The National Safety Council estimates that 32 percent of all rural crashes occur at intersections. Moreover, approximately one in four fatal crashes occurs at or near an intersection. Because of the high speeds involved, intersection crashes in rural areas are more likely to result in fatalities than are intersection crashes in urban or suburban areas. signalized. Safety literature also indicates that the two most prominent crash scenarios involve left turns and being struck from the rear. Right-angle collisions are a predominant cause of death at signalized intersections.

• Rural drivers tend to drive more quickly than urban drivers.
• Rural drivers are also accustomed to a certain route, so they also are less alert or attentive.
• Rural highways experience high volume, higher speed roads that carry major responsibility for the transport of goods and people in these geographic areas
• Accidents often occur far from help

In a presentation to the TRB Task Force A3A35, Arthur Carter
indicated that 85 percent of intersection crashes were due to driver error, with a
breakdown as follows:

• 27 percent due to driver inattention,
• 44 percent due to faulty perception, and
• 14 percent due to impaired vision.

In Minnesota, statistics show that although 70% of crashes occur in urban areas,
70% of fatal crashes occur in rural areas. During the period 1998–2000, 62% of
intersection-related crashes with fatalities occurred at rural intersections; this high rate is mirrored in many other states.

The primary objective of an Intersection Decision Support system would be to provide drivers on the minor road with information indicating when entry into the intersection is safe, while at the same time, not impeding traffic flow on the high speed major road. reference

Traffic signals are not the best answer

• There is no reduction of total accidents with the introduction of a traffic signal, in fact, rear-end collisions increase
• Signals cause more delays on high-volume roads where they cross low-volume roads, which can lead to crash conditions
• Heavy vehicles traveling at highway speeds are more difficult to stop and more destructive to other vehicles in intersection collisions
• Signals are known to be effective for a narrowly defined set of problems which rarely exist at rural intersections

Clearly, new solutions are needed to address the unique problems found at rural intersections.

Human factors in Intersection Decision Support (IDS)

Intersection Decision Support puts the emphasis on the driver—giving the driver
more power to understand the complex conditions surrounding the vehicle. IDS takes aim at driver error—the most common cause of intersection crashes—by eliminating a primary cause of driver error: insufficient or erroneous information. Better information leads to better decision-making.

• Intersection Decision Support puts the emphasis on the driver
• IDS targets a primary cause of driver error—insufficient or erroneous information
• Better information leads to better decision-making, which ultimate leads to better drivers

Important previous work on many related human-factors issues, including The ITS Institute's HumanFIRST Program at the University of Minnesota, will provide the foundation for the development of the IDS system.

Technology

• Surveillance. IDS will build on work already underway, using radar, GPS, and digital map systems developed in the course of the University of Minnesota's Intelligent Vehicles research
• Computation of vehicle locations will be leveraged and modified to track and predict vehicle trajectories in real time as vehicles approach intersections
• Technology deployment. It is misleading to suggest that deployment of some of the discussed technology may be less expensive than traffic signals. However, the intent is to develop a cost effective system.

The intent of IDS is to develop a cost effective system, including technologies, that does not impede high speed traffic on what is likely a corridor for commercial traffic, and does not increase the occurrence of rear end crashes typical of signalized intersections on high speed rural roads.

Mn/DOT and the U of M also have portable labs that are being used in eight other states — California, Georgia, Iowa, Michigan, Nevada, New Hampshire, North Carolina and Wisconsin — to get driver behavior data from similar intersections.

The State of Minnesota is partnered with California and Virginia in a pooled fund consortium (the Infrastructure Consortium) dedicated to improving intersection safety. The partnership includes three research teams: The Intelligent Transportation Systems Institute at the University of Minnesota, the PATH (Partners for the Advancement of Transit and Highways) Program at the University of California’s Berkeley campus, and the Virginia Tech Transportation Institute at Virginia Polytechnic. Each member of the consortium is tasked with addressing an aspect of intersection safety; Minnesota’s efforts focus on the problem of rural intersection crashes.

Test Sites/State Work

California is focusing on systems integration and the left turn across path problem, particularly in urban areas.

Michigan is hosting a prototype of an early cooperative system to test DSRC and the capability of broadcasting signal information to equipped vehicles.

Minnesota is focusing on lateral direction crashes when minor roads intersect major arterials, particularly in rural areas. Minnesota is currently demonstrating an infrastructure-based rural intersection collision avoidance system and is leading an eight-state, pooled-funds demonstration to note the differences in application across varying geographies and driving characteristics. One example “live field lab” at the intersection of Goodhue County Highway 9 and U.S. Highway 52 in Goodhue County, Minnesota.

Virginia is focusing on near-term deployable approach warnings for traffic signals and signs. Moving forward, Virginia will take the lead in defining the infrastructure-based framework, and will lead the States in working with CAMP to integrate the two frameworks into one cooperative system.

Much of the State research and demonstration has been conducted in cooperation with leading research universities under the Infrastructure Consortium – a research program established under the Intelligent Vehicle Initiative (IVI) for conducting intersection decision support system research focusing on both infrastructure-based and collaborative intersection collision avoidance systems. Three research universities formed the Infrastructure Consortium – the University of California at Berkeley Partners for Advanced Transit and Highways, the University of Minnesota Intelligent Transportation Systems Institute, and the Virginia Polytechnic Institute/Virginia Tech Transportation Institute. Reference