Intersection Safety Case Study Summary FHWA-SA Red-Light Running: All-Red Clearance Intervals and Larger Signal Lenses A Michigan Success Story

1 The Challenge Red-light running causes more than 170,000 injuries and 900 deaths per year 1. Driver speeding and distracted driving, as well as inability to see the traffic control device in time to comply are common problems. Clearance intervals, together with increasing the size of the signal lenses, have been shown to improve intersection safety. Cities of Detroit and Highland Park sought simple, low-cost safety treatments to increase driver compliance with traffic signals, and reduce the number and severity of crashes at urban signalized intersections. 1. Federal Highway Administration Red-Light Running Web Site (2008),

2 Solution All-red interval and larger signal lens: Replace red, yellow, and green 8-inch signal lens with 12-inch signal lens Added an all-red clearance interval ranging from 1-2 seconds 2 2. Calculated using Institute of Transportation Engineers (ITE) guidelines.

3 Technical Data Location: – 33 high-crash locations in the cities of Detroit and Highland Park, Michigan Speed Limits: – Ranged from 35 mph to 40 mph Implementation Cost: – Total corridor cost of $2.3 million at $70,000 per intersection Implementation Time: – 6 months Implementation Issues: – The cities experienced no implementation issues with these countermeasures

4 Results at Treated Intersections Average Crash Reductions: – 75.7% reduction in angle crashes per year – 45.5% reduction in injury crashes per year – 33.3% reduction in total crashes per year

5 Visit FHWA’s intersection safety web site to download this and other case studies highlighting proven intersection safety treatments from across the country: Or contact: For More Information Tapan Datta Transportation Research Group Wayne State University Phone: (313) Ed Rice Office of Safety (HSSD) Federal Highway Administration Phone: (202)