BRT

Bus rapid transit is a high-capacity public transport mode that uses standard or articulated buses on dedicated roadways or lanes to move passengers quickly through urban and semi-urban corridors. Unlike conventional bus services that share road space with mixed traffic, BRT systems prioritize bus movement through physical separation, signal priority, and streamlined boarding infrastructure. A typical BRT corridor can move 10,000 to 20,000 passengers per hour in each direction, approaching the capacity of light rail systems at a fraction of the construction cost.

BRT networks combine several key operational features. Dedicated bus lanes or guideways prevent buses from sitting in congestion; level-boarding platforms or door-to-door height alignment eliminate the delay of ramp deployment; off-board fare collection lets passengers pay before boarding rather than at the driver; and signal preemption gives approaching buses priority at traffic lights. Vehicles are typically 12 to 18 meters long, with some systems using articulated buses (18 meters) to increase capacity. Stations are usually spaced 400 to 800 meters apart, optimizing for both frequency and average speed.

Implementation and variants

True BRT systems exist on a spectrum. Full BRT employs grade separation (median or side lanes with physical barriers) in most or all of the corridor; corridor BRT uses dedicated lanes but may lack full separation; and enhanced bus rapid transit improves service with priority measures but retains some shared roadway segments. Bogota's TransMilenio (opened 2000) and Istanbul's Metrobus are among the highest-capacity implementations, each carrying over 400,000 daily passengers. Smaller cities often adopt lighter-touch versions that deliver speed and reliability improvements without requiring complete roadway reconstruction.

BRT systems rely on frequent service (typically 3 to 5 minute headways at peak periods) and good network integration with feeder buses and other modes. Operational challenges include enforcing lane discipline against informal vendors and parked vehicles, maintaining vehicle reliability under high utilization (buses may run 18 to 20 hours daily), and managing growth in demand that can eventually saturate even dedicated infrastructure. Route geometry matters: tight corners and frequent stops erode the speed advantage; long straight corridors with limited access points deliver the highest average speeds, often 20 to 25 km/h in urban settings.

The term gained currency in the 1990s as planners sought a middle ground between conventional bus systems and fixed-rail investment. It is now standard in transport policy and urban planning; major BRT systems operate in Latin America, Asia, and Africa, with over 200 corridors worldwide. BRT is neither a technology nor a single design standard but rather a service concept combining vehicle, infrastructure, and operational choices to prioritize bus movement and passenger experience within existing street networks.