Description

This research paper quantifies the direct impacts of traffic congestion on vehicle fuel consumption and travel time delays along interurban and peri-urban highway corridors in India. Under congested mixed-traffic flow, frequent speed fluctuations, stop-and-go driving cycles, and prolonged idling severely degrade vehicle energy efficiency and inflate travel durations. The study executed field experiments using instrumented test vehicles equipped with real-time fuel flow meters, GPS loggers, and OBD data acquisition systems across varying level of service (LOS) conditions. Data were collected across multiple vehicle classes, including compact cars, SUVs, light commercial vehicles, and heavy multi-axle trucks. Empirical analyses established robust mathematical relationships correlating traffic flow density, speed variance, acceleration/deceleration frequency, and volume-to-capacity (V/C) ratios with incremental fuel consumption and travel time penalties. Results show that fuel consumption per kilometer increases exponentially under severe congestion (LOS E and F), with heavy commercial vehicles experiencing the highest absolute fuel penalty during frequent stop-and-go maneuvers. Furthermore, travel time variability increases significantly, imposing substantial economic costs on logistics and commuter operations. The paper incorporates these empirical findings into the HDM-4 vehicle operating cost framework, offering practical guidance for economic evaluations of road widening, bypass construction, and intelligent transportation system (ITS) implementations designed to smooth traffic flow.