Road Transport and Energy (First Revision)
1995 Edition

As outlined in the standard, petroleum-based fuels dominate energy usage in India's road transport. Specifically, oil constitutes approximately 84% of energy consumed within the transport sector, with road transport alone responsible for about 65% of this energy usage and accounting for 77% of the oil consumed in transport. Petrol is primarily utilized by cars and two-wheelers, which consume around 60% of petrol, whereas diesel is chiefly used by trucks, buses, and public transit vehicles, comprising roughly 87% of road transport fuel. Other transport modes like railways depend on coal, oil, and electricity, with increasing electrification reducing oil dependence. Air and maritime transport rely entirely on petroleum fuels. This highlights the heavy reliance on diesel and petrol in the sector, with alternative fuels still in research phases and not yet widely adopted.

The standard emphasizes that each vehicle type has an optimum speed at which fuel consumption per kilometer is minimized; deviations from this speed lead to increased fuel usage. For instance, optimum speeds vary from about 35 km/h for heavy trucks to around 38-40 km/h for passenger cars. Additionally, fuel consumption rises with vehicle load, though fuel efficiency per tonne-kilometer improves as payload increases. Other factors influencing fuel use include uphill gradients, which increase consumption due to gravity, and traffic congestion, which can elevate fuel use by 40-70% because of frequent stops and starts. Idling also wastes fuel, and smoother road profiles along with maintaining optimal speeds help reduce fuel consumption.

Key infrastructure interventions to decrease fuel usage include transitioning from flexible to cement concrete pavements, yielding 5-9% fuel savings for heavy vehicles by reducing pavement deflection losses. Road widening mitigates congestion and prevents stop-and-go traffic, cutting fuel wastage by 40-70%. Designing road vertical profiles to minimize steep slopes reduces fuel consumption associated with climbing gradients. Removing traffic irritants such as octroi posts and railway crossings lowers forced stops and idling. Upgrading surface quality by paving earthen roads with WBM and bituminous layers enhances rolling resistance and vehicle efficiency. Constructing bypasses, ring roads, and expressways diverts heavy traffic from congested urban areas. Coordinated traffic management, including signal optimization and one-way street implementations, further reduces unnecessary fuel consumption.

Traffic congestion substantially increases fuel wastage due to repetitive acceleration, deceleration, and idling. Studies indicate that fuel consumption can escalate by 40% to 70% in congested stop-and-go traffic compared to steady driving conditions. For example, idling fuel consumption ranges from about 9.6 cc/min in small cars to over 35 cc/min in heavy trucks. Major contributors to this wastage are forced halts at intersections, checkposts, and octroi barriers. Effective measures to alleviate this include road widening, traffic signal coordination, removal of encroachments, and educating drivers to turn off engines during extended stops. Hence, managing congestion is critical for minimizing fuel loss.

The standard advocates multiple strategies for vehicle fleet modernization aimed at reducing fuel consumption. These include adopting aerodynamic vehicle designs to reduce air drag, developing more fuel-efficient engines, and utilizing lightweight materials such as plastics, aluminium, and fibre-reinforced composites to lower vehicle weight. Enhancements in suspension and braking systems improve vehicle performance and fuel economy. Increasing the power-to-weight ratio optimizes operational efficiency. The promotion of battery-powered electric vehicles reduces reliance on fossil fuels. Deployment of multi-axle vehicles improves load distribution and fuel efficiency. Use of radial tyres can save 3-5% in diesel consumption. Driver training programs focusing on fuel-efficient driving practices and stricter enforcement of emission controls are also encouraged to reduce harmful emissions and improve overall energy utilization.