Intersection Safety Case Study Summary. Continuous Green T-Intersections. A Colorado Success Story. FHWA-SA-09-016. 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.
Intersection Safety Case Study Summary
Continuous Green T-Intersections
A Colorado Success Story
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.
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
2 high-crash intersections in Colorado
Ranged from 35 mph to 50 mph
$300,000 per intersection including the new signals and the raised median work
3 months per intersection
CDOT experienced no implementation issues with this countermeasure.
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
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
Intersection Safety Team Leader,
FHWA Office of Safety
Phone: (202) 366-9064
Region 3 Traffic Operations Engineer,Colorado Department of Transportation
Phone: (970) 683-6278