Spring 2005

  Optimizing Signal Timing- An Efficient Way To Handle Traffic Congestion

Md. Al – Amin Sarker, Md. Moinul Hossain

Every year millions of dollars are lost in the global economy due to traffic congestion. Long hours spent on congested roadways are draining away valuable time, energy and money from the economy. Overcrowding of motorways represents the greatest bottleneck in raising the economy’s productivity, hampering it from further potential growth. Furthermore, additional social costs in term of environmental pollution as well as medical expenses due to traffic congestion related symptom, such as higher stress level experience by commuters, are depleting the limited resources available to our society.

The above discussion clearly indicates that delay should be reduced to increase productivity and to minimize environmental pollution. the most economic way of this delay reduction is to redesign the signal timing because this design is not associated with spending money as well as consuming longer time. Only readjustment of signal timing is sufficient for this purpose. Hence, to optimize the signal timing for reducing delays has been taken as the main objective of this study. An intersection has been chosen to achieve the goal of this study. this selected intersection comprises Mirpur road, Manik mia Avenue & Farm gate road with 9 movements.

This study suggests that the new timing of the signal reduces total delay for all movements 27.05% (Morning peak) & 16.30% (Evening peak) than the existing one. Particularly for movement 2 and movement 4 for morning peak  & movement 2 & movement 5 for evening peak, delay reduces most. In case of morning peak, it is found from the analysis that for movement 2 and movement 4 delays reduce 40.59% and 39.77% respectively. On the other hand during evening peak, movement 2 & movement 8 – delays reduces 22.33% & 21.95% respectively from their existing conditions. The presented figures clearly justify the improvement of the junction performance in new signal timing.

Besides the signal timing, some other problems are also identified which also affects the operation of the intersection. These problems may not only play a vital role to increase delay at intersection but also increase the chances of road crashes. Pedestrian safety is also associated with them. Such types of problems arise from improper road marking, illegal parking, unplanned buses stoppage, illegal footpath usage etc. Photographs have been placed to show these problems. Suggestions have been given to handle these problems by using scientific judgment and applying engineering knowledge.