What should you do at metered ramps to activate the sensors?

At metered ramps, you should pull up to the white stop line in order to activate the sensors. These sensors are designed to detect the presence of a vehicle and then communicate with the traffic signal system to adjust the flow of traffic. When you position your vehicle correctly at the stop line, it allows the sensors to recognize that a vehicle is waiting, which can lead to changes in the signal to facilitate smoother merging onto the highway.

Stopping before the stop line may not provide the sensors with the necessary detection capability, thus potentially delaying your entry onto the highway. Waiting for the signal to change without positioning your vehicle correctly would also not optimize the flow of traffic and could lead to longer wait times. Turning on your headlights is generally not relevant to the activation of ramp meters and does not have any impact on the sensor functions that control the lights.