What happens to a loop detector as sensitivity is increased?

When the sensitivity of a loop detector is increased, it effectively means that the detector becomes more responsive to vehicles passing over it. Specifically, the detector "locks," or places a constant call, indicating that it detects the presence of a vehicle and continuously signals this presence to the traffic signal controller. This is particularly useful in situations with smaller vehicles or lighter loads, where standard sensitivity may not be sufficient for detection.

By increasing sensitivity, the likelihood of mistakenly detecting a vehicle is reduced, allowing for more accurate vehicle detection and minimizing the risk of missed calls at the signal. This adjustment ensures that the detector remains functional and responsive, ensuring that traffic flow is properly managed and that vehicles are given the appropriate right of way.

The other choices present different implications of sensitivity adjustments. For instance, increased sensitivity does not inherently lead to reduced reliability or require additional maintenance; rather, it can enhance the reliability of detection when calibrated correctly. Additionally, while timing responses might seem faster due to increased sensitivity, this does not align with the static concept of "placing a constant call," which is a specific outcome of increased sensitivity.