic. TMAs are not required, but recommended.

The purpose of TMAs is to reduce the acceleration forces experienced by

occupants of striking and struck vehicles. They are designed to decelerate and stop

vehicles weighing as much as 4,400 pounds during head-on impacts up to a differential

velocity of 62 mph.25 The American Association of State Highway and Transportation

Officials (AASHTO) Roadside Design Guide provides standards on the proper use of

20 A newer version of the MUTCD (Millennium Edition) was published in December 2000. States have

until January 17, 2003, to reach substantial conformance with the Millennium Edition of the MUTCD.

21 MUTCD, Part VI, 1988 edition, revision 3 (1993).

22 MUTCD, Part VI, 1988 edition, revision 3 (1993) 18-19.

23 MUTCD, Part VI, 1988 edition, revision 3 (1993) 172-173.

24 Protection vehicles include shadow vehicles, barrier vehicles, and advance warning trucks weighing

at least 18,000 pounds.

25 See Recommended Procedures for the Safety Performance Evaluation of Highway Features for more

detailed information on attenuator testing requirements. Transportation Research Board, National Research

Council, Recommended Procedures for the Safety Performance Evaluation of Highway Features, National

Cooperative Highway Research Program Report 350, research sponsored by the American Association of

State Highway and Transportation Officials in cooperation with the Federal Highway Administration

(Washington, DC: National Academy Press, 1993).
Factual Information 13 Highway Accident Report

TMAs. The Roadside Design Guide ìvery highlyî recommends that TMAs be used in

mobile lane operations having no formal lane closure. It also ìhighlyî recommends that

TMAs be used in mobile shoulder operations and in formal lane closures that involve

exposed personnel working in high-speed environments.

In 2001, the National Institute for Occupational Safety and Health (NIOSH) issued

a report on work zone safety that discussed the use of TMAs.26 It recommends that when

worker exposure cannot completely be eliminated, positive protective barriers, such as

TMAs, should be used to shield workers from traffic vehicles. The report adds that TMAs

may be particularly useful in mobile work zones, where they can move forward as work

progresses to protect workers from being struck from behind by traffic vehicles.

TMAs are not designed to stop heavy vehicles, such as trucks and motorcoaches,

although anecdotal evidence exists that, in a few instances, TMAs have reduced the

severity of injuries suffered by construction workers and heavy truck occupants.27,28

Typical TMAs are approximately 12 feet long and are mounted on the back of protection

vehicles. To effectively stop a heavy truck without injuring the occupants of either vehicle,

a TMA would have to be roughly twice as long, leading to weight and transport issues.29

No federally funded research is currently underway on developing TMAs that would

decelerate and stop heavy commercial vehicles.

Work Zone Safety

In late 1997, the Federal Highway Administration (FHWA), in conjunction with

TDOT and the THP, began an assessment project to promote motorist compliance with

traffic control devices and speed limits in and around work zones. Issues identified during

this project included the utilization of police for traffic control and enforcement within

work zones and the ability of law enforcement agencies to gather and report accurate work

zone accident data.

Project CAR

Between 1995 and 1996, 5,140 vehicles were involved in accidents in Tennessee

work zones. With extensive roadway renovations underway near Nashville, Chattanooga,

Memphis, and Knoxville, construction worker fatalities increased 52 percent, from 19 to

29, during that period. In response to the hazardous conditions being experienced at these

and other sites throughout the State, and in order to increase motorist compliance with

26 National Institute for Occupational Safety and Health, Building Safer Highway Work Zones:

Measures to Prevent Worker Injuries From Vehicles and Equipment, DHHS/NIOSH Publication

No. 2001-128 (Washington, DC: DHHS/NIOSH, 2001).

27 National Transportation Safety Board, Highway Work Zone Safety, Safety Study NTSB/SS-92/02

(Washington, DC: NTSB, 1992).

28 Project Engineer, Exodyne Technologies, Incorporated, telephone conversation, February 2002.

29 Safety and Structural Systems Associate Research Engineer, Texas Transportation Institute,

telephone conversation, February 2002, and e-mail correspondence, March 2002.
Factual Information 14 Highway Accident Report

work zone traffic control devices, TDOT and the THP formed a partnership in 1998

known as Project CAR. This initiative provides funds for TDOT to contract with the THP

to station State troopers at work zones experiencing hazardous driving behavior. Project

CARís stated objectives are to:30

ï Reduce work zone fatalities.

ï Encourage State troopers to maintain a goal of two hazardous moving

violations for each hour worked.

ï Ensure that disabled vehicles are expeditiously removed from work zones.

ï Ensure that, upon request, State troopers assist TDOT workers in routing and

directing traffic.

Project CAR does not specify lines of authority or how enforcement and traffic

control are to be conducted. In addition, it does not provide THP officers with training or

guidance on traffic control procedures for work zone operations.

THP Training

The THPís General Order 405 establishes the departmentís policies and

procedures for traffic direction and control. The four pages of guidance contained in the

General Order are presented to THP recruits while attending basic academy training.

General Order 405 provides instruction for departmental procedures, the use of emergency

lighting, and the use of hand signals during the manual direction of traffic. It does not

contain procedures or terminology specific to work zone operations.

Postaccident Training Initiatives

Following this accident, the THP reassessed its training on traffic control

procedures and identified the need to better train its personnel. The THP developed a

1-hour pilot class that was presented to supervisors from January through April 2001. In

addition, from April through August 2001, a 2-hour course was presented to THP officers

as part of their in-service training. The THP plans to incorporate this training into its

academy curriculum by August 2002.31

The FHWA Tennessee Division office in Nashville provided engineering input into

the incident management training that the THP adopted. Building on the THPís program

and working in conjunction with the University of Tennessee Center for Transportation

Research, the FHWA began a project entitled Temporary Traffic Control During Law

Enforcement Incident Management. This project is designed to supplement existing law

enforcement training by incorporating and adapting MUTCD work zone temporary traffic

control elements, safe roadside design practices, and accident reporting procedures. The

initial target group for the training is the THP, but it may be expanded to include other law

30 <http://www.nhtsa.dot.gov/people/outreach/safedige/Fall1999/fall-1499.html>.

31 Office of Planning and Research, Tennessee Highway Patrol, telephone conversation, March 2002.
Factual Information 15 Highway Accident Report

enforcement agencies within the State if successful.32 The FHWA Tennessee Division

office scheduled a pilot training course for May 9, 2002.

Training Programs in Other States

The Safety Board contacted the State police departments of Maryland, Delaware,

Connecticut, and New Jersey to determine whether any of these States train their officers

in work zone safety strategies. Like Tennessee, these States utilize police officers to

increase motorist compliance with work zone traffic laws. Connecticut has a 4-hour-long

work zone training program but does not use it because the State has not recently had a

work zone accident involving a State trooper.33 Delaware34 and Maryland35 do not offer

training specific to work zone safety. In the last three police academy classes, the

Maryland State Police briefly addressed work zone safety as part of a 3-hour incident

management training block.

Since 1994, the New Jersey State Police have specifically trained officers in work

zone safety and traffic control for highway construction areas. Officers in its construction

unit are required to attend a 4-day workshop that teaches MUTCD work zone principles

and procedures. The course also includes Occupational Safety and Health Administration

training about on-the-job risks associated with roadway construction. This training course

is a collaborative effort between the New Jersey State Police, international and local labor

unions, the Utilities and Transportation Contractorsí Association, Rutgers University,

local and county police, and the New Jersey Department of Labor. According to the New

Jersey State Police Web site,36 once training is completed, construction unit officers work

to enforce the rules and regulations governing traffic control and safety in highway work

areas. The officers may inspect construction sites to ensure contractors comply with the

traffic control plans established for their project. The officers may also provide work zone

safety training for local police agencies and for other governmental and private

organizations. New Jersey also provides a 4-hour basic work zone safety course for

officers not assigned to the construction unit.

New Jersey established the construction unit in 1994 to increase the level of

performance of law enforcement personnel in work zones and to provide enforcement

consistency statewide. Among the benefits of the construction unit are more uniform

implementation of approved traffic control plans, better control of the construction

project, and increased safety for workers and the traveling public.37,38 From 1984 to 1993,

New Jersey averaged almost 21 work zone-related fatalities per year.39

32 Safety and Operations Research Team, Federal Highway Administration, Tennessee Division office,

telephone conversation, February 2002.

33 Connecticut State Police, telephone conversation, March 2002.

34 Delaware State Police, telephone conversation, March 2002.

35 Maryland State Police, telephone conversation, March 2002.

36 <http://www.njsp.org/about/traffic.html>.

37 Work Zone Safety Information Clearinghouse, Texas Transportation Institute, in cooperation with the

American Road and Transportation Builders Association <http://wzsafety.tamu.edu>.

38 Supervising Engineer, NJDOT Office of Capitol Project Safety, telephone conversation, March 2002.
Factual Information 16 Highway Accident Report

Since 1994, the State has averaged 12 work zone-related fatalities per year.40

Because work zone data on the frequency, type, length, duration, and location of work

zone projects in New Jersey are not available, it is not possible to determine whether the

reduction in work-zone fatalities can be attributed to the training program.

In addition, New Jersey recently established an Office of Capital Project Safety

(OCPS) to enhance safety in construction work zones and improve the safety awareness of

contractors, construction workers, motorists, and New Jersey Department of

Transportation employees. As problems are identified in work zones, the OCPS plans to

evaluate and resolve the problems and then develop a process to prevent them from

recurring.41

FHWA Report on Police Use in Work Zones

In October 2001, the FHWA published a report summarizing the results of a survey

that it conducted with AASHTO on the use of uniformed police officers for federally

funded highway construction projects.42 Forty-six State transportation agencies responded

to the survey, along with a number of law enforcement agencies and organizations,

highway industry associations, State legislators, and contractors. About two-thirds of the

States responding indicated that they use uniformed police officers in at least some work

zones, most often where particular traffic safety concerns exist, such as in work zones with

high speed and high traffic volume and in work zones with lane closure or nighttime

operations unprotected by a concrete barrier.

Funds to pay for the police presence are generally factored into the overall

construction costs by the State transportation agencies. As with Project CAR in Tennessee,

police funding for work zone projects is generally administered through an interagency

agreement or a memorandum of understanding between the State transportation agency

and the State police.

The FHWA report states that it is not clear from the responses gathered whether

police officers are always familiar with MUTCD procedures. Roughly a quarter of

respondents indicated that their State had a program in place or under development to train

uniformed police officers working in construction projects. One-fifth of the respondents

indicated that officers are trained in traffic operations and traffic management as part of

basic training but are not given specific training on traffic management in work zones. The

responses also suggested that officer supervision arrangements vary; officers are

sometimes supervised by the State department of transportation project engineer,

39 1984 through 1993 data requested from the National Highway Transportation Administration.

40 1994 through 2000 data obtained from the Work Zone Safety Information Clearinghouse Web site

<http://wzsafety.tamu.edu>.

41 Supervising engineer, OCPS, New Jersey Department of Transportation, telephone conversation,

February 2002.

42 Federal Highway Administration, A Study on the Use of Uniformed Police Officers on Federal-Aid

Highway Construction Projects, docket number FHWA-1999-5387 (Washington, DC: FHWA, 2001).
Factual Information 17 Highway Accident Report

sometimes by the contractor, and other times by the law enforcement agency supervisor on

duty.

In response to these findings, the FHWA made the following recommendations to

State agencies that use Federal highway funds to assign uniformed police officers to

highway work zones:

ï Develop guidelines addressing (a) when to use uniformed police officers, (b)

the traffic control planning process, and (c) officer pay, work procedures, and

supervision.

ï Provide training in MUTCD requirements to police officers assigned to

federally funded highway work zones. (Note: Federal regulations require the

use of MUTCD signing and flagging procedures in federally funded highway

work zones.)

ï Gather data on traffic safety incidents occurring in federally funded highway

work zones to better assess the effectiveness of traffic control techniques.

ï Consider using new traffic control technologies, such as automated

enforcement and intrusion alarms.

FHWA Rulemaking

On February 6, 2002, the FHWA released an advance notice of proposed

rulemaking (ANPRM) regarding improvements to its regulations on Traffic Safety in

Highway and Street Work Zones.43 In the ANPRM, the FHWA identified a set of issues

that may be addressed, including general policy and regulatory considerations,

transportation planning and programming, project design for construction and

maintenance, managing for mobility and safety in and around work zones, public outreach

and communications, and analyzing work zone performance. The ANPRM does not

address the need for training for law enforcement officers involved in work zone

operations.

Work Zone Accident Statistics

In the past 5 years, the number of traffic fatalities occurring in work zones has

risen. In 1996, 717 individuals were killed in work zone-related accidents; by 2000, that

number had increased to 1,093. (See figure 7.) The number killed in work zones located in

principal arterials, where travel speeds are normally higher, also increased from 483 in

1996 to 641 in 2000. During that 5-year period, the number of work zone fatalities in

which heavy vehicles were involved increased from 153 to 219.44 Commercial vehicles

account for 7 percent of all vehicle miles driven per year. They are involved in 3 percent of

43 Work Zone Safety, 67 Federal Register (FR) 5532.

44 Data obtained via the Fatality Analysis Reporting System (FARS) Web-based Encyclopedia

<http://www-fars.nhtsa.dot.gov>.
Factual Information 18 Highway Accident Report

all injury accidents, 9 percent of all fatal accidents, and 20 percent of all fatal work zone

accidents.45

The number of work zone projects is increasing due to maintenance required on

the Nationís aging roadway infrastructure.46 Exposure data on the frequency, type, length,

duration, and location of work zone projects are not available, and the extent to which the

rise in fatalities may be due to the increase in driver exposure to work zones is not known. 47

What is known is that vehicle miles traveled have steadily increased,48 as have capital

outlays for highway maintenance projects.49

45 Federal Motor Carrier Safety Administration, Large Truck Crash Overview, 1998 and 1999 editions,

<http://www.fmcsa.dot.gov/factsfigs/formspubs.htm> (Washington, DC: FMCSA, 1998 and 1999).

Figure 5. Annual work zone fatalities (1996-2000).

46 Safety Study NTSB/SS-92/02.

47 Recently published research on a limited dataset of California interstate work zones indicates that

accidents increase significantly on roadways where work zones are present. Additionally, there is a positive

correlation between work zone lengths and accident frequencies. See Asad J. Khattak, Aemal J. Khattak,

and Forrest M. Council, ìEffects of Work Zone Presence on Injury and Non-injury Crashes,î Accident

Analysis and Prevention, Vol. 34 (1) (2002) 19-29.

48 <http://www-fars.nhtsa.dot.gov>.

49 Federal Highway Administration, Highway Statistics 2000, <http://www.fhwa.dot.gov/ohim/hs00/index.htm>

(Washington, DC: FHWA, 2000).

0

200

400

600

800

1000

1200

Figure 7. 1996 1997 1998 1999 2000
19 Highway Accident Report

Analysis

This analysis recounts the events leading to the Jackson, Tennessee, accident,

examines related medical certification issues and then focuses upon the factors that led to

the unsafe conditions for both motorists and workers: (1) the planning and coordination

between TDOT, its contractors, and the THP regarding the work zone operation underway

at the time of the accident and (2) the degree of traffic control training in highway work

zone operations received by THP officers. Finally, the analysis examines whether TMAs

might have ameliorated the severity of this accident.

The Accident

About 8 a.m. on July 26, 2000, two THP officers positioned their vehicles, with

their emergency lights flashing, within the right eastbound lane of a high-speed roadway

in order to warn motorists away from the milling machine and the sweeper on the roadway

shoulder. Although variable message signs warned motorists of the roadwork ahead and of

a lane closure, the signs failed to specify which lane was closed. No channeling devices

were positioned behind the officers to direct motorists to the left lane. In addition, the

protection vehicle towing the flashing arrow board was positioned behind the sweeping

machine, 950 feet ahead of the trailing police vehicle.

Less than an hour after the work zone project began, a loaded tractor-semitrailer

entered the 55-mph work zone, traveling in the right lane at a driver-estimated speed of 65

mph. The tractor-semitrailer collided with the trailing THP vehicle, causing the smaller

vehicle to explode upon impact and to be dragged approximately 192 feet before coming

to rest in the highway median. The tractor-semitrailer continued through the highway

median into the westbound lanes, collided with a 1997 Chevrolet Blazer, and finally came

to rest in a wooded area on the north side of I-40.

After the accident, a THP officer and a witness attempted to extinguish the flames

from the burning THP vehicle and extricate the officer inside, but were unable to do so

because of the intense heat. The Safety Board concludes that the severity of the tractorsemitrailer’s impact with the trailing police car and the subsequent explosion and fire

made this accident unsurvivable for the officer in the trailing THP vehicle.

The situation that confronted motorists as they entered the work zone was

challenging. On the previous day, vague messages displayed on the variable message signs

had prompted motorists to complain to TDOT that they could not tell which lane was

closed. The unprotected positions of the THP vehicles had generated sufficient complaints

by TDOT personnel to the Regional Safety Director to merit an inspection of the work

zone operation. The accident occurred before this inspection could take place.
Analysis 20 Highway Accident Report

The tractor-semitrailer driver, who had been diagnosed with obstructive sleep

apnea in 1997 and hypothyroidism in 1998, had continued to drive after the diagnoses. A

subsequent investigation revealed that it was unclear whether the driver’s chronic and

potentially incapacitating medical conditions had been treated successfully. Witnesses

reported that before the collision, the driver had drifted off the road at least twice. The

driver himself told the THP that he might have fallen asleep at the time of the accident.

Medical Certification Issues

Driver Factors

The tractor-semitrailer driver’s medical records indicate that in August 1997, he

was formally diagnosed with sleep apnea, 1 month after colliding with a police vehicle

and injuring two officers. Although he underwent surgery for his condition, he failed to

keep postsurgical appointments. He did not schedule a followup sleep study, making it

difficult to assess the success of the surgery.

The driver also suffered from hypothyroidism, but he did not mention this or his

history with obstructive sleep apnea to the examiner during his August 1999 commercial

driver medical examination. Moreover, he had been prescribed medication for his

hypothyroidism, but indicated that he was not on any medication. Following the accident,

a pill bottle nearly full of thyroid hormone medication was found in the truck cab. A

postaccident blood test performed by the THP indicated that his thyroid hormone level

was markedly low. Apparently, the driver took only a few pills of the last prescription

filled in 1998 for thyroid hormone and never followed up on his thyroid condition. The

Safety Board concludes that the driver’s obstructive sleep apnea, his untreated

hypothyroidism, or complications from either or both conditions predisposed him to

impairment or incapacitation, including falling asleep at the wheel, while driving.

Past Recommendations

This accident investigation raises many of the same medical certification issues

that the Safety Board addressed in its report50 on a 1999 motorcoach accident in New

Orleans that killed 22 passengers and injured 22 others. The motorcoach driver involved

was able to renew his commercial driver medical certificate, and thereby retain his

commercial driver’s license, despite suffering from several life-threatening medical

conditions of the kidneys and heart that affected his ability to perform his duties and

required him to undergo 3- to 4-hour-long clinical treatments 6 days a week. The New

Orleans report details several factors that contributed to the failure of the medical

certification process to prevent unfit drivers from operating a commercial vehicle. As a

result of its investigation, the Safety Board made recommendations to the FMCSA and

50 National Transportation Safety Board, Motorcoach Run-off-the-Road Accident, New Orleans,

Louisiana May 9, 1999, Highway Accident Report NTSB/HAR-01/01 (Washington, DC: NTSB, 2001).
Analysis 21 Highway Accident Report

other organizations to develop a comprehensive medical oversight program for interstate

commercial drivers that contains the following program elements:

H-01-17

Individuals performing medical examinations for drivers are qualified to do so

and are educated about occupational issues for drivers.

H-01-18

A tracking mechanism is established that ensures that every prior application by

an individual for medical certification is recorded and reviewed.

H-01-19

Medical certification regulations are updated periodically to permit trained

examiners to clearly determine whether drivers with common medical conditions

should be issued a medical certificate.

H-01-20

Individuals performing examinations have specific guidance and a readily

identifiable source of information for questions on such examinations.

H-01-21

The review process prevents, or identifies and corrects, the inappropriate issuance

of medical certification.

H-01-22

Enforcement authorities can identify invalid medical certification during safety

inspections and routine stops.

H-01-23

Enforcement authorities can prevent an uncertified driver from driving until an

appropriate medical examination takes place.

H-01-24

Mechanisms for reporting medical conditions to the medical certification and

reviewing authority and for evaluating these conditions between medical

certification exams are in place; individuals, health care providers, and employers

are aware of these mechanisms.

The Safety Board also issued Safety Recommendation H-01-26 to the American

Association of Motor Vehicle Administrators (AAMVA) to urge its member States to

develop a comprehensive medical oversight program for intrastate commercial drivers

that contains the same elements. The FMCSA responded to Safety Recommendations

H-01-17 through –24 in an April 11, 2002, letter; that response was under review at the
Analysis 22 Highway Accident Report

time this report went to publication. The AAMVA has not yet responded to Safety

Recommendation H-01-26.

Considerable effort will be required to create a comprehensive medical oversight

program that is both effective and feasible. However, the Jackson, Tennessee, accident

again demonstrates how easily unfit drivers are able to take advantage of the inadequacies

of the current medical system, resulting in potentially fatal consequences. The Safety

Board therefore concludes that had a comprehensive medical oversight program been in

place at the time of the accident, this driver, who had known and potentially incapacitating

medical conditions, would have been considerably less likely to be operating a

commercial vehicle. The Safety Board urges both the FMCSA and AAMVA to act quickly

to develop a comprehensive medical oversight plan for commercial drivers.

Communication, Planning, and Coordination Between TDOT and 

the THP

Project CAR was a mechanism for TDOT to contract with the THP to provide

enforcement and traffic control assistance on this construction project. Despite the THP’s

role in the project, it was not invited to attend the TDOT preconstruction conference

meetings. Typically, participants in a preconstruction conference discuss the scope of a

construction project; the time, resources, and procedures needed to complete it; and the

traffic control plan that best suits each phase of the project. Large projects, such as the one

in Jackson, Tennessee, usually involve the State’s department of transportation and several

contractors and subcontractors. Because of the number of parties involved,

communication and coordination are vital in establishing a work zone strategy that is both

effective and safe.

Not seeking THP representation resulted in a lost opportunity for Dement

Construction and THP representatives to coordinate traffic control duties. It also meant

that TDOT could not clarify to all involved who was in charge of traffic control in the

work zone. This clarification would have been helpful, given the natural assumption that

police officers are in charge of traffic control. The end result was a disjointed traffic

control effort between the TDOT contractor and the THP that was inherently unsafe. The

Safety Board concludes that had TDOT invited the THP to the preconstruction

conferences, lines of communication may have been established, enabling the parties to

agree upon traffic control responsibilities and clarify the manner in which they should be

performed.

At the time of the accident, TDOT was employing a traffic control strategy that

was not covered in the construction contract. In fact, the contract did not contain a traffic

control plan that was applicable to mobile operations such as milling rumble strips or

performing pavement striping and other lane marking operations. Furthermore, the

contract did not specify the THP’s duties with regard to traffic control within the work

zone.
Analysis 23 Highway Accident Report

The failure to define a specific traffic control plan for the milling operation

suggests that too little planning had been devoted to that operation, which may have led to

the ambiguous information displayed on variable message signs and to other questionable

safety practices discussed below. The lack of a specific traffic control plan, in conjunction

with the absence of the THP in the preconstruction conferences, quite likely added to the

contractor’s uncertainty with regard to the THP’s role in the milling project. These

circumstances may have fostered the misconception that the THP officers did not need

additional guidance on work zone operations. The Safety Board concludes that the traffic

control and safety aspects of the work zone operation would have been improved had the

construction contract incorporated traffic control plans for all aspects of the work zone

operation and assigned specific responsibilities to each party. The Safety Board believes

that the Tennessee Department of Transportation should conduct preconstruction

conferences with all parties involved in a work zone project. Further, as a result of such

conferences, TDOT should produce a written traffic control plan or project plan agreed to

by all parties that defines the lines of authority and how traffic control and enforcement

will be performed for all types of work zone configurations to be utilized.

According to the FHWA’s 2001 study on the Use of Uniformed Police Officers on

Federal-Aid Highway Construction Projects, a majority of the States use uniformed police

officers in at least some work zones, most often where particular traffic safety concerns

exist, such as in work zones with high speed and high traffic volume and in work zones

with lane closure or nighttime operations unprotected by a concrete barrier. Part VI of the

MUTCD encourages the use of police officers in work zone operations, stating that the

“use of police in vulnerable work situations, particularly those of relatively short duration,

heightens the awareness of passing traffic and will likely cause a reduction in travel

speed.”

Although the use of police officers is promoted as a way to increase work zone

safety, no specific guidance exists that addresses the need to coordinate traffic control and

enforcement activities with the officers. The MUTCD, which codifies the principles and

procedures used by all States when designing and implementing work zones, does not

provide guidance on this issue. The accident in Jackson, Tennessee, illustrates the

importance of a coordinated effort in creating a safe work zone environment for workers

and the traveling public. The Safety Board concludes that the widespread use of police

officers at highway work zones underscores the need for standard guidance to assist

construction and maintenance workers in coordinating traffic control, enforcement, and

other safety-related tasks with police officers assigned to work zones. The Safety Board

believes that the Federal Highway Administration should review and revise the Manual on

Uniform Traffic Control Devices to provide guidance on coordination with law

enforcement personnel used in traffic control strategies at highway work zones.
Analysis 24 Highway Accident Report

Training Issues

Role of Law Enforcement

Law enforcement personnel typically perform short-term traffic control functions

for specific events. These functions include providing enforcement and traffic control

support at accident scenes, at intersections with malfunctioning or missing traffic control

devices, in work zones, when escorting permitted (oversize) vehicles, and during special

events that generate heavy traffic. However, THP General Order 405, which governs

traffic direction and control, does not provide guidance for the unique situations found in

long-term work zone environments. For this reason, the THP officers lacked the guidance

and training necessary to provide safe and effective traffic control for work zone

operations.

As part of its investigation, the Safety Board conducted a limited survey of the

police work zone training practices in Maryland, Delaware, Connecticut, and New Jersey.

Among those surveyed, only New Jersey had officers who are trained in Part VI of the

MUTCD and other traffic control safety standards. New Jersey State Police assigned to

the construction unit are authorized to enforce the rules and regulations governing traffic

control and safety in highway work areas. The officers may even inspect construction sites

to ensure that contractors comply with the traffic control plans established for their

projects. According to the supervising engineer of the New Jersey Department of

Transportation Office of Capitol Project Safety, having trained officers patrolling New

Jersey work zones has resulted in more uniform implementation of traffic control plans,

better control of construction projects, and increased safety for workers and the traveling

public.

Instruction and training similar to that given to the New Jersey construction unit

would have benefited the THP officers assigned to the milling operation in Jackson,

Tennessee. Prior to the milling operation, the Dement construction foreman advised the

THP officers that the operation would involve a “mobile lane closure.” By this, he meant

that all of the construction vehicles would be positioned on the shoulder of the highway

and that traffic control efforts would be directed toward informing motorists ahead of time

of the operation and keeping them away from the shoulder and a safe distance from the

milling operation. Although the construction foreman indicated that he did not intend that

the THP close the right lane, the phrase “mobile lane closure” could easily be construed to

mean “close the lane.” “Mobile lane closure” is not a term used in the MUTCD, nor was a

mobile operation mentioned in the Jackson traffic control plan. Yet, the THP did not ask

for clarification and proceeded to position their vehicles behind the construction vehicles

in an unsafe manner. The Safety Board concludes that had the THP officers received work

zone traffic control training, they may have asked the construction foreman for

clarification on the traffic control strategy to be used that day. The Safety Board further

concludes had the THP officers received work zone traffic control training, they would

have realized the hazards of positioning their vehicles in the lane behind the highway

construction vehicles.
Analysis 25 Highway Accident Report

Since the Jackson, Tennessee, accident, the THP has worked with the FHWA to

develop training programs on MUTCD traffic control strategies for its supervisors and

officers. The Safety Board supports the efforts of the THP and the FHWA to reduce work

zone-related accidents through training. This effort places Tennessee in the forefront on

the work zone training issue because, as the FHWA’s survey on the use of uniformed

police officers indicates, three-fourths of responding State agencies do not have a program

in place or under development to train police officers on work zone safety standards. New

Jersey has adopted such a training program and believes that it has contributed to the

implementation of more uniform traffic control plans and better controlled construction

projects and has also led to a significant reduction in work zone-related fatalities.

Therefore, the Safety Board believes that the FHWA, in cooperation and consultation with

the National Highway Traffic Safety Administration (NHTSA), the International

Association of Chiefs of Police, the National Sheriffs’ Association, and AASHTO should

develop a model training program for law enforcement personnel that addresses traffic

control strategies at highway work zones, and encourage the States to adopt it. At a

minimum, the training program should incorporate material from Part VI of the MUTCD

and information concerning procedures and terminology typically used by highway

engineers in establishing and evaluating work zone operations.

Past Recommendations

Other recent accident investigations have raised concerns that law enforcement

officers sometimes lack the training to conduct activities that are not a part of their normal

duties. In December 2001, the Safety Board adopted a report51 that described the events

leading to the collision between a commuter train and a tractor combination vehicle

carrying an oversized/overweight load. As a result of its investigation, the Safety Board

recommended that the International Association of Chiefs of Police and the National

Sheriffs’ Association:

H-01-36

Notify your members of the circumstances of the Glendale, California, accident

and encourage them to train their officers to make sure (1) that documentation

regarding permits is reviewed and verified; (2) that safety briefings to discuss

routings and special conditions, including the hazards associated with moving

oversize/overweight vehicles over grade crossings, are conducted; (3) that

provisions for handling off-route loads are in place; and (4) that necessary

notification to the railroads is made before an oversize/overweight vehicle is

escorted across a highway-railroad grade crossing.

51 National Transportation Safety Board, Collision Between Metrolink Train 901 and Mercury

Transportation, Inc., Tractor-Combination Vehicle at Highway-Railroad Grade Crossing in Glendale,

California, on January 28, 2000, Highway Accident Report NTSB/HAR-01/02 (Washington, DC: NTSB,

2001).
Analysis 26 Highway Accident Report

The report also recommended that the FHWA, in cooperation and consultation

with the FMCSA and trade associations:52

H-01-31

Develop model oversize/overweight vehicle movement guidelines. The guidelines

should address, at a minimum, issues such as (1) when pilot cars and police

escorts are required; (2) the training, testing, and certification of pilot car

operators, police officers, and truck drivers in the movement of

oversize/overweight loads; (3) the use of height poles and traffic controls; (4) how

to conduct route surveys; (5) the maneuvering limitations of heavy-haul vehicles;

(6) the effects of fatigue on performance; (7) the need to assess the dangers at

railroad crossings, particularly for low-clearance vehicles; and (8) the need and

requirements to notify the railroads before an oversize/overweight vehicle is

escorted across a highway-railroad grade crossing.

In addition, the Safety Board issued a companion recommendation (H-01-33)

urging the FMCSA and trade associations to work with the FHWA to accomplish Safety

Recommendation H-01-31. Owing to the relatively short time since these

recommendations were issued, as of April 2002, they are classified “Open—Await

Response.” The Safety Board looks forward to learning about the results of joint

Government, industry, and law enforcement initiatives to ensure the safety of vehicles in

unique traffic situations.

Work Zone Safety

Configuration Criteria

The construction foreman stated to Safety Board investigators that he had advised

the THP officers who were assisting with traffic control that the operation would involve a

mobile lane closure. The construction foreman further stated to Safety Board investigators

that when he advised the THP officers who were assisting with traffic control that the

operation would involve a mobile lane closure, his intent was to keep both traffic lanes

open. The foreman noted that the configuration used in the work zone met MUTCD

requirements.53

Some disagreement exists regarding the extent to which the construction vehicles

encroached upon the roadway. Nonetheless, the presence of the THP vehicles in the right

lane effectively made this a lane closure operation. TDOT contracted with the THP to

assist with traffic enforcement and traffic control during the construction project. As such,

the THP officers were part of the construction crew. The 1993 Part VI revision of the

MUTCD indicates that certain traffic control elements should be present for a lane closure

52 AASHTO, the AAMVA, the Commercial Vehicle Safety Alliance, the Specialized Carriers and

Rigging Association, the California Professional Escort Car Association, the Texas Pilot Car Association,

and the United Safety Car Association.

53 MUTCD, Part VI, 1988 edition, revision 3 (1993).
Analysis 27 Highway Accident Report

on a divided highway, including advance road signs indicating that the appropriate lane is

closed, a corresponding lane reduction symbol sign, a protection vehicle with an activated

flashing yellow light, and channelizing devices to separate the work zone from the through

traffic.

Several of these traffic control elements were missing in the Jackson work zone.

The variable message signs used did not specify which lane ahead was closed, and they

were not accompanied by a corresponding lane reduction symbol sign. Channelizing

devices to separate the work zone from the through traffic were not used. Although a

protection vehicle with a flashing arrow board was present, it was not positioned to warn

vehicles away from the THP vehicles. Therefore, the Safety Board concludes that the

traffic control configuration used by TDOT and its contractors did not meet MUTCD

requirements for a lane closure on a divided highway.

The precautions taken by TDOT, its contractors, and the THP were insufficient to

protect the officers, construction workers, and road users. The most obvious problem was

the unprotected position of the patrol cars on the roadway. Although lines of

communication had not been established for this project, and although the foreman’s

statements suggest that he had some trepidation in advising the officers on traffic control,

these factors do not relieve TDOT or its contractors of their responsibility to clarify their

traffic control intent to the officers, to voice their concerns regarding the officers’ presence

in the travel lane, and to follow the prescribed traffic control plans. These factors also

should not have kept the THP from recognizing that, as members of the construction crew,

they have a responsibility to coordinate activities with TDOT and its contractors.

Had the THP vehicles not been positioned in an active lane during the milling

operation, TDOT and its contractor would not have been required, under the MUTCD, to

close a traffic lane. However, the presence of the THP vehicles in the right lane obligated

TDOT and its contractors to adopt a lane closure strategy to protect the exposed vehicles.

This strategy should have included changing the variable message signs to indicate that

the right lane was closed ahead and accompanying them with corresponding lane

reduction symbol signs. In addition, channelizing devices should have been put in place to

separate the construction and police vehicles from the through traffic, and a protection

vehicle with an arrow board and a TMA should have been positioned to trail the police

vehicles within the channelizing devices. Therefore, the Safety Board concludes that

TDOT, its contractors, and the THP failed to take the precautions necessary to protect all

workers and road users within the work zone.

Use of TMAs

In the Jackson accident, the police vehicles were, in effect, acting as protective

barriers for the construction workers in the milling operation, a practice not sanctioned by

either the MUTCD or the AASHTO Roadside Design Guide. Given the hazardous nature

of this practice, the Safety Board examined whether having a TMA positioned behind the

THP vehicles would have reduced the severity of this accident. As mentioned previously,

TMAs are compact crash cushions attached to the rear of protection vehicles that are

intended to protect construction workers and the occupants of a striking vehicle. They are
Analysis 28 Highway Accident Report

designed to decelerate and stop vehicles as heavy as 4,400 pounds, traveling at speeds of

up to 62 mph. In the Jackson accident, the weight (48,000 pounds)54 and speed (65 mph)

of the striking tractor-semitrailer far exceeded the design parameters of a TMA. Had a

TMA-equipped protection vehicle been positioned behind the police vehicles, it would

quite likely have been destroyed and its driver killed or seriously injured.

The protection offered by TMAs has improved since the Safety Board published

its 1992 safety study55 on highway work zone safety. At that time, TMAs were designed

for an impact speed of up to 45 mph. In the 1992 study, the Safety Board evaluated several

accidents involving both cars and heavy trucks in which TMAs were used and concluded,

“Truck-mounted attenuators used on vehicles in moving maintenance operations and on

barrier vehicles at stationary work zone sites can substantially reduce the severity of

accidents in these work zones.” The Safety Board recommended that the FHWA:

H-92-36

Conduct research, in conjunction with industry, to determine the effectiveness of

truck-mounted attenuators when struck at various angles and offsets and at speeds

in excess of 45 mph, and analyze the safety benefits and shortcomings of using

truck-mounted attenuators in such high-speed environments.

Since receiving this recommendation, the FHWA has published a report defining

the testing parameters for TMAs,56 including crash tests at speeds up to 62 mph. The

report also defines the parameters for 10-degree-offset crash tests, but considers these

types of tests to be optional, noting “there is no assurance that new TMA designs can be

made to meet these test requirements without significant increases in cost or without

detrimental effects on truck handling.” Nonetheless, the report encourages manufacturers

to design with this goal in mind. Consequently, on September 16, 1994, the Safety Board

classified Safety Recommendation H-92-36 “Closed—Acceptable Alternate Action.”

Approximately 80 percent of work zone accidents involve smaller passenger

vehicles, and TMAs are designed to dissipate the energy of impacts involving such

vehicles. In the absence of more definitive data, the recent increase in overall work zone

fatalities suggests that greater use of work zone TMAs may be warranted. The Safety

Board concurs with NIOSH that when worker exposure cannot be eliminated completely,

positive protective barriers, such as TMAs, should be used to shield workers from traffic.

Work Zone Data

During its investigation, the Safety Board attempted to find exposure data57 that

would help clarify the increase in work zone fatalities. Exposure data are necessary

54 The tractor-semitrailer was fully loaded with computers and computer supplies at the time of the

accident. The average weight of such vehicles, when fully loaded, is between 70,000 and 75,000 pounds;

they can weigh as much as 80,000 pounds without having to be permitted.

55 Safety Study NTSB/SS-92/02.

56 Recommended Procedures for the Safety Performance Evaluation of Highway Features, National

Cooperative Highway Research Program Report 350, 1993.
Analysis 29 Highway Accident Report

because risk cannot be fully determined using fatality data alone, since fatality data do not

account for changes in the frequency, duration, and length of work zones, nor do they

account for the location and type of construction being performed. Exposure data might

also have helped the Board determine whether the issues identified in the Jackson,

Tennessee, collision were isolated to this accident or were more far reaching. However,

investigators found that work zone-related exposure data are not gathered nationally.

In its 1992 study on work zone safety,58 the Safety Board concluded that the lack of

exposure data for work zone accidents makes it difficult to compare accident rates in work

zones with accident rates on roads elsewhere. Therefore, the Safety Board issued the

following recommendations to NHTSA and the FHWA:

H-92-33

Review, in conjunction with the Federal Highway Administration, all State

accident report forms, select the data elements that comprehensively document

work zone accidents, and encourage the States to incorporate these data elements

into their accident report forms.

H-92-34

Review, in conjunction with the National Highway Traffic Safety Administration,

all State accident report forms, select the data elements that comprehensively

document work zone accidents, and encourage the States to incorporate these data

elements into their accident report forms.

NHTSA created the Model Minimum Uniform Crash Criteria (MMUCC) in

response to Safety Recommendation H-92-33. The MMUCC is a voluntary set of

guidelines that help States collect consistent, reliable accident data that are more effective

for identifying traffic safety problems, establishing goals and performance measures, and

monitoring the progress of programs. These guidelines include a data element for work

zone accidents, which allows police officers to specify where in a work zone an accident

occurred. Officers can also specify the work zone type and whether construction workers

were present at the time of the accident. NHTSA has encouraged the States to adopt the

MMUCC through training and educational programs in conjunction with the FHWA, the

National Association of Governors’ Highway Safety Representatives, and others.

Consequently, the Safety Board classified this recommendation “Closed—Acceptable

Action” on April 5, 2001.

Although NHTSA does not track the number of States that have adopted all or part

of the MMUCC, it believes that about 40 percent of the States have altered their accident

reports to incorporate MMUCC data elements. NHTSA is currently hosting a State

compatibility working group to address general concerns with the MMUCC and plans to

57 Data with a common characteristic, such as vehicle miles traveled, that enable better comparison of

data from disparate sources.

58 Safety Study NTSB/SS-92/02.
Analysis 30 Highway Accident Report

hold a workshop for State representatives in August 2002. NHTSA expects to publish an

updated version of the MMUCC by 2003.59

In response to Safety Recommendation H-92-34, the FHWA determined that a

standard definition for a work zone had to be developed first. In December 2000, the

FHWA revised the Millennium edition, Section 6C.02, of the MUTCD to include the

following definition:

A work zone is an area of a highway with construction, maintenance, or utility

work activities. A work zone is typically marked by signs, channelizing devices,

barriers, pavement markings, and/or work vehicles. It extends from the first

warning sign or rotating/strobe lights on a vehicle to the END ROAD WORK sign

or the last temporary traffic control device.

This definition provides public safety personnel with a baseline for recording

accidents in and around work zones, and the FHWA has requested that the States include

specific data elements on their accident reporting forms that account for work zones.60 As

a result of these efforts, the Safety Board classified this recommendation “Closed—

Acceptable Action.”

In addition to pointing out the lack of exposure data available on work zone

accidents, the Board’s 1992 study noted deficiencies in its collection. Therefore, the

Safety Board recommended that the FHWA:

H-92-35

Develop a program to collect exposure data for construction work zones on the

interstate system.

The FHWA has two research efforts underway to determine the influence of work

zones on crash rates, the sources of information now available to generate exposure data,

and the availability of other types of exposure data that might further benefit the safety

and performance assessment of work zones. Exposure data are being gathered on a limited

basis for these efforts; those data include the annual percentage of the Nation’s highways

with at least 1 day of work zone activity, the number of vehicles that traverse work zones

annually, the total worker-hour exposure in work zones, traffic density, and work zone

length, type, and duration. Current work zone crash and fatality statistics will also be

assessed with respect to the exposure measures developed for this task. The results from

one of these research efforts are expected in spring 2002 and the other in fall 2002. 

While the MMUCC provides a mechanism for the States to collect more accurate

and detailed information on work zone accidents, little can be learned from the number of

work zone injuries and fatalities without first knowing more about the conditions in which

59 Team Leader, State Data and Quality Assurance Branch, National Center for Statistics and Analysis,

NHTSA, telephone conversation, April 16, 2002.

60 Transportation Specialist, Safety Core Business Unit, Federal Highway Administration, e-mail

correspondence, April 2002.
Analysis 31 Highway Accident Report

they occurred. An accounting of work zone characteristics, including types, frequency,

duration, length, and location of operations, is needed to permit researchers to determine

accident rates under differing conditions, thereby allowing for better assessments of safety

procedures and equipment. Therefore, the Safety Board expects that the FHWA report will

allow the agency to quickly act upon the Board’s decade-old recommendation to collect

work zone exposure data. In the meantime, this recommendation remains “Open—

Acceptable Response.” 
32 Highway Accident Report

Conclusions

Findings

1. The severity of the tractor-semitrailerís impact with the trailing police car and the

subsequent explosion and fire made this accident unsurvivable for the officer in the

trailing Tennessee Highway Patrol vehicle.

2. The driverís obstructive sleep apnea, his untreated hypothyroidism, or complications

from either or both conditions predisposed him to impairment or incapacitation,

including falling asleep at the wheel, while driving.

3. Had a comprehensive medical oversight program been in place at the time of the

accident, this driver, who had known and potentially incapacitating medical

conditions, would have been considerably less likely to be operating a commercial

vehicle.

4. Had the Tennessee Department of Transportation invited the Tennessee Highway

Patrol to the preconstruction conferences, lines of communication may have been

established, enabling the parties to agree upon traffic control responsibilities and

clarify the manner in which they should be performed.

5. The traffic control and safety aspects of the work zone operation would have been

improved had the construction contract incorporated traffic control plans for all

aspects of the work zone operation and assigned specific responsibilities to each

party.

6. The widespread use of police officers at highway work zones underscores the need

for standard guidance to assist construction and maintenance workers in coordinating

traffic control, enforcement, and other safety-related tasks with police officers

assigned to work zones.

7. Had the Tennessee Highway Patrol officers received work zone traffic control

training, they may have asked the construction foreman for clarification on the traffic

control strategy to be used that day.

8. Had the Tennessee Highway Patrol officers received work zone traffic control

training, they would have realized the hazards of positioning their vehicles in the lane

behind the highway construction vehicles.

9. The traffic control configuration used by the Tennessee Department of Transportation

and its contractors did not meet Manual on Uniform Traffic Control Devices

requirements for a lane closure on a divided highway.
Conclusions 33 Highway Accident Report

10. The Tennessee Department of Transportation, its contractors, and the Tennessee

Highway Patrol did not take the precautions necessary to protect all workers and road

users within the work zone.

Probable Cause

The National Transportation Safety Board determines that the probable cause of

this accident was the driverís incapacitation, owing to the failure of the medical

certification process to detect and remove a medically unfit driver from service.

Contributing to this accident were the lack of planning and coordination between the

Tennessee Department of Transportation, its contractors, and the Tennessee Highway

Patrol regarding work zone projects; the lack of traffic control training, specific to

highway work zone operations, provided to Tennessee Highway Patrol officers; and the

failure of the Tennessee Department of Transportation and its contractors to protect all

work zone personnel and road users.
34 Highway Accident Report

Recommendations

To the Federal Highway Administration:

Review and revise the Manual on Uniform Traffic Control Devices to

provide guidance on coordination with law enforcement personnel used in

traffic control strategies at highway work zones. (H-02-02)

In cooperation and consultation with the National Highway Traffic Safety

Administration, the International Association of Chiefs of Police, the

National Sheriffsí Association, and the American Association of State

Highway and Transportation Officials, develop a model training program

for law enforcement personnel that addresses traffic control strategies at

highway work zones, and encourage the States to adopt it. At a minimum,

the training program should incorporate material from Part VI of the

Manual on Uniform Traffic Control Devices and information concerning

procedures and terminology typically used by highway engineers in

establishing and evaluating work zone operations. (H-02-03)

To the National Highway Traffic Safety Administration:

Work with the Federal Highway Administration to develop a model

training program for law enforcement personnel that addresses traffic

control strategies at highway work zones. At a minimum, the training

program should incorporate material from Part VI of the Manual on

Uniform Traffic Control Devices and information concerning procedures

and terminology typically used by highway engineers in establishing and

evaluating work zone operations. (H-02-04)

To the Tennessee Department of Transportation:

Conduct preconstruction conferences with all parties involved in a work

zone project. As a result of such conferences, produce a written traffic

control plan or project plan agreed to by all parties that defines the lines of

authority and how traffic control and enforcement will be performed for all

types of work zone configurations to be utilized. (H-02-05)
35 Highway Accident Report

To the National Sheriffsí Association, the International Association of Chiefs of 

Police, and the American Association of State Highway and Transportation Officials:

Work with the Federal Highway Administration to develop a model

training program for law enforcement personnel that addresses traffic

control strategies at highway work zones. At a minimum, the training

program should incorporate material from Part VI of the Manual on

Uniform Traffic Control Devices and information concerning procedures

and terminology typically used by highway engineers in establishing and

evaluating work zone operations. (H-02-06)

BY THE NATIONAL TRANSPORTATION SAFETY BOARD

MARION C. BLAKEY

Chairman

CAROL J. CARMODY

Vice Chairman

JOHN A. HAMMERSCHMIDT

Member 

JOHN J. GOGLIA

Member

GEORGE W. BLACK, JR.

Member

Adopted: May 14, 2002

Recommendations

37 Highway Accident Report

Appendix A

Investigation

The National Transportation Safety Board was notified of the Jackson, Tennessee,

accident on July 27, 2000. Investigators were dispatched from the Parsippany, New Jersey,

and Arlington, Texas, offices. Groups were established to investigate highway factors and

motor carrier operations.

Participating in the investigation were representatives of the Tennessee Highway

Patrol and Tennessee Department of Transportation. No public hearing was held; no

depositions were taken.
38 Highway Accident Report

Appendix B

Jackson, Tennessee, Driver Medical Information

Table 1. Information extracted from the driverís medical records by the Medical Officer, 

National Transportation Safety Board.

Date Information Source

10/8/96 A form titled ìPhysical Examination Formî indicates ìNoî for 

the health history categories ìSeizures, fits, convulsions, or 

fainting,î ìExtensive confinement by illness or injury,î and 

ìPermanent defect from illness, disease, or injury.î The form 

indicates ìYesî for ìSuffering from any other diseaseî and 

notes ìCrohnís disease ñ no recent problem.î The form notes 

no abnormalities and is signed by a physician indicating that 

the driver is ìqualified only when wearing corrective lenses.î

Driverís employer

11/26/96 Admission history notes ìÖtruck driver admitted for recent 

onset left lower swelling, pain, and erythema after driving 10 

hours/day for 10 days. Ö 2 nights ago patient was napping, 

woke up ñ when got up to stand noted pain in left groin all the 

way down to the left foot ñ along with left lower extremity 

swelling (pants were very tight around left lower extremity ñ 

tight and painful enough that patient didnít change his pants 

for last 2 days, and didnít stop to eat anywhere because it hurt 

too much to put weight onto his lower extremity ñ also left foot 

swelling to point couldnít wear shoes) continued to drive 10 

hours/day over last 2 days with intermittent stops every couple 

of hours to elevate leg and rest.Öî Past medical history notes 

ìCrohnís disease ñ treated with meds in past none currently, 

intermittent diarrhea about once per month.î Temperature was 

noted as 101.8, weight as 358, and height as 5í11î.

Denver VA Medical 

Center

11/30/96 Interim summary notes admission diagnoses of ì1. Left lower 

extremity cellulitis. 2. History of Crohnís disease. 3. Possible 

obstructive sleep apnea.Öî History notes that the driver 

ìÖpresented to the Denver VA emergency room (ER) with a 

2-day history of left lower extremity swelling, fever to 100.7 in 

the ER, and positive cough with yellow sputum. The patient 

notes pain in his left lower extremity beginning 2 days before 

and then swelling. He did continue to drive his truck for 2 days 

but would pull off to the side of the road because he would 

have such pain. He did not stop to eat during those 2 days 

because it was too painful to leave his truck. He noted 

subjective fevers.Öî

Denver VA Medical 

Center
Appendix B 39 Highway Accident Report

12/2/96 Addendum notes indicate that the driver ìÖon admission, 

gave a history consistent with potential obstructive sleep 

apnea with the presence of snoring as well as some daytime 

somnolence and had obesity as well as 

hypertensionÖunderwent a nighttime pulse oximetry study 

which showed significant desaturations. The patient was to 

have a formal sleep study; however, he reported that he is in 

need of returning to his home in Boise so that he can return to 

his employment. We would have preferred that the patient 

remain an inpatient to complete this evaluation; he stated that 

he needed to be discharged for financial reasons and that he 

would follow up promptly in Boise.Öî

Denver VA Medical 

Center

12/2/96 Discharge instructions note diagnoses of ì(1) left lower 

extremity cellulitis (2) suspected obstructive sleep apnea with 

documented nocturnal desaturations,î discharge medication 

of ìAugmentin 500 mg by mouth 3 times a day for 10 days,î 

and employment status of ìNo work for 1 week secondary to 

need to elevate left leg.î 

Denver VA Medical 

Center

12/4/96 Emergency clinic notes indicate that the driver ìÖpresents 

after admit to Denver VA for left lower extremity 

cellulitisÖnight time desats by pulse ox? sleep apneaÖ 

resents to re-establish care at BVAMC and secondary rash 

from Augmentinî and that he ìÖ needs followup for sleep 

apnea diagnosis (sleep study).î He was prescribed 

azithromycin and ìBenadryl for rash.î

Boise VA Medical Center

12/10/96 Emergency clinic notes indicate that the driverís ìleg is getting 

worseÖAssessment: cellulitis ñ improved, but with continuing 

symptomatologyÖPlan: azithromycinÖreturn tomorrowÖî

Boise VA Medical Center

12/11/96 Emergency clinic notes indicate ìÖcellulitis ñ resolving well 

on azithromycinÖcontinue azithromycinÖwhirlpoolÖdoppler 

studyÖfollowupÖ12/18Öî

Boise VA Medical Center

12/18/96 Physician note indicates ìÖschedule pulmonary consult ñ 

sleep apneaÖscheduleÖclinic 4 months.î

Boise VA Medical Center

4/30/97 Physician note indicates ìÖresolved cellulitisÖreturn to clinic 

5 months.î

Boise VA Medical Center

7/16/97 Physician note indicates ìtruck driver ñ status post motor 

vehicle accident after ëblackoutí 1 week ago.Öhad motor 

vehicle accident while driving his truck on 7/14/97. Canít 

remember a 1 mile distance just before accident. Doesnít 

know whether blacked out or fell asleepÖwas told he might 

have sleep apneaÖPlanÖconsult for sleep apneaÖfollow up 

in 2 weeks.î 

Boise VA Medical Center

7/24/97 Pulmonary clinic note indicates ìÖpatient is a truck 

driverÖhistory of very loud snoring for all of his adult life. 

Patientís brother has witnessed apneas in past.Ödoes have 

daytime sleepinessÖAssessment: Probable obstructive sleep 

apnea syndromeÖhis profession makes him high risk for 

disease-related mortality. Plan 1) I will schedule sleep study 

as high priorityÖ2) No driving until sleep study is done and 

treatment startedÖreturn to clinic with me in pulmonary clinic 

in 3 months.î

Boise VA Medical Center
Appendix B 40 Highway Accident Report

8/13/97 Sleep study results indicate ìSevere obstructive sleep apnea. 

During second half of this study, patient was placed on CPAP 

mask and titrated up to maximum of 10 cm H20. This was 

associated with no significant improvement and complaints by 

the patient of the mask causing complete obstruction of the 

airway. BiPAP mask was attempted and titrated up to 12/5, 

with similar results. Recommendations: Referral to ENT to 

consider surgical therapy for this patientís sleep apnea.î

Boise VA Medical Center

8/21/97 Pulmonary clinic note indicates ìplease refer to ENT clinic 

ASAP ñ patient with severe obstructive sleep apnea. Unable 

to tolerate CPAP mask. Please evaluate for 

uvulopalatopharyngoplasty.íî

Boise VA Medical Center

9/4/97 A note signed by the same physician who signed the 10/8/96 

physical examination form indicates that the driver ìwas 

examined and found to be free of any disability. He is 

physically and mentally fit for safe operation of a commercial 

transportation vehicle.î

Driverís employer

9/19/97 Discharge note following surgery 9/16/97 for obstructive sleep 

apnea (uvulopalatopharyngoplasty, genioglossus 

advancement, hyoidpexy) notes: ìDischarge diagnoses: 1. 

Obstructive sleep apnea. 2. Obesity.î and indicates ìOn 

postoperative day number oneÖHe complained of difficulty 

swallowingÖhe reported complaints of food getting stuck in 

his throatÖOn 9-19-97Öit was found that the patient had 

inadequate laryngeal elevationÖthis left him unable to protect 

his airwayÖheÖwas then taught to use a modification of a 

supraglottic textureÖcould tolerate liquidsÖhad some 

moderate problems with pureed texture Ö discharged home 

Ö scheduled followup to the Boise Fly-In Clinic on 9-23-97.Ö 

should he have difficulties maintainingÖhydration level he 

was instructed to report to the Boise VAÖDischarge 

Medications: Tylenol No. 3 elixirÖinstructed to avoid heavy 

liftingÖfor the next 2 weeksÖinstructed to avoid driving while 

taking narcoticsÖî

Social Work note on 9/18/97 indicates ìÖPatient may be 

discharged tomorrow. His brother will drive him home.Öî

Salt Lake City VA 

Medical Center

9/19/97 Emergency Department note indicates ì3 days ago had 

surgical procedure for sleep apnea ñ discharged from hospital 

5:00 ñ driving back to Boise and at about 6:30 pm developed 

pain in anterior neck and throat, feeling of swelling in anterior 

neck and difficulty swallowing secretionÖdiagnostic 

impression: postoperative swellingÖtransferred to 3E to 

lodgeÖî ENT note indicates ìÖbreathing easily, incision 

intact, airway widely patent, incisions clean dry intact with 

steristrips ñ no hematomaÖadmit as lodging statusÖrecheck 

in AM.î

Salt Lake City VA 

Medical Center

9/21/97 Emergency Notes indicate that driver is ìunable to take 

antibiotics, feels like heís choking.Ödischarged 9/19. 

Readmitted 9/19 with difficulty swallowing/anxiety. Discharged 

9/20. Doing well yesterday morning drank water without 

difficulties.Ö During the day it became more difficult to drink 

water.Ö Plan ñ prop head of bed, sit in Lazyboy recliner. 

Liquid Tylenol #3 or Tylenol Elixer.ÖFollow-up appointment 

already scheduled 9/23.î

Boise VA Medical Center
41 Highway Accident Report

9/23/97 ENT follow-up note indicates that driver is ìstarting to feel 

better. Swallowing improved but still only taking liquids.Östill 

poor laryngeal elevationÖable to clear secretions.Öî 

Boise VA Medical Center

11/24/97 Pulmonary clinic note indicates that the driver ìfailed to follow 

up with me. Still needs repeat sleep studyÖî 

Boise VA Medical Center

8/10/98 Physician note indicates the driver complained of ìmalaise 

and fatigueÖfatigue for 1 month. Diarrhea for 18 years 

unchanged.Öhistory of apnea but after surgery in Salt Lake 

City Utah VA, he is sleeping better and feeling rested.Ö 

Assessment: low energy, fatigue etiology unclearÖî

Boise VA Medical Center

9/16/98 Physician note indicates the driver ìhas increased TSH 

slightly. He has increased weight. He has had increased 

sensitivity of heat. He has diarrhea (Crohnís 

disease).Öweight 358Ödeep tendon reflexes sluggishÖalso 

has pseudomyotonia.ÖAssessment: Probable mild 

hypothyroidism, sleep apnea, resolved status post ENT 

surgery. Plan: begin L-thyroxine 0.025 mgÖreturn to clinic 

Öin 3 monthsÖTSH in 2 months.î

Boise VA Medical Center

10/5/98 A form titled ìPhysical Examination Formî indicates ìNoî for 

the health history categories ìSeizures, fits, convulsions, or 

fainting,î ìExtensive confinement by illness or injury,î and 

ìPermanent defect from illness, disease, or injury.î The form 

indicates ìYesî for ìSuffering from any other diseaseî and 

notes ìCrohnís disease, remission since 1990, 

hypothyroidism.î The form also notes ìknee jerks not elicited 

even against reinforcement ñ likely related to hypothyroid 

state ñ just started replacement.î It is signed by a physician (a 

different physician than signed the other examinations noted 

here) indicating that the driver is qualified with no restrictions.

Driverís employer

8/9/99 A form titled ìPhysical Examination of Driversî indicates ìNoî 

for all health history categories, including ìSeizures, fits, 

convulsions, or fainting,î ìSuffering from any other disease,î 

and ìPermanent defect from illness, disease, or injury.î A note 

indicates ìNo known allergies, on no medications.î The form 

notes no abnormalities, and is signed by a physician (the 

same physician who signed the 10/8/96 and 9/4/97 

examinations) indicating that the driver is ìqualified only when 

wearing corrective lenses.î

Driverís employer

Appendix B