Bike-Activated Signal:

Bicyclists often have difficulty crossing streets with high-speed and/or high-volume motor vehicle traffic. The problem is worsened if these streets have multiple lanes. These situations can be greatly improved by placing bike activation devices on the minor street. These give bicyclists preference on demand without causing undue delay to motorists. Activation devices can also be used on a main line street to prolong the green phase and extend the time needed for the bicycle to clear the intersection.

Bicycle loop detectors are the norm as the activation device. Loop detectors can be placed in a traffic lane or bike lane on the side street to trip the signal. These detectors can also be placed on the major street to prolong the green phase and allow a cyclist to clear a wide intersection. It may also be necessary to increase the sensitivity of existing loops, as well as paint stencils on the pavement to point out the most sensitive loop locations to cyclists. Another alternative is the use of push buttons near the roadway such that the cyclist does not have to get off the bike. Video cameras and infrared motion detection sensors are other options but are more expensive.

The City of Seattle, WA, has made extensive use of pedestrian/bicycle crosswalk signals (formerly called half-signals) in locations where bicyclists using residential streets have a need to cross an arterial street at an unsignalized intersection (see case study #40). These signals are actuated by bicyclists (or pedestrians) and stop traffic only on the arterial, leaving the lower volume cross street unsignalized. This allows bicyclists (and pedestrians) to cross safely upon demand without creating unnecessary delays on the arterial street. These crosswalk signals have also been used to facilitate "bicycle boulevards" in various communities. The boulevards are routes to facilitate fast and safe bike movement while discouraging through motor vehicle traffic.