Low-Cost Safety Enhancements for 

Stop-Controlled and Signalized Intersections 

U.S. Department of Transportation 

Federal Highway Administration 

FHWA-SA-09-020
Table of Contents 

1. Introduction ........................................................................................................................................................... 4 

2. Stop-Controlled Intersections ............................................................................................................................ 5 

Signing and Pavement Marking Enhancements........................................................................................................................................5 

Crash Problem....................................................................................................................................................................................................5 

Countermeasures.............................................................................................................................................................................................5 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges.......................................................................................................................................................................6 

J-Turn Treatments at Stop-Controlled Intersections on Multi-Lane Divided Arterial Highways .................................8 

Crash Problem....................................................................................................................................................................................................8 

Countermeasures.............................................................................................................................................................................................8 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges.......................................................................................................................................................................8 

3. Signalized Intersections....................................................................................................................................... 9 

Traffic Signal, Signing, and Pavement Marking Countermeasures at Signalized Intersections.....................................9 

Crash Problem....................................................................................................................................................................................................9 

Countermeasures.............................................................................................................................................................................................9 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges....................................................................................................................................................................10 

4. Lighting at Unlit or Poorly Lit Intersections ................................................................................................... 12 

Crash Problem.................................................................................................................................................................................................12 

Countermeasures..........................................................................................................................................................................................12 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges....................................................................................................................................................................12 

5. High-Frictions Surfaces ...................................................................................................................................... 13 

Crash Problem.................................................................................................................................................................................................13 

Countermeasures..........................................................................................................................................................................................13 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges....................................................................................................................................................................13 

6. Speed Reduction Countermeasures on High Speed Approaches to Intersections ................................ 14 

Crash Problem.................................................................................................................................................................................................14 

Countermeasures..........................................................................................................................................................................................14 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation Factors, 

and Estimated Cost Ranges....................................................................................................................................................................15 

7. Multiple Countermeasures Applied at the Same Intersection ................................................................... 16 

8. The Systematic Approach—Concept .............................................................................................................. 17 

9. Systematic Deployment—The Process ........................................................................................................... 19 

10. Summary............................................................................................................................................................... 19 

2 
List of Tables 

Table 1: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Countermeasures at Stop-Controlled Intersections.............................7 

Table 2: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Countermeasures at J-Turn Stop-Controlled Intersections.................8 

Table 3: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Countermeasures at Signalized Intersections .....................................10 

Table 4: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Lighting Countermeasures at Unlit or Poorly Lit Intersections ........12 

Table 5: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Skid Resistance Countermeasures at Intersections with 

High Rates of Low-Friction Crashes ...................................................................................................................13 

Table 6: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated 

Implementation Cost Ranges for Countermeasures at Stop-Controlled Intersections with 

High-Speed Approaches ......................................................................................................................................15 

Table 7: Example of a Typical State Distribution of Crashes at Rural State Stop-Controlled Intersections 

(5 Years Crash Data)...............................................................................................................................................18 

Table 8: Example of Typical State Crash Severity for Various Intersection Types.....................................................18 

List of Figures 

Figure 1: Examples of Basic Low-Cost Countermeasures for Stop-Controlled Intersections – Double Up 

Oversize Warning Signs, Double STOP Signs, Traffic Island on Stop Approach (if feasible), 

Street Name Signs, Stop Bars, and Double Warning Arrow at the Stem of T-Intersections ......................6 

Figure 2: Turn Restrictions at Multi-Lane Highways.. ........................................................................................................8 

Figure 3: Example Intersection with Basic 12 inch Lens, Back Plates and a Signal Head per Lane ..........................9 

Figure 4: New Design for Intersection Lighting Layout..................................................................................................12 

Figure 5: New Design for Wide Roadway Intersection Lighting Layout. .....................................................................12 

Figure 6: Lane Narrowing Using Rumble Strips................................................................................................................14 

Figure 7: Intersection Categories for Low-Cost Countermeasure Consideration......................................................17 

3 
1. INTRODUCTION 

Nationally, at least 21 percent of all fatalities, 52 percent of injuries, and 45 percent of 

property damage crashes occur at or near intersections. Recognizing the size of the 

problem, many States have identifed intersection safety strategies to help achieve 

a statewide fatality or crash reduction goal within their Strategic Highway Safety Plans. 

A systematic approach involving the application of 

low-cost, efective countermeasures at a large number 

of intersections which are experiencing crashes can 

collectively reduce substantive numbers of statewide 

intersection crashes and fatalities. Intersections with 

crash experience are defned as those with crash levels 

at or above defned crash level thresholds, (usually 

described in terms of number of crashes per intersection 

occurring over a 5-year period) where the application of 

the low-cost countermeasure will be cost efective. Most 

intersections experiencing crashes meet the minimum 

Manual on Uniform Trafc Control Devices (MUTCD) 

standards, but added countermeasures are needed to 

reduce future crash potential. 

The purpose of this document is to present information 

on suggested efective, low-cost intersection 

countermeasures developed using intersection safety 

research results and input from an intersection safety 

expert panel. These low-cost countermeasures can be 

applied to a large number of intersections with a high 

frequency of crashes using a systematic approach. The 

net impact of such an approach can produce signifcant 

reductions in statewide intersection crashes, fatalities, and 

serious injuries. Low-cost countermeasures are defned as 

those ranging from $1,000 to $50,000 per intersection. 

The suggested low-cost countermeasures and the 

intersection conditions where these countermeasures can 

be most cost-efectively deployed are as follows: 

Stop-Controlled Intersections 

• Signing and pavement marking countermeasures at 

stop-controlled intersections with a high frequency of crashes. 

• J-turn treatments at stop-controlled intersections on multi-lane 

divided arterial highways with a high frequency of angle crashes. 

Signalized Intersections 

• Traffic signal, signing, and pavement marking 

countermeasures at signalized intersections with a high frequency 

of crashes. 

Stop-Controlled and Signalized 

Intersections 

• Lighting at unlit or poorly lit intersections with a high frequency and 

proportion of crashes occurring during hours of darkness. 

• High-friction surfaces on high-speed intersection approaches with 

a high frequency and proportion of wet pavement crashes. 

• Speed reduction on high-speed approaches to intersections with a 

high frequency of severe crashes involving speed. 

These sets of countermeasures were developed by 

integrating available research fndings and input from 

intersection safety experts and practitioners in the Federal 

Highway Administration (FHWA) intersection focus states. 

A description of the crash problem and deployment 

characteristics for each of the countermeasures follows. 

4 
 

2. STOP-CONTROLLED INTERSECTIONS 

Signing and Pavement Marking Enhancements 

Crash Problem 

The major crash type at stop-controlled intersections 

is a right angle crash involving a vehicle entering the 

intersection from the stop approach and a vehicle on the 

through approach. In these crashes, most of the vehicles 

on the stop approach stop or at least slow down to 

under 10 mph before pulling out. However, many drivers 

involved in these crashes make poor decisions regarding 

the available safe gaps between vehicles on the through 

road. Inattentive or distracted drivers, speeding, and 

physical limitations of the intersection contribute to future 

crash potential. 

Countermeasures 

The set of low-cost countermeasures for stop-controlled 

intersections is designed to increase drivers’ alertness 

to the presence of the intersection and reduce 

potential conficts with other entering vehicles. These 

countermeasures are primarily intended for deployment 

at stop-controlled intersections with either single 

through lanes or multiple undivided through lanes. 

Countermeasures have been classifed as basic or 

supplemental. Basic countermeasures are those that are 

usually very low in unit cost and efective in terms of 

reducing future crash potential and should be considered 

at all intersections having crashes above a defned crash 

threshold. Supplemental countermeasures are targeted 

to intersections with crash levels considerably above the 

crash threshold or the intersection has specifc types of 

crashes that the countermeasure can address. 

Basic Countermeasures 

The basic set of countermeasures should be considered 

as a package of minor improvements consisting of all of 

the following: 

Low-Cost Countermeasures for the Through Approach 

• Doubled up (left and right), oversize advance intersection warning signs, 

with street name sign plaques. 

Low-Cost Countermeasures for the Stop Approach 

• Doubled up (left and right), oversize advance “Stop Ahead” intersection 

warning signs. 

• Doubled up (left and right), oversize STOP signs. 

• Installation of a minimum 6 ft. wide raised splitter island on the stop 

approach (if no pavement widening is required.). 

• Properly placed stop bar. 

• Removal of any foliage or parking that limits sight distance. 

• Double arrow warning sign at stem of T-intersections. 

Supplemental Countermeasures—Intersections 

with Higher Crash Frequencies 

In addition to the basic package of countermeasures, 

additional individual countermeasures can be 

considered based upon higher frequencies of crashes 

beyond the crash threshold for basic countermeasures 

or at intersections that have crash types that the 

countermeasure can address. 

• Installation of a minimum 6 ft. wide raised splitter island on stop 

approach which requires pavement widening. (See FHWA-HRT-08-063 

for further design and performance information.). 

• Either a) fashing solar-powered LED beacons on advance intersection 

warning signs and STOP signs or b) fashing overhead intersection 

beacons. 

• Dynamic warning sign to advise through trafc that a stopped vehicle is 

present and may enter the intersection. 

• Transverse rumble strips across the stop approach lanes in rural areas 

where noise is not a concern and running STOP signs is a problem. 

(Use “Stop Ahead” pavement markings if noise is a concern.). 

• Dynamic warning sign to advise high-speed approach trafc that a 

stopped condition is ahead; use this countermeasure when vehicles 

running the STOP sign is a problem. 

• Extension of the through edge line using short skip pattern may assist 

drivers to stop at an optimum point; this countermeasures is used on 

intersections with very wide throats in which stopped drivers have 

difculty stopping at the correct location. 

• Refective stripes on sign posts may be used on signs with degraded 

conspicuity due to sign clutter or competing background features to 

increase attention to the sign, particularly at night. 

Supplemental countermeasures should be considered in 

addition to the basic set of countermeasures and not in 

lieu of the basic countermeasures on those intersections 

with higher crash frequencies or those that possess 

certain physical characteristics that the countermeasure is 

designed to impact. 

5 
Suggested Mountable Curb 

Figure 1: Examples of Basic Low-Cost Countermeasures for Stop-Controlled Intersections – Double Up Oversize Warning Signs, Double STOP Signs, Traffic Island 

on Stop Approach (if feasible), Street Name Signs, Stop Bars, and Double Warning Arrow at the Stem of T-Intersections 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation 

Factors, and Estimated Cost Ranges 

It is assumed that the existing traffic control devices 

at intersections under consideration for improvement 

are MUTCD compliant and usually consist of a single 

standard size intersection warning sign for each through 

direction of travel and “Stop Ahead” and STOP signs 

on the stop approaches. Even with these signs a high 

frequency of crashes may exist at the intersection. 

Applying the complete set of sign and markings, 

defined previously under “Basic Countermeasures,” to 

the intersection is estimated to reduce future crashes 

by 30 percent (crash reduction factor (CRF) of 40). This 

estimate was developed by an expert intersection safety 

panel using past effectiveness research findings in 

combination with engineering judgment. 

Crash reduction factors for supplemental stop-controlled 

intersection countermeasures have been taken from 

the FHWA Toolbox of Countermeasures and Their Potential 

Effectiveness to Make Intersections Safer and other FHWA 

publications. The CRFs, typical crash thresholds for 

application, additional implementation factors, and 

estimated cost ranges for each of the countermeasures 

are provided in Table 1. 

6 
 

 

-

Countermeasure 

Crash 

Reduction 

Factor 

Typical 

Urban Crash 

Threshold 

Typical 

Rural Crash 

Threshold 

Additional 

Implementation 

Factors 

Typical Imple 

mentation 

Cost Range per 

Intersection 

Basic set of sign and marking 

improvements 

40% 10 crashes 

in 5 years 

4-5 crashes 

in 5 years 

None $5,000 to $8,000 

Installation of a 6 ft. or greater raised 

divider on stop approach (installed 

separately as a supplemental counter 

measure ) 

15% 20 crashes 

in 5 years 

10 crashes 

in 5 years 

Widening required 

to install island 

$25,000 

to $75,000 

(pavement 

widening but no 

ROW required) 

Either a) fashing solar powered LED 

beacons on advance intersection 

warning signs and STOP signs or b) 

fashing overhead intersection beacons 

10% (13% for 

right angle 

crashes) 

15-20 crashes 

in 5 years 

8-10 crashes 

in 5 years 

None $5,000 to 

$15,000 

Dynamic warning sign which advises 

through trafc that a stopped vehicle 

is at the intersection and may enter the 

intersection 

Unknown 20-30 crashes 

in 5 years 

10-20 crashes 

in 5 years 

5 angle crashes in 

5 years and inadequate 

sight distance from the 

stop approach 

$10,000 to 

$25,000 

Transverse rumble strips across the stop 

approach lanes in rural areas where 

noise is not a concern and running 

STOP signs is a problem (“Stop Ahead” 

pavement marking legend if noise is 

a concern) 

28% (transverse 

rumble strips) 

15% (“Stop 

Ahead” 

pavement 

markings) 

5 running 

STOP sign 

crashes in 

5 years 

3 running 

STOP sign 

crashes in 

5 years 

Inadequate stopping 

sight distance on the 

stop approach 

$3,000 to 

$10,000 

Dynamic warning sign on the stop 

approach to advise high-speed 

approach trafc that a stopped 

condition is ahead 

Unknown 8 running 

STOP sign 

crashes in 

5 years 

5 running STOP 

sign crashes 

in 5 years 

Inadequate stopping 

sight distance on the 

stop approach 

$10,000 to 

$25,000 

Extension of the through edge line 

using short skip pattern may assist 

drivers to stop at the optimum point 

Unknown 10 crashes 

in 5 years 

5 crashes 

in 5 years 

Wide throat and 

observed vehicles 

stopping too far back 

from the intersection 

Less than $1,000 

Refective stripes on sign posts 

may increase attention to the sign, 

particularly at night 

Unknown 10 crashes 

in 5 years 

5 crashes 

in 5 years 

Sign visibility or 

conspicuity 

signifcantly degraded 

particularly at night 

Less than $1,000 

Table 1: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Countermeasures at 

Stop-Controlled Intersections 

The entire set of basic signing and marking 

countermeasures should be the primary improvement 

considered at stop-controlled intersections with a high 

frequency of crashes. One exception is stop-controlled 

intersections on divided multi-lane highways in which 

J-turn treatments (see next section) are the preferred 

countermeasure. 

Additional supplemental countermeasures beyond the basic 

sign and marking enhancements should be considered at 

those intersections which either have much higher levels of 

crashes beyond the basic sign and marking crash thresholds 

or have other intersection crash concerns identifed in 

Table 1 that may be addressed by a given countermeasure. 

The crash threshold levels in Table 1 may be adjusted to 

refect the following: entering trafc volumes (low volume 

intersections may have a lower threshold); and/or diferences 

in severity rates (e.g., fatalities per 100 crashes) between 

urban and rural stop-controlled intersections. Refer to the 

Systematic Approach section of this document for further 

information on adjusting crash thresholds. 

7 
J-Turn Treatments at Stop-Controlled Intersections on Multi-Lane Divided 

Arterial Highways 

Crash Problem 

The major crash type at stop-controlled divided arterial 

highway intersections is a crash involving a vehicle 

entering the intersection from the stop approach and 

a vehicle travelling on the through approach, usually 

on the far side of the intersection from the right. The 

crash typically occurs after the vehicle from the stop 

approach has entered the divided median portion of the 

intersection and is attempting either to cross or turn left 

onto the far side of the arterial. While sign and marking 

countermeasures may impact this problem, they are not 

considered as effective as eliminating the through and 

left-turn movement from the stop approach and replacing 

them with a right-turn only J-treatment using a median 

break downstream. 

Countermeasures 

The low-cost countermeasure for multi-lane divided 

arterial intersections is to eliminate left-turn and 

through movements from the stop approach, forcing 

all vehicles to turn right. This is accomplished by adding 

minor channelization to the stop approach and in the 

median and supplementing the channelization with 

appropriate signs and markings. Drivers desiring to turn 

left or proceed through the intersection can make a 

U-turn a short distance downstream and continue on 

with their intended movements. Further information on 

J-turn designs and performance may be obtained from 

National Cooperative Highway Research Program (NCHRP) 

Project 15-30. This treatment is also referred to as either 

Superstreet or a Restricted Crossing U-turn intersection. 

Figure 2: Turn Restrictions at Multi-Lane Highways 

24 Total J-Turn Conflict Points 

4 Crossing 12 @ Main Intersection 

8 Weaving 10 Merge 

10 Diverge 4 @ U-Turns 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional 

Implementation Factors, and Estimated Cost Ranges 

Crash reduction factors for left-turn restrictions from stop approaches to divided highways have been taken from 

NCHRP Project 15-30, which included an evaluation of J-turn projects in North Carolina. Those evaluations concluded 

that there was a 100 percent decrease in cross-path crashes, a range of 72 to 84 percent reduction of frontal impact 

crashes, and an overall intersection reduction of total crashes of 43 to 53 percent. 

Countermeasure Crash Reduction 

Factor 

Typical 

Urban Crash 

Threshold 

Typical 

Rural Crash 

Threshold 

Additional 

Intersection 

Concern 

Implementation 

Cost Range per 

Intersection 

J-turn modifications on 

high-speed divided arterials 

100% cross path, 72-84% 

frontal impact, 

43-53% all crashes 

4 angle crashes 

in 5 years* 

4 angle crashes 

in 5 years* 

Ability to make U-turn 

within about 1⁄4 to 1⁄2 

mile of intersection 

$5,000 to 

$50,000 

* If a highway section has a series of stop-controlled intersections with a high collective number of angle crashes, it is preferable to treat the problem on a system 

basis addressing all of the stop-controlled intersections rather than improving a few intersections that have isolated high numbers of angle crashes. 

Table 2: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Countermeasures at 

J-Turn Stop-Controlled Intersections 

8 
3. SIGNALIZED INTERSECTIONS 

Trafc Signal, Signing, and Pavement Marking Countermeasures at Signalized Intersections 

Crash Problem 

The major severe crash type at signalized intersections 

is a right-angle crash where one vehicle violates the 

red signal. Rear-end crashes occur with a much higher 

frequency but are much less severe than angle crashes. 

Two other concerns at signalized intersections are crashes 

involving left turn-opposing fow crashes and pedestrian 

crashes. 

Countermeasures 

The low-cost countermeasures for signalized 

intersections are identifed below. Countermeasures 

have been classifed as basic or supplemental. Basic 

countermeasures are those that are usually very low in 

unit cost and efective in terms of reducing future crash 

potential. Supplemental countermeasures are targeted to 

intersections with specifc crash concerns. 

Basic Countermeasures 

• Twelve-inch LED lenses on all signal heads. 

• Back plates on all signal heads (optional refectorized border). 

• A minimum of one trafc signal head per approach lane. 

• Trafc signal yellow change interval and all red interval timing adjusted 

to be in accordance with the Institute of Transportation Engineers (ITE) 

timing standards. 

• Elimination of any late night fashing operations. 

Figure 3: Example Intersection with Basic 12 inch Lens, Back Plates and a Signal 

Head per Lane 

The basic set of countermeasures should be considered as 

a package of minor improvements consisting of all of the 

above countermeasures. 

Supplemental for Special Conditions 

In addition to the basic package of countermeasures, 

additional individual countermeasures can be 

considered based upon higher frequencies of crashes 

beyond the crash threshold for basic countermeasures 

or at intersections that have specifc crash types that 

the countermeasure can address. 

• Potential change of permitted and protected left-turn phases to 

protected-only for intersections which have high numbers of left turnopposing fow crashes, three or more opposing approach lanes, or high 

opposing volumes with few acceptable turning gaps. 

• Advance cross street name signs for high-speed approaches on arterial 

highways. 

• Advance left and right “Signal Ahead” oversize warning signs for 

isolated trafc signals or intersections where the signal heads are not 

readily visible due to alignment or sight distance obstructions. 

• Supplemental signal heads where normally placed signal heads may 

be difcult to identify due to: sight distance limitations, horizontal 

curvature, or other obstructions; or, exceptionally wide intersections 

where a near side signal is needed. 

• Advance detection control systems at isolated high-speed signalized 

intersections that have red-light running angle crashes. 

• Signal coordination countermeasures on high-volume arterials with 

closely spaced trafc signals and frequent mainline stopping due to 

poor or no signal coordination. 

• Pedestrian countdown signals, at intersections with high pedestrian 

activity or multiple pedestrian crashes. 

• Exclusive pedestrian phasing at intersections with numerous 

pedestrian-turning vehicle conficts. 

• Higher visibility cross walks and advanced pedestrian warning signs 

at intersections with high pedestrian activity or multiple pedestrian 

crashes. 

9 
 

 

 

 

-

Countermeasure Crash Reduction Factors, Threshold Levels, Additional 

Implementation Factors, and Estimated Cost Ranges 

It is assumed that the existing trafc signals at the intersection are MUTCD compliant and consist of at least dual 

signal heads on each approach. The estimated crash reduction factor for the combined basic countermeasures is a 

30 percent reduction in all crashes. This estimate was developed by an expert intersection safety panel using past 

efectiveness research fndings for individual countermeasures combined with engineering judgment. 

Crash reduction factors for supplemental enhancements for special conditions have been taken from the FHWA 

Toolbox of Countermeasures and Their Potential Efectiveness to Make Intersections Safer and other FHWA research 

publications and are indicated in Table 3. 

Countermeasure 

Crash 

Reduction 

Factor 

Typical Urban 

Crash Threshold 

Typical Rural 

Crash Threshold 

Additional 

Implementation Factors 

Implemen 

tation Cost 

Range per 

Intersection 

Basic set of signal and 

sign improvements 

30% 20 crashes 

in 5 years 

10 crashes 

in 5 years 

None $5,000 to 

$30,000 

Change of permitted and 

protected left-turn phase 

to protected-only 

41-48% of 

left turn 

crashes 

5 left turn 

movement crashes; 

3 or more opposing 

through lanes; 

minimal turning 

gaps available 

5 left turn movement 

crashes; 3 or more 

opposing through 

lanes; minimal 

turning gaps 

available 

None $5,000 to 

$10,000 

Advance cross street 

name signs for highspeed approaches on 

arterial highways 

Unknown 20 crashes in 5 

years 

10 crashes in 5 

years 

High-speed approaches on 

four or more lane arterial 

highways 

$1,000 to 

$5,000 

Advance left and right 

“Signal Ahead” warning 

signs for isolated trafc 

signals 

22% 20 crashes in 5 

years 

10 crashes in 5 

years 

Isolated trafc signal with 

one or more miles between 

signals; or trafc signals that 

are not readily visible due 

to highway alignment or 

obstructions 

$1,000 

Supplemental signal face 

per approach 

28% 20 crashes in 5 

years 

10 crashes in 5 

years 

Signal faces obstructed 

by horizontal alignment; 

or exceptionally wide 

intersections (>100 ft) where 

a near side signal is needed 

$5,000 to 

$15,000 

Advance detection 

control systems 

40% 

(injuries) 

5 angle crashes 

in 5 years 

5 angle crashes in 

5 years 

Isolated high-speed (45mph 

or greater) signalized 

intersections 

$15,000 

Signal coordination 32% 20 crashes in 

5 years per 

intersection 

10 crashes in 5 years 

per intersection 

Arterials with closely spaced 

(about 1/2 mile maximum) 

signals 

$5,000 to 

$50,000 

Pedestrian countdown 

signals 

25% 

(pedestrian 

crashes) 

2 pedestrian 

crashes in 5 years 

2 pedestrian crashes 

in 5 years 

None $5,000 to 

$15,000 

10 
Implemen - Crash Additional Typical Urban Typical Rural tation Cost Countermeasure Reduction Implementation Crash Threshold Crash Threshold Range per Factor Factors Intersection 

Separate Pedestrian 

Phasing 

34% (pedestrian 

crashes) 

2 pedestrian crashes 

in 5 years involving 

a turning vehicle 

2 pedestrian crashes 

in 5 years involving a 

turning vehicle 

None $5,000 to 

$15,000 

Pedestrian Ladder or 

cross-hatched crosswalk 

and advanced pedestrian 

warning signs 

15% (pedestrian 

crashes) for signs 

Unknown for 

crosswalk 

2 pedestrian 

crashes in 5 years 

2 pedestrian crashes 

in 5 years 

None $1,000 to 

$3,000 

Table 3: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Countermeasures at 

Signalized Intersections 

The typical crash threshold levels in Table 3 may be refned to refect the following: entering trafc volumes (low-volume 

intersections may have a lower threshold); and/or diferences in severity rates (e.g., fatalities per 100 crashes) between 

urban and rural signalized intersections. Further information on adjusting thresholds may be found in the “Systematic 

Approach” section of this document. 

The basic set of signal and signing countermeasures should be the primary improvement considered at signalized 

intersections with a high frequency of crashes. 

Additional supplemental countermeasures beyond the basic signal and sign enhancements should be considered at 

those intersections which either have much higher levels of crashes beyond the basic signal and sign improvement 

crash thresholds or have other intersection concerns identifed in Table 3 that may be addressed by a given 

countermeasure. 

11 
4. LIGHTING AT UNLIT OR POORLY LIT INTERSECTIONS
 

Crash Problem 

Crashes that occur during darkness are typically more 

severe than daylight crashes. Major problems associated 

with unlit or poorly lit intersections (e.g. only one light 

per intersection) include reduced ability to recognize that 

an intersection is being approached, reduced ability to 

navigate turning movements properly, and degradation of 

the ability to recognize other vehicles and pedestrians in 

or entering the intersection. 

Countermeasures 

The low-cost countermeasure for unlit or poorly 

lit intersections with a high frequency and rate of 

night crashes is lighting. Typical example layouts for 

intersection lighting are shown in Figures 4 and 5. 

States should follow their design policy for intersection 

lighting installations. 

Figure 4: New Design for Intersection Lighting Layout 

Source: Federal Highway Administration, Informational Report on Lighting Design for Midblock Crosswalks, FHWA-HRT-08-053 (Washington, DC: April 2008). 

Figure 5: New Design for Wide Roadway Intersection Lighting Layout 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation 

Factors, and Estimated Cost Ranges 

The crash reduction factor at unlit intersections with high frequencies and rates of night crashes is 50 percent of night 

crashes. The crash reduction factor for improving lighting at poorly lit intersections is estimated by an expert safety 

panel as 25 percent of night crashes. 

Typical threshold crash levels for considering lighting countermeasures at intersections are provided in Table 4. 

Additional 

Intersection 

Concern 

Crash Reduction 

Factor 

Typical Urban 

Crash Threshold

Typical Rural 

Crash Threshold Countermeasure 

Implementation

Cost Range per

Intersection
 


 


 

New or upgraded 

Lighting 

50% (NEW), 

25% (UPGRADED) 

of night crashes 

10 night crashes in 5 years 

and a night /total crash 

ratio above the statewide 

average for urban unlit 

intersections 

5 night crashes in 5 years 

and a night/total crash 

ratio above the statewide

average for rural unlit 

intersections 

None $5,000 to 

$15,000 

Table 4: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Lighting Countermeasures 

at Unlit or Poorly Lit Intersections 

12 
5. HIGH-FRICTION SURFACES 

Crash Problem 

Crashes that occur when the pavement is wet on 

approaches with speed limits of 45 mph or more may be 

attributed to increased stopping distances due to low skid 

numbers and/or severe rutting in the wheel paths that 

might induce hydroplaning. 

Countermeasures 

The low-cost countermeasure for intersections with 

higher frequencies of wet pavement crashes and above 

average wet/total crash rates include increasing the 

friction characteristics on intersection approaches which 

have low skid numbers and eliminating any severe wheel 

path rutting. 

One way transportation ofcials can increase pavement 

friction beyond what is attainable through traditional 

techniques is by using new high-friction surfacing 

systems. These systems are a combination of resins and 

polymers (usually urethane, silicon, or epoxy) and a binder 

topped with a natural or synthetic hard aggregate. 

Microtexture, macrotexture, and the durability of that 

texture distinguish these overlays from standard asphalt 

and concrete pavement surfaces. High-friction 

surfacing systems typically use much smaller and 

harder aggregates, such as calcined bauxite, slag, or 

other synthetic aggregates. These aggregates are 

generally less than 6.0 mm (0.23 inch) in diameter 

and have high skid resistance. The small and hard 

aggregate makes the overlay much more resistant 

to wear and polishing. The resin or polymer binder 

combination locks the aggregate frmly in place, 

creating an extremely rough, hard, durable surface 

capable of withstanding everyday roadway demands 

such as heavy braking and snowplowing. The 

rougher texture and greater surface area increase the 

pavement’s friction. 

The length of approach to apply skid resistance 

surfaces is variable dependent on approach speeds, 

sight distance, and expected queue lengths at 

signalized intersections. A minimum 300 feet of 

approach is recommended for through high-speed 

approaches to stop-controlled intersections. In 

addition, signifcant wheel rutting (2 inches in depth or 

greater) should be eliminated before applying any skid 

resistant surface. 

Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation 

Factors, and Estimated Cost Ranges 

Crash reduction factors for skid-resistant surfaces on high-speed (i.e., 45 mph or greater) intersection approaches with 

a high frequency and rate of wet pavement crashes and either (1) a ribbed tire skid number of 30 or less, (2) wheel 

path rutting of at least 2 inches in depth, or (3) both, is 50 percent of wet pavement crashes (The FHWA Toolbox of 

Countermeasures and Their Potential Efectiveness to Make Intersections Safer). 

Typical threshold crash levels for considering friction countermeasures on high-speed approaches to intersections are 

provided in Table 5. 

Countermeasure Crash Reduction 

Factor 

Typical Urban 

Crash Threshold 

Typical Rural 

Crash Threshold 

Additional 

Intersection 

Concern 

Implementation 

Cost Range per 

Intersection 

Skid resistance 

surface 

50% (wet pavement 

crashes only) 

8 wet pavement 

crashes in 5 years, 

a wet/total crash 

ratio above the 

statewide average 

wet/total crashes for 

intersections 

8 wet pavement 

crashes in 5 years, 

a wet/total crash 

ratio above the 

statewide average 

wet/total crashes for 

intersections 

High-speed 

approaches 

(45mph or greater) 

and a ribbed tire 

skid number of 

about 30 or less. 

$20,000 to 

$50,000 

Table 5: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Skid Resistance 

Countermeasures at Intersections with High Rates of Low-Friction Crashes 

13 
6. SPEED REDUCTION COUNTERMEASURES ON HIGH-SPEED 

APPROACHES TO INTERSECTIONS 

Crash Problem 

Intersection approaches where drivers commonly enter 

the intersection at excessive speeds can potentially 

increase the severity of crashes. In addition, higher 

approach speeds may make it more difficult for some 

stopped drivers at stop-controlled intersections to 

identify safe gaps to enter the intersection. Another 

concern is intersections with high speeds on the 

through approaches and limited available sight distance 

from the stop approach. 

Countermeasures 

The countermeasures are primarily intended for 

consideration on the through approaches at stopcontrolled intersections. However, they may also be 

considered, after careful analyses, for high-speed 

approaches at signalized intersections. Minimal 

information is available concerning the crash reduction 

factors for speed reduction countermeasures. A number 

of countermeasures have performed well under limited 

levels of deployment. However, additional deployments 

may yield different results. These countermeasures 

may be cautiously deployed and complemented with 

evaluations to determine if the desired results have or 

have not been obtained. 

The low-cost countermeasures for intersections with 

a high frequency of high-speed vehicle crashes on 

approaches include a number of options, as follows: 

•	 Lane narrowing using rumble strips parallel to the edge lines, as shown 

in Figure 6. (See FHWA-HRT-08-063, “Two Low-Cost Safety Concepts for 

Two-Way Intersections on High-Speed Two-Lane, Two-Way Roadways” 

for further design and performance information.). 

•	 Lane narrowing using raised pavement markers in lieu of rumble strips 

on approaches where noise issues or bicycle safety concerns associated 

with rumble strips cannot be addressed. 

•	 Dynamic warning signs on the through approach warning drivers 

traveling at speeds above a set threshold to slow down. 

•	 Peripheral transverse pavement markings at a spacing of 4 markings 

per second. (See “Peripheral Transverse Pavement Markings for Speed 

Control,” by Bryan Katz, at http://scholar.lib.vt.edu/theses/available/ 

etd-05172007-135959/unrestricted/KatzPhDDissertation.pdf.). 

•	 Slow or speed limit pavement marking legends highlighted within a gray 

or black colored box on the pavement and supplemented with advance 

intersection warning signs with advisory speed plates. (See FHWAHRT-08-063 for further performance information.). 

•	 High-friction surface applied to the approaches (approximately 300 feet 

in advance) and through the intersection. 

Figure 6: Lane Narrowing Using Rumble Strips 

14 
Countermeasure Crash Reduction Factors, Threshold Levels, Additional Implementation 

Factors, and Estimated Cost Ranges 

Crash reduction factors based upon limited research, typical crash thresholds for application considerations, and 

additional intersection concerns that need to be addressed for each of the countermeasures are provided in Table 6. 

Countermeasure 

Crash 

Reduction 

Factor 

Typical Urban 

Crash Threshold 

Typical Rural 

Crash Threshold 

Additional 

Intersection Concern 

Implemen -

tation Cost 

Range per 

Intersection 

Lane narrowing using 

pavement marking and 

shoulder rumble strips 

Lane narrowing using 

pavement marking and 

raised pavement markers 

Peripheral Transverse 

pavement markings 

Dynamic speed warning 

sign on the through 

approach to reduce speed 

“Slow” pavement 

markings 

High-Friction Surface 

10 speed-related 

crashes in 5 years 

10 speed-related 

crashes in 5 years 

10 speed-related 

crashes in 5 years 

10 speed-related 

crashes in 5 years 

10 speed-related 

crashes in 5 years 

10 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

5 speed-related 

crashes in 5 years 

$20,000 to 

$40,000 

$5,000 to 

$10,000 

$3,000 to 

$5,000 

$10,000 

$2,000 to 

$5,000 

$20,000 to 

$50,000 

Free of noise and bicycle 

issues – single through lane 

Single through lane 

31% 

Unknown 

but 

probably 

less than 

31% 

Unknown 

30% 

Unknown 

25% 

(All crashes) 

Table 6: Crash Reduction Factors, Typical Crash Thresholds, Additional Application Factors, and Estimated Implementation Cost Ranges for Countermeasures at 

Stop-Controlled Intersections with High-Speed Approaches 

Except for the high-friction surface countermeasure, countermeasures should be considered as singular treatments with 

the selection of the countermeasure based upon specifc intersection characteristics, crash types and frequencies, costs, 

and crash reduction factors. The high-friction surface countermeasure may be combined with other countermeasures 

to yield more efective results. 

15 
7. MULTIPLE COUNTERMEASURES APPLIED AT 

THE SAME INTERSECTION 

A number of intersections will have more than one set of crash characteristics that can be impacted 

by more than one countermeasure. Estimates of the overall efectiveness of the combined 

countermeasures may be needed. There are a number of methods to estimate the combined 

efectiveness of multiple countermeasures. A suggested methodology follows. 

The overall crash reduction factor (CRFt) at intersections with multiple countermeasures 

(basic plus supplemental) can be estimated by applying the following formula: 

CRFt = 1 – (1- CRF1 )(1- CRF2)(1- CRF3) ...

Where,

CRFt = Total CRF

CRF1 = CRF for the frst countermeasure

CRF2 = CRF for the second countermeasure

CRF3 = CRF for the third countermeasure 

As an example, for a stop-controlled intersection that has the basic sign and markings (CRF-40) 

and fashing solar powered beacons (CRF-10), the total estimated CRF is 1-(1-.40)(1-.10) = .46 

An intersection that has multiple countermeasures in which one countermeasure only impacts 

a portion of the total crashes requires a slightly more complicated calculation. As an example, 

if a stop-controlled intersection has basic sign and marking countermeasures (CRF-40) and 

lighting (CRF-50) and 25 percent of the crashes occur at night, the total estimated CRF for 

crashes is .75[1- (1-.40)]+.25[1-(1-.40)(1-.50)] = .475 

16 
 

8. THE SYSTEMATIC APPROACH—CONCEPT
 

The systematic approach is the reverse of the 

conventional highway safety improvement program 

approach. The conventional approach starts with the 

identification of high-crash intersections and then 

selects countermeasures to impact crash patterns at 

the intersections. The systematic approach starts with 

defining a set of specific low-cost countermeasures and 

searches the crash data base to identify intersections 

where they can be deployed cost effectively on rural 

State, stop-controlled intersections. 

Crash frequencies per intersection, expected 

crash severity (fatalities per 100 crashes), type of 

traffic control at the intersection (STOP sign, traffic 

signal), countermeasure costs, and the expected 

crash reductions resulting from the use of low-cost 

countermeasures all have to be considered to determine 

the optimum use of limited funds, particularly if the goal 

is to maximize the reduction of fatal or severe crashes at 

intersections. 

Figure 7 identifies the eight intersection types in which 

low-cost countermeasures should be considered for 

application. 

Each of these eight categories has a distinct distribution 

of crashes per intersection and severity (fatalities per 

100 crashes) for each type of crash that a given low-cost 

countermeasure is designed to impact. 

A minimum of 5 years of crash data is recommended to 

identify intersections with higher levels of crashes. Crashes 

are not uniformly distributed throughout the universe 

of intersections. A substantial portion of statewide 

intersection crashes may occur at only a very small 

number of intersections that have a higher frequency 

of crashes per intersection. (As an example, 25% of 

the statewide crash problem at rural stop-controlled 

intersections may be concentrated on only 3% of the rural 

stop-controlled intersections which have high frequencies 

of crashes). Low-cost countermeasures can be targeted 

to this small number of intersections and impact a 

substantial portion of the statewide crash problem. 

All Intersection Crashes 

State Roads 

Rural 

Traffic 

Signal 

Traffic 

Signal 

Traffic 

Signal 

Traffic 

Signal 

STOP 

Sign 

STOP 

Sign 

STOP 

Sign 

STOP 

Sign 

Urban Rural Urban 

Local Roads 

Figure 7: Intersection Categories for Low-Cost Countermeasure Consideration 

17 
A typical statewide distribution of rural State, stopcontrolled intersections with one or more crashes over 

the past 5 years is shown in Table 7. Most States should be 

capable of developing similar tables from their Crash Data 

System using basic software such as ACCESS. 

Number of 

Crashes per 

Intersection 

Number 

of Inter -

sections 

Cumulative Cumulative 

100 and greater - - 0.00% - 0.00% 

50 – 99 4 4 0.08% 266 2.23% 

30 – 49 5 9 0.19% 448 3.75% 

20 – 29 29 38 0.78% 1,095 9.16% 

10 – 19 125 163 3.36% 2,685 22.47% 

5 – 9 416 579 11.94% 5,372 44.96% 

4 251 830 17.12% 6,376 53.36% 

3 387 1,217 25.10% 7,537 63.08% 

2 779 1,996 41.16% 9,095 76.12% 

1 2,853 4,849 100.00% 11,948 100.00% 

Total 4,849 4,849 100.00% 11,948 100.00% tionstersecnI tencerP t encerPrashes C

Table 7: Example of a Typical State Distribution of Crashes at Rural State StopControlled Intersections (5 Years Crash Data) 

In the example above, there were 4,849 stop-controlled 

intersections that had at least one crash in the past 5 

years. There are many more intersections on the State 

system, but the number of intersections with no crashes 

can not be identifed from the crash data base. Overall 

there were 11,948 crashes at the 4,849 intersections. Of 

these intersections, 579 (12 percent of total) intersections 

had fve or more crashes per intersection, resulting in 

5,372 crashes, or almost 45 percent of all statewide 

crashes. At a higher threshold, 163 intersections had 10 or 

more crashes per intersection resulting in 2,685 crashes 

or over 22 percent of the statewide crashes. Once a 

minimum crash threshold is established, applying lowcost countermeasures at those intersections with crash 

frequencies at or above the threshold would impact a 

substantial portion of all statewide rural crashes at stopcontrolled intersections on State roads. 

In addition to identifying intersections with higher 

frequencies of crashes per intersection, the severity of 

crashes (fatalities per 100 crashes) can difer signifcantly 

by area (i.e., rural or urban) and type of trafc control and 

needs to be considered. For example, crashes at rural stopcontrolled intersections are typically much more severe 

than crashes at either urban stop-controlled intersections 

or any type of signalized intersections. 

The defnition of severity used in the analysis should be 

aligned with the intersection goal of the Strategic Highway 

Safety Plan. If the goal of the Plan is to reduce intersection 

fatalities the severity should be defned in terms of fatalities 

per 100 crashes; if the goal is to reduce fatalities and 

incapacitating injuries, the severity should be defned in 

terms of fatalities and incapacitating injuries per 100 crashes. 

The severity of any given crash is dependent on a number of 

factors, many of which are independent of the intersection 

characteristics. Factors such as the types of vehicles in the 

crash, the kinematics of the crash, and the age and gender 

of the drivers can greatly infuence the potential for a crash 

to result in either property damage or a fatality. Statewide 

fatalities or fatalities and incapacitating injuries per 100 

similar crashes for a given type of intersection and crash 

type provide a more stable estimate of the severity. 

The severity of crashes varies signifcantly by ownership, 

urban/rural area, and type of trafc control. Table 8 provides 

an example of diferences in severity (fatalities per 100 

crashes) by type of trafc control, area, and ownership for 

a typical State. 

Traffic Control Road Ownership Fatalities 

per 100 Crashes 

State Rural 4.40 

State Urban 1.14 

Local Rural 1.24 

Local Urban 0.51 

State Rural 1.60 

State Urban 0.59 

Local Rural 0.72 

Stop 

Stop 

Stop 

Stop 

Signal 

Signal 

Signal 

Signal Local Urban 0.39 

Table 8: Example of Typical State Crash Severity for Various Intersection Types 

As an example, if the application of low-cost 

countermeasures at State rural stop-controlled intersections 

is expected to prevent 100 crashes from occurring, 4.4 lives 

are projected to be saved. Similarly, if the same low-cost 

countermeasure applied at State urban stop-controlled 

intersections is also expected to prevent 100 crashes from 

occurring, only 1.14 lives are projected to be saved. If a 

State has a goal to reduce intersection fatalities and has 

100 urban and 100 rural stop-controlled intersections each 

with fve crashes per intersection, and can only improve 100 

intersections it is clear that improving the rural intersections 

has more life saving potential; however, if the urban 

intersections had 20 crashes per intersection the decision to 

maximize lives saved becomes much more difcult. 

18 
9. SYSTEMATIC DEPLOYMENT—THE PROCESS

1. Select the low-cost countermeasures to deploy using a systematic process. It could be all or a few of those previously listed. As an example, assume that 

improving signs and markings at stop-controlled intersections is one of the countermeasures selected. 

2. Identify candidate intersections for countermeasure application. Sign and marking countermeasures can be implemented on four categories of intersections: 

State urban, State rural, local urban and local rural stop-controlled intersections. For each of these categories, the fatalities per 100 crashes and number of 

crashes per intersection (Tables 7 and 8) are developed from 5 years of data for the type of crash the low-cost countermeasure is intended to impact (all 

crashes for sign and marking countermeasures at stop-controlled intersections). Establish a crash threshold for each category based upon probable cost 

efectiveness of the countermeasure; the relationship between the crashes per intersection, cumulative intersections, and cumulative statewide crashes; 

the estimated funds available; and the number of intersections where the State may realistically implement countermeasures over the next few years. The 

threshold may be adjusted to consider entering AADT if that data is readily available. As an example, in general, a threshold of 5 crashes in 5 years for rural 

stop-controlled intersections may be established, but intersections with a low AADT, say less than 2000, could have a threshold of 4 crashes. Candidate 

intersections are those at or above the threshold. 

3. Assess the potential impact. Using the number of candidate intersections at or above the threshold, the fatalities per 100 crashes, the countermeasure crash 

reduction factor, and the estimated number of candidate intersections that will be improved, calculate the statewide estimated cost and estimated crashes 

reduced and lives saved. 

4. Perform steps 1 through 3 for all of the identifed countermeasures and collectively assess cost and potential crash and fatality reductions. Compare results 

to the intersection safety goal in the Strategic Highway Safety Plan and if necessary adjust list of countermeasures, crash thresholds, intersections to be 

considered for improvement, and costs to better align with the intersection goal. 

5. Field review the candidate intersections. The candidate intersections need to be feld reviewed to determine if the low-cost countermeasures are appropriate 

to deploy at the intersection. In the example of the sign and marking countermeasure for a stop-controlled intersection, in addition to determining if the 

identifed sign and marking basic countermeasures are appropriate, the intersection should also be checked to see if other crash thresholds for supplemental 

countermeasures, lighting, skid resistance, and speed control are met and, if so, whether additional countermeasures should be implemented. 

6. Tabulate the results of the feld review and prepare plans to implement the countermeasures. 

7. Implement countermeasures, monitor and evaluate, comparing actual results to estimates. 

10. SUMMARY

Several FHWA intersection focus states are currently using the systematic process to deploy low-cost intersection 

countermeasures to lower statewide intersection fatalities. 

Low-cost countermeasures are recommended for those intersections that presently meet at least minimum MUTCD 

standards but are still experiencing a high frequency of crashes above a certain threshold. Countermeasures 

for stop-controlled and signalized intersections have been categorized as basic or supplemental. Basic 

countermeasures are those that are usually very low in unit cost and collectively efective in terms of reducing 

future crash potential. Supplemental countermeasures may be somewhat higher in unit costs compared to the 

basic countermeasures, but increase overall efectiveness when combined with the basic countermeasures to 

reduce crashes. Supplemental countermeasures should be considered at those intersections that have levels 

of crashes considerably higher than the threshold levels, high levels of specifc crash types, or specifc physical 

characteristics or defciencies that the countermeasure is intended to mitigate. 

A number of low-cost intersection countermeasures have been identifed that are efective in reducing future 

crashes. Because the countermeasures are relatively low cost, they can be deployed at a substantial number 

of intersections with high numbers of crashes. The result of such a deployment can reduce statewide levels of 

intersection crashes and fatalities. 

19 
For More Information 

Jeffrey Shaw 

Intersections Program Manager 

FHWA Office of Safety 

202.738.7793 jeffrey.shaw@dot.gov 

U.S. Department of Transportation 

Federal Highway Administration 

FHWA-SA-09-020 Revised July 2020