Do Traffic Lights Measure Speed?

[PaulFitz]

Traffic light cameras can measure speed. Additional information is as follows: Electronic Eye: It uses induction lines to sense the pressure from vehicles on the road, collects signals through sensors, and sends them to the central processor for temporary storage in registers. Within the same time interval (during the red light cycle), if two pulse signals are generated simultaneously, it is considered 'valid.' Simply put, if the front wheels cross the line during a red light while the rear wheels remain behind the line, only one pulse is generated. If there are no two consecutive pulses, no photo is taken. When the yellow light is on, the photo system delays for 2 seconds before activating. The system is already active when the red light is on. The system shuts down 2 seconds before the green light turns on, mainly to prevent false captures. There are four types of speed cameras: Fixed speed cameras, mobile speed cameras, average speed cameras (interval speed cameras), and hidden speed cameras.

[DeJulian]

I've been driving for over a decade and I'm quite familiar with traffic lights. Traffic lights primarily control the flow of vehicles—red means stop, green means go—but they don't measure speed. The actual speed measurement is done by dedicated speed cameras or radar devices, which are often installed near traffic light intersections. For example, at busy urban intersections, traffic authorities install these cameras to monitor vehicle speeds and prevent drivers from running red lights or speeding, which could cause accidents. Sometimes when we drive through a traffic light and see a flashing light, we might think it's measuring speed, but actually, it's just the camera taking photos. Speeding can easily lead to rear-end collisions or traffic tickets, especially when taking turns at intersections where high speeds can cause loss of control. I recommend that new drivers pay more attention to their speedometers and avoid relying on traffic lights to judge speed—safety always comes first. These cameras are typically managed by local traffic departments and are quite expensive to install, but they effectively reduce traffic accident rates.

[PatrickLynn]

My personal driving experience tells me that traffic lights are merely signaling tools and do not measure speed; speed detection is handled by electronic devices like fixed or mobile cameras. A friend of mine was fined for speeding at a traffic light intersection, and upon inspection, it turned out to be a separate device in operation, not the light itself. This misunderstanding leads some to think the light is slowing down to measure speed. For safety, it's best to slow down when approaching traffic lights in preparation to stop, as sudden braking or acceleration increases risks. Some urban intersections may incorporate smart systems to optimize traffic flow, but speed detection still requires dedicated hardware. Speeding at intersections is particularly dangerous, increasing the likelihood of collisions with pedestrians, which is why traffic authorities often enhance surveillance to remind drivers. I frequently notice cameras hidden above light poles, reminding myself not to pass through intersections too quickly.

[VanLevi]

As someone who frequently drives on the road, I understand that traffic lights are traffic control devices, not speed detection tools; speed detection is accomplished by cameras. Speeding at intersections may lead to running red lights or accidents, so some places have installed speed detection equipment to deter speeding behavior. When driving, paying attention to your speed can help avoid tickets and protect yourself and others.