It came out of nowhere. Another vehicle going way too fast has 

sideswiped you on the Interstate, and even though you’ve braked and 

tried to recover from the skid, your vehicle is going off the road. Trees 

flash by, your brakes screech, and then there’s the impact. Your car 

slides along the guardrail for what seems like ages, kicking up gravel 

and making a terrifying noise. But finally, it comes to a stop. And you’re 

still alive. 

Thousands of Americans have similar experiences every year, and they 

all have one thing in common: roadside safety hardware has saved their 

lives. Roadside safety devices have been proven to significantly reduce 

the number of fatal and serious injury crashes among drivers who 

would otherwise have run off the road and crashed into a potentially 

deadly object.1

 For example, median barriers installed on rural four-lane 

freeways showed a 97 percent reduction in cross-median crashes.2

Roadside safety hardware redirects vehicles that leave the roadway 

away from roadside hazards such as steep drop offs, bodies of water, 

or the roadside itself, which may be lined with fixed objects such as 

trees, bridge piers, retaining walls, or utility poles. Highway engineers 

carefully weigh the placement of roadside safety hardware, and in most 

cases, these devices work extremely well. 

Continuous Improvement: Making Roadside Safety 

Devices Safer 

FHWA, in partnership with the American Association of State Highway 

Transportation Officials (AASHTO), is actively working to improve 

safety on our Nation’s roadways every day. We recognize that a car that 

crashes into anything—even a safety device—can cause an injury or 

fatality, and we are working to find new ways to continuously improve 

the roadside safety devices deployed across the country. 

1 Y. Zou, A.P. Tarko, E. Chen, M.A. Romero, “Effectiveness of cable barriers, guardrails, and concrete 

barrier walls in reducing the risk of injury,” Accident Analysis & Prevention 72 (2014), 55-65. 

2 J.L. Graham et al., NCHRP Report 794, Median Cross-Section Design for Rural Divided Highways 

(Washington, DC: TRB, 2014).

What Is Roadside 

Safety Hardware?

Roadside safety hardware 

refers to devices installed 

alongside the roadway that are 

designed to lessen the severity 

of crashes when a driver runs 

off the road. For example: 

Guardrails redirect vehicles

away from hazardous objects

and unsafe terrain.

Crash cushions help slow

a vehicle down or reduce

the force of impact with a

hazardous obstacle like a

bridge pier.

Breakaway sign, signal,

and light posts break off

at the base so that, when

struck, they go over the

vehicle, landing behind it

rather than on top of it.

These devices are only 

installed when the possible 

consequences of striking the 

device are less harmful than 

striking the other objects next 

to the roadway or hurtling off 

the road into a ravine, a body 

of water, or other hazard. 

When a driver has lost control 

of a vehicle, roadside safety 

hardware is the last line of 

defense. 

ROADSIDE SAFETY HARDWARE: 

The Last Line of Defense 
https://safety.fhwa.dot.gov

CRASH TESTING. To be eligible for Federal highway funding, 

roadside safety hardware installed on the National Highway System 

must be crashworthy, meaning that it has been successfully tested 

in accordance with established national testing requirements. This 

controlled, repeatable testing is conducted based on the criteria 

laid out by these requirements at accredited crash test laboratories. 

These rigorous, standardized crash testing criteria became even 

more stringent under AASHTO’s Manual for Assessing Safety Hardware

(MASH).3

 The new requirements encourage manufacturers to develop 

safety devices that work better, take into account the increasingly wide 

range of vehicle types on the road, and address potential crashes that 

may occur under a more diverse range of conditions. 

INSTALLATION AND MAINTENANCE PRACTICES. FHWA is working 

with State and local agencies to improve how roadside safety 

devices are installed and maintained. FHWA is proactively addressing 

appropriate placement, installation, and maintenance practices of 

roadside safety hardware through a training program offered to State 

and local agencies. This program is funded through the Fixing America’s 

Surface Transportation (FAST) Act and has several different components 

to provide flexibility in meeting the needs of different agencies.4 5

IN-SERVICE PERFORMANCE EVALUATION (ISPE). Roadside hardware

is rigorously tested at laboratories in situations that are intended to 

encompass the majority of possible in-service collision types. State 

ISPE programs provide valuable insights into how these devices 

perform under a wide variety of real-world conditions. By monitoring 

what does and doesn’t work, research engineers can better understand and improve the design features that 

are most effective for improving safety. FHWA, working with four State partners, is currently completing a pilot 

ISPE designed to identify successful practices for: 

 Collecting data on crashes involving roadside safety hardware.

 Communicating among agencies at the state level regarding crash reporting.

 Managing data to maximize the effectiveness of hardware inventory and maintenance practices.

FHWA is committed to preventing deaths and injuries on the Nation’s roadways, and is working with its safety 

partners, State agencies, and the public to address sources of potential danger to drivers, whether on or alongside the 

roadway. For more information, please visit the Countermeasures that Reduce Crash Severity web page. 

3 American Association of Highway and Transportation Officials, Manual for Assessing Safety Hardware (MASH), Second Edition, 2011. 

https://store.transportation.org/item/publicationdetail/2707

4 Based on a total of 51,091 deaths in 1980 and 37,133 deaths in 2017. Source: 2017 data, FARS (see https://crashstats.nhtsa.dot.gov/Api/

Public/ViewPublication/812603). 1980 data, Insurance Institute for Highway Safety, Highway Loss Data Institute 

(see https://www.iihs.org/iihs/topics/t/general-statistics/fatalityfacts/overview-of-fatality-facts) 

5 Federal Highway Administration, Roadside Safety Hardware Identification Methods Report to Congress, 2018. Available at: https://safety.fhwa.dot.gov/

roadway_dept/countermeasures/reduce_crash_severity/id_methods/ch1.cfm. Source of 2017 fatal crashes: 2017 data, 

FARS (see https://www.nhtsa.gov/research-data/fatality-analysis-reporting-system-fars)

FHWA-SA-19-003

ROADSIDE SAFETY HARDWARE: THE LAST LINE OF DEFENSE

Between 1980 and 2017, continuous 

improvements in engineering and design 

have reduced by 47 percent the number of 

fatalities resulting from vehicles crashing into 

guardrails. By comparison, total fatalities 

related to motor vehicle crashes declined 

by 27 percent during the same period.4 In 

2017, in less than one half of one percent 

of all 34,247 fatal crashes on highways, the 

most harmful event is attributed to vehicles 

striking a guardrail terminal.5

568

302

1980 2017

FATALITIES from GUARDRAIL CRASHES

600

500

400

300

200

100

0

-47%