Warrants for the installation of left-turn phasing were developed. A review of literature was conducted along with a survey of the policies of other states. Field data of delays and conflicts were taken before and after installation of exclusive left-turn signalization. Left-turn delay studies were conducted at intersections with varying volume conditions. Analysis of the effect on accidents of adding a left-turn phase was made. The relationship between left-turn accidents and conflicts was investigated. Other types of analysis concerning gap acceptance, computer simulation, capacity, and benefit-cost ratios were also performed.
It was found that exclusive left-turn phasing significantly reduced left-turn accidents and conflicts. Left-turn delay was only reduced during periods of heavy traffic flow. Warrants were developed dealing with the following four general areas:
- accident experience,
- volumes, and
- traffic conflicts.
Digital Object Identifier
Agent, Kenneth R., "Development of Warrants for Left-Turn Phasing" (1976). Kentucky Transportation Center Research Report. 867.