AN ANALYSIS OF ENVIRONMENTAL ADVANTAGES OF FLYOVER CONSTRUCTION OVER SIGNALIZED JUNCTIONS: A CASE STUDY OF TAKHTBHAI FLYOVER

Abstract

Rapid urbanization and gradual rise of motorized transport in the developing regions have played a crucial role in aggravating traffic congestion, consumption of fuel and emission of vehicular emissions posing a deadly concern to the environment and human health. The paper analyzes the environmental benefits of building a flyover as opposed to the use of signalized at-grade intersections based on the Takht Bhai Flyover in Takht Bhai. The study compares the level of grade separation in minimizing traffic delays, vehicle idling, fuel wastage, and pollutants emission to the previous synchronized traffic signal system system at four major junctions in the main market area in the town. Primary data were gathered using a mixed-method design by using the counting technique of traffic counts at various entry and exit points, and classifying vehicles into passenger car unit (PCU) equivalents, travel time was measured, vehicle speeds were measured over a 2-kilometer distance, and the fuel consumption during movement and idling were estimated. Peak-hour measurements were carried out to determine the length of the queue, the cycles of delays and the alteration in the traffic density just prior to and after the construction of the flyovers. The results show that about 35-40 percent of the total traffic volume became redirected to the flyover leading to a decrease of the vehicle delays up to 30 percent and a significant increase in the average traveling velocity which reduced the time spent in idle conditions at intersections. This also led to decrease in idling which directly resulted in fuel consumption and a quantifiable decrease in vehicular emissions and this is an advantage to the environment of continuous traffic flow. The research also takes into account accident statistics and cost of operation, which shows that the mobility and economic efficiency improved, but there are some safety issues and the use of fixed-time signal control at the ground level which restricted the performance at its best on the secondary roads. Generally, the study finds that although flyover construction has a great impact on improving traffic movement and the environmental load in the fast-growing urban centres, its maximum benefits can be achieved only when it is combined with the enhanced traffic regulation systems and new signal control systems.