Complex Intersection: Increasing Permeability

The introduction of a collective transport system, such as Bus Rapid Transit (BRT) or a light rail, may radically transform streets and intersections, with the only goal of increased efficiency of the transit service.

These corridors may continue for several blocks without intersections in order to avoid conflicts with crossing traffic. Pedestrians are channeled onto overhead bridges, and cyclists are forced to take long detours.

The illustration above depicts a main corridor designed to prioritize the through-movement of vehicles and mass transit. The central corridor does not intersect with local streets. Vehicles coming from the local street must turn right to proceed.

Cyclists ride in mixed traffic or on sidewalks, increasing the risk of conflict with motorists and pedestrians.

Large corner radii and wide lanes encourage speeding, and fences along the transit corridor prevent pedestrians from crossing it.

Crossing facilities are grade-separated and pedestrians are required to use elevated bridges to cross the street and to access the central boarding island for transit.

Bogota, Colombia

The intersection is redesigned to increase permeability, prioritize pedestrians, and encourage non-motorized uses while  maintaining an efficient transit system.

 Remove overhead bridges and replace them with at-grade crossings at intersections and mid-block locations, allowing pedestrians to directly access the transit stops at grade.

Provide curb extensions and refuge islands to shorten crossing distances.

 Introduce parking-protected cycle tracks and buffered cycle lanes to provide a safer environment for cyclists.

Bidirectional cycle facilities on each side of this wide street reduce the need to cross the transitway and provide a high-quality  corridor for the entire cycle network. Extend ground markings for cycle lanes through the conflict zone of the intersection, matching the width and positioning of the leading cycle lanes.

Remove fences in the median and replace them with planters and rows of trees on each side of the transit way.

 Separate local traffic and through-traffic. Remove curbside parking from the main roadway; instead provide it in the service lane where the speed is limited at 20 km/h.

Recess parking from the intersection. Raise crossings and provide distinct treatments for the service lane to slow speeds and increase visibility between vehicles, cyclists, and pedestrians.

Manage or restrict turns across oncoming traffic to improve reliability of the transitway and overall safety. See: Operational and Management Strategies.

Yinchuan, China