Effectiveness of Manual Control of Traffic Signals During Peak Hours

One of the major reasons for congestion is ineffective control at intersections. During the peak hours there has been observed that many signalized intersections in city centers are controlled manually by police officers either by switching off the signal lights or by flashing amber. The objective of the study is to find the effectiveness of manual control compared to traffic signals. Four Junctions which are controlled manually during the peak hours were selected and modelled for three cases, existing posted signal time, updated traffic signal time, and traffic police phase arrangement and cycle time in VISSIM. Webster & Cobbe (1966) model used to design signals and modified to achieve optimum delay. Manual control results lesser delays than the existing signal time case. But updated signal times result even lesser delay than the manual control. When the junction is over-saturated, delays for manual control by traffic police result lesser delay than the existing signal times. Delays for minor road movement delays for signal control have significant reduction of delay than manual control. Daily variation of traffic also affects the junction delays significantly as the fixed cycle time signals are used. Introducing vehicle actuated signals will be an effective solution.