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Head-On

Crashes

Roadway departures accounted for 57,475 highway deaths between 2016 and 2018. 

Head-on collisions were the most harmful event in 15,744 of these fatalities.

 

Vehicle head-on collisions1 are the most harmful event in approximately 14 percent of all U.S. traffic fatalities each year 

and 27 percent of all roadway departure2 (RwD) fatalities. There were 5,248 average annual RwD fatalities between 

2016 and 2018 where a head-on collision was identified as the 

most harmful event. Figure 1 shows the key characteristics of 

fatalities where RwD head-on collisions are overrepresented in 

crashes. To reduce severe RwD crashes, FHWA recommends 

that State and local agencies consider three broad strategies: 

1. Keep vehicles on the roadway or in their lane, 

2. Reduce the potential for crashes when vehicles 

 leave the roadway, and 

3. Minimize the severity of crashes that do occur. 

This brochure describes solutions that can be used to 

reduce fatal and serious injuries resulting from RwD 

head-on crashes for each of these three strategy areas 

(Ref. Roadway Departure Safety). 

• Pavement Markings – Center line pavement markings help to delineate the road and separate opposing directions 

of travel. The addition of edge lines further assists vehicles with lateral placement within a lane. Widening both 

center lines and edge lines from 4 inches to 5 inches by the Illinois DOT resulted in an annual 14 percent reduction in 

opposite direction fatal plus injury crashes for 2-lane rural roads. Widening edge lines from 4 inches to 6 inches by 

the Kansas DOT resulted in a 53 percent reduction in annual opposite direction fatal plus injury crashes for 2-lane 

rural roads (Ref. Final Report for NCHRP Project 17-66 – publication pending).

• Curve Warning Signs at Horizontal Curves – Installing chevron signs at horizontal curves on rural 2-lane undivided 

roads can produce a 25 percent reduction in non-intersection head-on and opposite-direction sideswipe crashes 

(Ref. Final Report for NCHRP Project 17-66 – publication pending). Installing new fluorescent curve signs or 

upgrading existing curve signs to fluorescent sheeting on rural 2-lane undivided roads can result in approximately an 

18 percent reduction in non-intersection head-on, run-off-road, and sideswipe crashes and a 34 percent reduction in 

non-intersection nighttime head-on, run-off-road, and sideswipe crashes of all severity types (Ref. CMF 

Clearinghouse IDs 2432 and 2435). 

1

 Crashes where the most harmful event is a head-on crash (FARS code 12). 

2

 Crashes in which the vehicle crosses an edge line or center line, or otherwise leaves the traveled way. 

Keeping Vehicles on the Roadway 

Figure 1. Characteristics of RwD fatalities involving head-on 

crashes – FARS data 2016 – 2018.
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• Center Line Rumble Strips – Center line rumble strips are effective treatments to reduce head-on crashes on 

undivided roadways with 2-way traffic. A study based on findings from three states determined that center line 

rumble strips can reduce rural head-on and sideswipe fatal and injury crashes by up to 45 percent and reduce all 

head-on and sideswipe crashes by 37 percent (Ref. Rumble Strips and Rumble Stripes, CMF Clearinghouse IDs 3360

and 3355).

• Friction Treatments - For locations with a history of RwD crashes and where the pavement 

surface is in good condition, high-friction surface treatment (HFST) is an effective solution 

to help reduce head-on crashes. A FHWA research report that assessed the influence of 

HFST on crashes in three states determined that HFST is estimated to reduce head-on and 

sideswipe crashes by 31 percent (Ref. FHWA-HRT-20-061, CMF Clearinghouse ID 10336).

• SafetyEdgeSM - Run-off-road crashes are twice as likely to result in a fatality when a nearvertical pavement edge is exposed (Ref. SafetyEdge). Installing the SafetyEdgeSM during all paving or resurfacing 

projects helps vehicles that drift off roadways to return to the pavement with much less potential for the drivers to 

lose control. This lane departure maneuver can result in crashes with on-coming traffic in the opposing lane. A fivestate study showed the SafetyEdgeSM will reduce head-on crashes by 19 percent on 2-lane rural roads (Ref. FHWASA-17-044, CMF Clearinghouse ID 9217. 

• Center Line Buffer Area – Providing additional lateral separation 

between the two solid center line markings on rural 2-lane 

highways can reduce head-on crashes by as much as 25, 64, and 90 

percent for buffer widths of 2, 4, and 10 feet respectively (Ref. 

Final Report for NCHRP Project 17-66 – publication pending).

• Median Widths – Increasing a 10 feet wide median to 20, 40, 60, 

and 80 feet can reduce rural cross-median crashes up to 16, 40, 57, 

and 69 percent, respectively (Ref. CMF Clearinghouse IDs 4523, 

4534, 4545, and 4555).

• Shoulder Widths – Increasing the width of a shoulder is known to 

help reduce crashes. On 2-lane rural roads, widening an unpaved shoulder to more than 5 feet can reduce the 

number of head-on, run-off-road, and sideswipe crashes by 79 percent (Ref. Report Number K-TRAN:KU-11-1, CMF 

Clearinghouse ID 5404). For paved shoulders on rural 2-lane roads, widening a 6 foot shoulder to 8 foot can reduce 

these crashes by as much as 13 percent (Ref. HSM 1st ed., page 13-11, Ref. CMF Clearinghouse ID 5168). 

• Maintenance to Control Vegetation Growth for Sight Distance – Vegetation adjacent to the road, especially on the 

inside of a horizontal curve, can potentially limit driver’s visibility of approaching vehicles, the road itself, or traffic 

control devices. Ideally, the safety of vehicles operating on the road is enhanced if the driver can see the length of 

required stopping sight distance for the associated speed (Ref. FHWA-SA-07-018).

• Median Barrier – One multi-state study determined that the addition of a median barrier on a rural divided highway 

can be expected to reduce fatal or injury cross median crashes by up to 96 percent (Ref. NCHRP Report 794, CMF 

Clearinghouse ID 7042). 

For additional information, contact Joseph Cheung, FHWA Office of Safety, at joseph.cheung@dot.gov; or Tori Brinkly, 

FHWA Resource Center, at tori.brinkly@dot.gov. 

Publication Number FHWA-SA-21-080 

For Additional Information 

Reducing the Crash Potential When Vehicles Leave the Roadway 

Minimizing the Severity of Crashes 

Roadway Departure 

Safety – FHWA 

Office of Safety

Center line buffer area at TX-21. Source: TTI