AASHTO Journal, 2 October 2015
More of Minnesota’s rural areas have been getting intelligent transportation systems in recent months at high-risk intersections, in a state Department of Transportation effort to reduce crashes and improve safety.
MnDOT is installing “rural intersection conflict warning systems” at 54 high-risk locations around the state. Those sites ranked poorly, it said, for such factors as visibility before the intersection, traffic volume, whether there is a railroad or commercial development close by, previous crash history and road distance from the last stop sign.
At the bottom of this story is a video the agency prepared about the dangers at many rural intersections, and the use of sensor-triggered warning signs to alert drivers about oncoming traffic they might not see.
Here is a list of the locations where MnDOT is installing that warning system.
The systems are used at intersections where stop signs control traffic, but where drivers may not be able to see traffic very well that could be on roads crossing from the side or around curves. The systems use a combination of traditional signing plus electronic informational signs, flashing lights that turn on when traffic is approaching the intersection and sensors that trigger those lights to flash.
This MnDOT video explains the need in Minnesota’s rural areas for such technology, and shows drivers how the system works.
“The system gives real-time warning to motorists approaching a stop sign that there is traffic approaching, and also warns drivers on the road without the stop sign that a vehicle is stopped or entering the intersection,” said Ken Hansen, RICWS project manager.
Hansen said people tend to think there are fewer crashes in rural areas since they aren’t as populated as urban areas, but about 66 percent of fatal crashes in the state happen on rural roads. This is due to varying terrain, inconsistent sightlines such as trees and vegetation near the travel lanes, roadway skews and motorists driving at higher speeds.
“Injuries in rural areas are usually serious injuries and fatalities,” Hansen said. “Emergency response often takes longer because of the distance between cities. We think these systems will make a difference in reducing crashes and saving lives.”
In 2014, 324 fatal crashes occurred in the state and 214 of those were in population areas of less than 1,000. The number of personal injury crashes in population areas of less than 1,000 was higher than the injuries in areas with populations of 250,000 and greater.
A National Highway Traffic Safety Administration study found that 62 percent of crashes in rural stop-controlled intersections were caused by drivers stopping and looking, but not seeing the other vehicle and proceeding into the intersection. A MnDOT study found that 26 percent of right-angle crashes at stop-controlled intersections were caused by drivers failing to stop.
With the warning systems, motorists on a major road will see a standard “Entering Traffic” sign, a “When Flashing” sign and a flashing light as they approach and pass through the intersection. The flashing light will activate only when vehicles are present on the connecting minor road.
Motorists on the minor road will see an illuminated LED “Traffic Approaching” sign and “When Flashing” sign with dual flashing lights. The dual flashing lights will only come on when traffic is approaching, while the LED “Traffic Approaching” is constantly illuminated.
“Drivers should always obey the stop signs as they approach an intersection, but the added technology is designed to be an additional safety message,” Hansen said.