Warrants for Left-Turn Lanes

Warrants for the installation of separate left-turn lanes were developed. Literature was reviewed, and policies and practices in other states were surveyed. Accident analyses of locations with and without separate left-turn lanes were conducted. Computer simulation was used to determine relationships among traffic delay, load factor, traffic volume, percent left-turns, cycle length, and cycle split. The relationship between left-turn accidents and conflicts was investigated. Warrants were developed involving the following three general areas: accident experience, volumes (based on delay), and traffic conflicts.