Simulation-Based Impacts Study of Waiting Areas at Left Turns of Actuated Control Intersections

Operational efficiencies at signalized intersections have been greatly affected by the increase traffic volumes. Heavy left turns when present, compound the problems faced at these intersections. Generic optimization methods, vehicle-actuated signal controls and unconventional intersection design have been used to address some of the problems encountered. Lately, waiting areas at left turns are been used to enhance traffic situations at signalized intersections in China. The comprehensive effects of this treatment at left turn waiting areas of actuated controlled intersections were undertaken. A micro-simulation model was developed to estimate the benefits realized when such a treatment is used in conjunction with actuated signal control. The left turn waiting area model was compared with the no build model based on four broad measures of effectiveness. The proposed treatment outperformed in all measures of effectiveness except the number of stops. A user cost and emission cost was undertaken to further quantify the benefits that can be realized with this treatment. A benefit to cost study of installing a left turn waiting area was performed and yielded a benefit to cost ratio of 24:1