Unsignalized Intersections

Dangers

While they may seem quite ubiquitous to the average driver, intersections actually make up a very small part of the total American highway system. Despite this fact, accidents are dramatically more likely to occur at intersections than at other locations along roadways.

According to a study produced by the National Cooperative Highway Research Program in 2003, more than 50 percent of all crashes in urban areas occur at intersections, and more than 30 percent of accidents in rural areas occur at intersections. Furthermore, the chance of collision not only increases at unsignalized intersections but those collisions also become more dangerous. Nearly 35 percent of crashes at unsignalized intersections involve injuries and 9 percent of intersection accidents involve fatalities. In comparison, as few as 6.5 percent of fatalities occur at signalized intersections.

It may not be surprising that unsignalized intersections are far more common in rural areas than in urban areas. Also to be expected, as population and development increases, traffic at unsignalized intersections sees a corresponding increase. If this increase in traffic at the unsignalized intersection hits a critical point, and that occurrence comes to the attention of transportation officials, a stop light may be installed. Thus, while there are currently many more unsignalized intersections in the United States than signalized intersections, signals are becoming more common.

Improvements

Traffic safety officials have two basic methods through which to reduce the risk of collision. Either the situation can be improved for safe drivers or the behavior of risky drivers can be addressed. The former is far easier to address, but there have been efforts to engage the latter, as well. In order to understand efforts to reduce the risk of collision at unsignalized intersections, one must understand all the objectives improving these intersections, then seek to understand the strategies utilized in improving those intersections.

The reasons to improve unsignalized intersections are many, and many of these reasons may not seem obvious to laypeople. This article does not provide a complete list of reasons to improve an intersection, but it does provide some of the most common and important reasons to improve intersections.

First and foremost, traffic engineers seek to reduce the frequency and severity of incidents by changing the geometric design of the intersection (for example, changes to improve driver sight distance). Traffic engineers may also seek to not only improve the availability of gaps in traffic but also to assist drivers in judging gap sizes between cars at the intersection.

...