More than half of the existing 1,880 intersections that have traffic control signals are semi-actuated. At a semi-actuated intersection, the traffic signal does not automatically alternate between green indications on the main street and the local cross street. Instead, the signals will remain green on the main street until a vehicle or a pedestrian arrives at the cross street. The presence of a vehicle is detected on the cross street by a detector loop embedded in the pavement. The majority of detectors are not set at a sensitivity level to detect the presence of a bicycle. This forces cyclists to either wait for a motor vehicle to arrive in order to actuate the detector, or to dismount and depress the pedestrian push button.

The former Metro Transportation Department initiated a program in 1995 to adjust the sensitivity of the detectors at all semi-actuated intersections to detect bicycles. In the first phase of the implementation the sensitivity was adjusted at approximately 35 intersections that were located on existing bike routes. Three small white dots were also applied to the roadway to inform cyclists where to place their bicycle to be detected by the sensor loop. Since 1995, all new semi-actuated signals have been installed with the sensitivity set to detect bicycles.

However, feedback from the Toronto Cycling Committee and the cycling public indicates that most cyclists are unaware of the purpose of the three "dots", or even that they must be present within the zone of detection in order to change the signal. Unlike the detection of a motor vehicle, which is a passive system for the driver, the success of a bicycle actuating the signal depends on the cyclist not only knowing that there is a detection system, but also how to use it. Even though the sensitivity of the detectors may be adjusted, the effectiveness of the detectors is limited if the cyclist is not properly located in the "actuation zone".

A detailed review of the effectiveness of the loop detectors for bicycles is required to determine where improvements can be made. This might include the use of more distinct pavement markings or at least an improved promotion of the three "dots". Alternative methods of detection should also be investigated as part of this review. Options which might be considered that have been successfully implemented in other jurisdictions include passive technologies such as video detectors or bicycle push buttons so that cyclists can actuate the signal from their normal cycling position on the roadway.