How Do You Trigger Green Traffic Lights?
• Understand how “demand-actuated” traffic signals work. These are traffic lights that will only turn green when a vehicle is sensed, usually to allow the vehicle to cross a street or make a left turn. At problematic traffic lights, look for a loop of wire buried in the pavement of the road near the stop line. This is called an “inductive-loop traffic detector”[2] that works somewhat like a metal detector, sensing any ferrous metal (steel, iron, etc.). Sometimes these sensors are improperly designed or adjusted, so they don’t pick up on the presence of a smaller vehicle. These sensors do not detect the weight of a vehicle, but rather sense how much it disturbs an electromagnetic field. Once tripped, the signal will begin the light switching process using pre-programmed rules (within 30 seconds, usually less). “Bigger” or more noticable vehicles do not cause the light to turn quicker – your vehicle either trips the switch to begin the process or not. There are ways to make yourself more
