Intersection Safety Case Study Summary

1. Intersection Safety Case Study Summary Continuous Green T-Intersections A Colorado Success Story FHWA-SA-09-016

2. The Challenge Angle crashes are among the most severe crashes that occur at intersections, including T-intersections. Limited stopping sight distance is a common reason. Colorado Department of Transportation (CDOT) sought an intersection design treatment to reduce the number and severity of crashes at signalized T-intersections.

3. Solution Continuous Green T-intersections (CGT): Main line through traffic passes through without stopping (the top side of the “T”), denoted with continuous green signal Dedicated acceleration and deceleration lanes provided for left-turning movements Concrete median and pavement markings provide lane separation

4. Technical Data Locations: 2 high-crash intersections in Colorado Speed Limits: Ranged from 35 mph to 50 mph Implementation Cost: $300,000 per intersection including the new signals and the raised median work Implementation Time: 3 months per intersection Implementation Issues: CDOT experienced no implementation issues with this countermeasure.

5. Results at Treated Intersections Average Crash Reductions: 96.8% reduction in angle crashes per year 70% reduction in injury crashes per year 60% reduction in total crashes per year

6. For More Information Visit FHWA’s intersection safety web site to download this and other case studies highlighting proven intersection safety treatments from across the country: http://safety.fhwa.dot.gov/intersection Or Contact: Ed Rice Intersection Safety Team Leader, FHWA Office of Safety Phone: (202) 366-9064 E-mail: ed.rice@dot.gov Zane Znamenacek Region 3 Traffic Operations Engineer,Colorado Department of Transportation Phone: (970) 683-6278 E-mail: zane.znamenacek@dot.state.co.us