A method is described for determining the effect of right- turning vehicles (left-hand rule of the road) on the capacity of traffic-signal-controlled intersections, and ways are suggested for setting the intergreen period or an early cut-off period to cater for right-turning movements. Four cases are considered; with and without exclusive lanes for the right-turning vehicles, and with and without opposing traffic during the phase in which the right-turners are permitted to move. The method has been derived using a simple theoretical model to represent a signaled junction with right-turning vehicles discharging through gaps in the opposing flow. The method also makes use of experimental data on discharge rates of right-turning vehicles turning through various degrees of curvature. A worked example is given to illustrate the use of the method.
Abstract