7/14/2015
Reed Hollinshead
ITD Communication
208-334-8881
reed.hollinshead@itd.idaho.gov
Paper on low-volume roads earns TRB nod for 35-percent crash reduction in southeastern Idaho
POCATELLO - A 35-percent reduction in crashes resulted in an Idaho Transportation Department (ITD) white paper on safety evaluations for skewed intersections being selected for presentation in a lectern session at the annual meeting of the Transportation Research Board (TRB) in Washington, D.C., in January 2016.
The paper by Dan Harelson, an engineering manager in ITD's office located in Pocatello, also is being presented at the TRB International Conference on Low-Volume Roads in Pittsburgh, Penn. this week.
The paper recounts a system which has reduced crashes by more than one-third in southeastern Idaho since adoption in 2006.
“More importantly, it provides documentation that shows that ITD has a thorough, ongoing review for our intersections,” explained southeastern Idaho District Engineer Ed Bala.
The overall number and severity of crashes at intersections in the region have dropped by about 35 percent in nine years. More than 1,100 intersections were addressed in District 5 (the southeastern Idaho office headquartered in Pocatello), at a cost of approximately $170,000.
Click here for a graphic of the intersection study. Click here for Photo 1 and Photo 2 of Harelson.
Harelson’s paper stems from the understanding that vehicle crashes predominantly occur at intersections, and quite often involve drivers not obeying signs or pavement markings. This puts the responsibility on ITD or the system manager to know the signs and pavement markings at their intersections, and whether the signs are in proper repair.
The paper is based on an intersection audit system Harelson devised when he was the region's traffic engineer. The audit system gives engineers a systematic way to review existing signing and striping at an intersection, decide if any improvements are needed; then prioritize those improvements.
Dr. Mandar Khanal and Dr. Baskar Chitoori from Boise State University were co-authors with Harelson on this paper.
This picture shows what the human eye perceives and when it is recognized. Harelson's research shows that by making sure signs are inside a person's field of vision, and by making sure the signs are up to date and have proper reflectivity, ITD can greatly reduce intersection crashes.
