An International Problem.
What causes roadway departure crashes?
There are many contributing factors. Driver fatigue and drowsiness can contribute to ROR crashes; a drowsy driver can be as dangerous as a drunk driver.
In other cases, drivers are inattentive, careless, or distracted, and drift out of the lane and off the road.
Visibility also is an issue, with the majority of accidents happening at night. 70 % of ROR fatalities occur on rural highways, and about 90 % occur on two-lane roads. Rural highways are usually not as well lit as urban roadways.
Inclement weather such as rain, fog, snow, smoke or dust storms also decrease the visibility of pavement markings. In these conditions, drivers may drive off the road accidentally.
Roadway departures account for more than half of all roadway fatalities
The RAC recently reported that in excess of 60% of all regional road fatalities are the result of single vehicle run-off accidents. In Western Australia specifically, the statistics were higher – 70% to December 2014 and 81% in 2013.
Roadway departure fatalities, which include run-off-road (ROR) and head-on fatalities, are a serious problem in the United States. In 2003, there were 25,562 roadway departure fatalities, accounting for 55% of all roadway fatalities in the United States.
That same year:
- More than 16,700 people died in ROR crashes (39% of all roadway fatalities).
- Head-on crashes represented 12% of all fatal crashes.
Shoulder rumble strips (SRS) continue to draw significant research interest around the world, with a particular focus on SRS impact on vehicle operation and manoeuvres, driver safety, and road worker safety. Nevertheless, safety research has established since the 1980s the compelling safety value of SRS.
Oz Rumble strips are a proven, cost effective way to help prevent roadway departure crashes
Oz Rumble strips located on the shoulder of the road have proven to be very effective for warning drivers that they are about to drive off the road. Many international studies also show very high benefit-to-cost (B/C) ratios for shoulder rumble strips, making them among the most cost effective safety features available.
An international study in Nevada found that with a B/C ratio ranging from more than 30:1 to more
than 60:1, rumble strips are more cost effective than many other safety features, including guardrails, culvert-end treatments, and slope flattening. Also, a Maine Department of Transportation (DOT) survey of 50 State DOTs identified a B/C ratio of 50:1 for milled rumble strips on rural interstates nationwide.
Putting It in Perspective
- Approximately 60 percent of all fatal crashes on Australian regional roads were roadway departure crashes.
- In the year to December 2014, 70% of fatalities on Western Australian roads were caused by single vehicle run off accidents. (RAC Australia,Corporate Affairs)
- On average, one roadway departure fatality crash occurred every 23 minutes.
- An average of one roadway departure injury crash occurred every 43 seconds.
- The estimated annual cost of roadway departure crashes is $100 billion.
- Installation of shoulder rumble strips generates an average cost benefit ratio across a range of US States 50:1. (Federal Highway Administration – Office of Safety)
