http://safety.fhwa.dot.gov

Local and Rural Road Safety Briefing Sheets

Low-Cost Safety Improvements

for Rural Intersections

Introduction

The slowing, stopping, crossing, and turning of traffic at intersections represents potential vehicle conflicts, which 

may result in crashes at local and rural intersections. More than 80 percent of rural intersection fatalities occur at 

unsignalized intersections.1,2 Furthermore, rural unsignalized intersections often have high-speed approaches, which 

contributes to the increased severity of any crashes that do occur. 

The most severe crash type at unsignalized intersections is a right-angle crash, which typically occurs when two vehicles 

approaching at a perpendicular angle collide due to one vehicle failing to stop or yield the right-of-way. Out of every 100 

reported angle crashes at unsignalized intersections, it is estimated that between 1 to 3 fatalities and 5 to 15 serious 

injuries result. Therefore, it is important that local and rural road owners understand and know how to identify both the 

safety concern and the types of countermeasures that address unsignalized intersection crashes. 

Rural Intersection Characteristics and Identifying Opportunities

Intersections along rural roadways and intersections owned by local road agencies often have the following 

characteristics:

• Low traffic volumes on minor or all approaches; 

• Unsignalized and mainly stop-controlled;

• Lack of turn lanes and lighting; and

• Skewed angle or limited sight distance. 

Local and rural road owners need roadway information and crash data to help identify intersections with the potential 

for safety improvement. This information can come from sources such as project plans, aerial photos, and State or local 

crash databases populated by crash reports completed by law enforcement. If crash databases are not accessible, local 

and rural road agencies can often use the crash reports themselves, including the crash narrative descriptions, to identify 

certain risk factors and attributes, such as: 

Countermeasure Options

Rural intersection safety can be improved by implementing low-cost improvements that address sight distance, 

intersection recognition, visibility and conspicuity of traffic control devices, and roadway geometry issues. For example, 

adding or enhancing signs, pavement markings, delineators, channelizing islands, and flashing beacons at intersections 

can reduce crash risk. Sightlines should be evaluated with respect to vegetation and roadside features in order to 

establish adequate stopping and intersection sight distances. Intersections that are skewed (e.g., not perpendicular) may 

be modified to intersect at a more desirable angle (closer to 90 degrees) or controlled with regulatory signs or signals. 

• Crash locations or approaches;

• Crash dates and times;

• Crash types and severity;

• Driver and vehicle characteristics;

• Environmental conditions; and

• Sequence of events and contributing circumstances.
The Federal Highway Administration (FHWA) encourages agencies to consider the following treatments, either on a 

systemic basis or at spot locations, although the systemic approach may have a greater cumulative impact on reducing 

fatal and serious injury crashes. The table below shows treatments for stop-controlled intersections, the associated 

crash modification factor (CMF),3

 suggested crash thresholds in which the treatments should be applied, typical cost of 

implementation, and additional considerations. For example, the figure on the following page shows a basic set of sign 

and marking improvements that has the potential to reduce crashes by 30 percent.

Low-Cost Safety Treatments for Stop-Controlled Intersections

Countermeasure Safety Issue 

Addressed

Crash 

Modification 

Factor

Typical 

Minimum

Rural Crash 

Threshold

(All Severities)

Additional 

Implementation 

Factors

Typical 

Implementation 

Cost Range per 

Intersection

Basic set of sign and marking 

improvements (as shown in 

Figure 3)

Recognition of 

stop-controlled 

intersection 

during day or night 

conditions

0.70 4-5 crashes in 5 

years

None $5,000 to $8,000

Either: a) flashing solar powered 

LED beacons on advance 

intersection warning signs 

and STOP signs, or b) flashing 

overhead intersection beacons

Recognition of 

stop-controlled 

intersection 

during day or night 

conditions

0.90 (0.87 for 

right angle 

crashes)

8-10 crashes in 5 

years

None $5,000 to $15,000

Dynamic warning sign which 

advises through traffic that 

a stopped vehicle is at the 

intersection and may enter the 

intersection. Dynamic warning 

sign activated by vehicle presence 

or excessive approach speed.

Limited sight 

distance as a result 

of geometry and/or 

vehicle speed

Unknown 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)

Recognition of 

stop-controlled 

intersection

0.72 

(transverse 

rumble strips)

0.85 (“Stop 

Ahead” 

pavement 

markings)

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 traffic that a “stop” 

condition is ahead

Limited sight 

distance as a result of 

geometry or vehicle 

speed

Unknown 5 running STOP 

sign crashes in 5 

years

Inadequate stopping 

sight distance on the 

stop approach

$10,000 to 

$25,000
Countermeasure Safety Issue 

Addressed

Crash 

Modification 

Factor

Typical 

Minimum

Rural Crash 

Threshold

(All Severities)

Additional 

Implementation 

Factors

Typical 

Implementation 

Cost Range per 

Intersection

Extension of the through edge 

line using short skip pattern 

to assist drivers to stop at the 

optimum point

Recognition of stop 

location

Unknown 5 crashes in 5 

years

Wide throat and 

observed vehicles 

stopping too far back 

from the intersection

Less than $1,000

Retroreflective strips on sign 

posts may increase attention to 

the sign, particularly at night

Recognition of 

stop-controlled 

intersection, 

especially at night

Unknown 5 crashes in 5 

years

Sign visibility 

or conspicuity 

significantly degraded, 

particularly at night

Less than $1,000

Source: Federal Highway Administration, Intersection Safety Implementation Plan Process, November 2009.

Available at: http://safety.fhwa.dot.gov/intersection/resources/intersaf_ipp0709/fhwasa10010.pdf

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
Resources

The following resources provide more details related to intersection safety:

Federal Highway Administration, Intersection Safety webpage: http://safety.fhwa.dot.gov/

intersection/

Federal Highway Administration, Rural Intersection Resources webpage: http://safety.fhwa.dot.

gov/intersection/rural/

In addition, the following publications can be consulted:

Federal Highway Administration, Signalized Intersections: Informational Guide, FHWA-SA-13-027 

(Washington, DC: July 2013).

Available at: http://safety.fhwa.dot.gov/intersection/signalized/13027/fhwasa13027.pdf

Federal Highway Administration, Intersection Safety: A Manual for Local Rural Road Owners, 

FHWA-SA-11-08 (Washington DC: January 2011). 

Available at: http://safety.fhwa.dot.gov/local_rural/training/fhwasa1108/index.cfm

Transportation Research Board, NCHRP Report 500: Guidance for Implementation of the 

AASHTO Strategic Highway Safety Plan, Volume 12: A Guide for Reducing Collisions at Signalized 

Intersections, National Cooperative Highway Research Program (TRB: Washington, DC, 2005). 

Available at: http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_500v12.pdf

Transportation Research Board, NCHRP Report 500: Guidance for Implementation of the AASHTO 

Strategic Highway Safety Plan, Volume 05: A Guide for Addressing Unsignalized Intersection 

Collisions, National Cooperative Highway Research Program (TRB: Washington, DC, 2003). 

Available at: http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_500v5.pdf

1

 University of Minnesota, Center for Transportation Studies website, accessed February 4, 2014:

http://www.its.umn.edu/Research/FeaturedStudies/intersections/

2

 Federal Highway Administration, Intersection Safety: A Manual for Local Rural Road Owners, FHWA-SA-11-08 (Washington DC: 

January 2011). Available at: http://safety.fhwa.dot.gov/local_rural/training/fhwasa1108/index.cfm 3

 A crash modification factor (CMF) is a measure of the safety effectiveness of a particular treatment or design element. A CMF less 

than 1.0 indicates that a treatment has the potential to reduce crashes, while a CMF greater than 1.0 indicates that a treatment has 

the potential to increase crashes. A CMF is determined by dividing the estimated number of crashes with a safety treatment by the 

estimated number of crashes without a safety treatment. For example, if an intersection experiences 10 crashes per year before 

a treatment is applied and 8 crashes per year after a treatment is applied, the CMF for the treatment is 0.8, netting a 20 percent 

reduction in crashes.

FHWA-SA-14-089