Call us on:+86-760-22382116

Traffic Light

Source:

Traffic lights, also known as traffic signalstraffic lampstraffic semaphoresignal lightsstop lightsrobots (in South Africa), and traffic control signals (in technical parlance),[1] are signalling devices positioned at road intersectionspedestrian crossings, and other locations to control flows of traffic.

The world's first, manually operated gas-lit traffic signal was short lived. Installed in London in December 1868, it exploded less than a month later, injuring[2] or killing[3] its policeman operator. Traffic control started to seem necessary in the late 1890s and Earnest Sirrine from Chicago patented the first automated traffic control system in 1910. It used the words "STOP" and "PROCEED", although neither word lit up.[4]

Traffic lights alternate the right of way accorded to users by displaying lights of a standard colour (red, amber (yellow), and green) following a universal colour code. In the typical sequence of colour phases:

  • The green light allows traffic to proceed in the direction denoted, if it is safe to do so and there is room on the other side of the intersection.

  • The amber (yellow) light warns that the signal is about to change to red. In a number of countries – among them the United Kingdom – a phase during which red and yellow are displayed together indicates that the signal is about to change to green.[5] Actions required by drivers on a yellow light vary, with some jurisdictions requiring drivers to stop if it is safe to do so, and others allowing drivers to go through the intersection if safe to do so.

  • A flashing amber indication is a warning signal. In the United Kingdom, a flashing amber light is used only at pelican crossings, in place of the combined red–amber signal, and indicates that drivers may pass if no pedestrians are on the crossing.

  • The red signal prohibits any traffic from proceeding.

  • A flashing red indication is treated as a stop sign.

In some countries traffic signals will go into a flashing mode if the Conflict Monitor detects a problem, such as a fault that tries to display green lights to conflicting traffic. The signal may display flashing yellow to the main road and flashing red to the side road, or flashing red in all directions. Flashing operation can also be used during times of day when traffic is light, such as late at night.[6]


Feedback
Your comments are always our motivation!
Home | About us | Products | News | Product knowledge | Contact us | Project Case | Exhibition | Mobile | XML
Copyright © Zhongshan Epistar Electronic Lighting Co.,Ltd