Imagine navigating through a bustling city without the guiding rhythm of traffic lights – it’s almost impossible. Yet, behind those red, yellow, and green signals is a fascinating history of innovation that has shaped the way we navigate our streets. From their early beginnings to the advanced systems we see today, these devices have become essential for keeping drivers, cyclists, and pedestrians safe, ensuring smooth movement through even the busiest of crossings.
One great choice for modern road management is an energy-efficient traffic light. Unlike traditional incandescent bulbs, a light with LEDs uses significantly less power, making it an eco-friendly option that can help reduce energy consumption across cities. LEDs produce a sharp, clear light that’s highly visible in all weather conditions, whether it’s sunny, rainy, or foggy. This increased visibility improves road safety by ensuring that signals are clear to both drivers and pedestrians at all times.
History of Traffic Lights
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Have you ever wondered why red means “stop” and green means “go” at a traffic light? The origins of these colour choices go back to the early 19th century, when British railroads adopted a signal system using red for danger, white for safety, and green for caution.
Unfortunately, an accident involving a white light caused a serious rail collision, leading to changes. Red, which has the longest wavelength and can penetrate fog or dust, became the ideal choice for danger because it is the most visible in tough conditions. Meanwhile, green, with its calming effect, was selected to signal safe passage.
By the 1860s, London officials started using colour-coded semaphores to control the growing number of horse-drawn carriages, adapting the railway system for street traffic. It wasn’t until 1920 that American police officer William Potts developed the first lights in Detroit, though these early systems were still manually operated.
Over the years, these devices have become more advanced, with timers, sound sensors, and even detection systems that adjust to the number of cars at an intersection. Today, the modern traffic light is powered by energy-efficient LEDs, enhancing safety and visibility while using far less electricity.
How do Traffic Lights Operate?
In some areas, semaphores can be modified to prioritise emergency vehicles like fire trucks, ambulances, and police cars. These systems typically use small transmitters that emit radio waves, infrared signals, or strobe lights, which are picked up by sensors mounted on or near the LED traffic lights. There are also systems that rely on audio detection, where a specific siren sound triggers the preemption process.
When an emergency vehicle activates the system, the normal light sequence is temporarily overridden. All lights at the intersection turn red, except for the one in the direction of the emergency vehicle. Sometimes, they use an additional signal to let the approaching emergency vehicle know that the preemption is in effect and to alert other drivers about the incoming emergency.
Traffic Lights Controllers
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Traffic lights in Australia are managed by controllers housed in dedicated cabinets, which play a crucial role in regulating the flow of traffic. While some older systems still use electro-mechanical controllers, most modern signals rely on solid-state controllers. These are more reliable and efficient, incorporating a range of components like power panels, detector interfaces, and conflict monitor units.
A solid-state controller features a conflict monitor unit (CMU) that ensures the signals are safe and don’t display conflicting directions. For example, if the controller were to mistakenly show green for both northbound and eastbound traffic at an intersection, the CMU would detect this error and switch all lights to red, causing them to flash and alerting drivers to stop. However, these monitors can sometimes be triggered by power surges during thunderstorms, leading to false alarms.
In the late 1990s, efforts to standardise traffic controllers led to the development of the advanced transportation controller (ATC) standard. This initiative aimed to create a unified protocol, ensuring better communication and integration between traffic management systems. This standard utilises modern communication protocols to enhance the efficiency and coordination of traffic signals.
Can I Drive Through an Amber Light?
When you see the traffic lights turn amber, it often sparks a familiar internal debate: should you slow down or keep going? It’s a common scenario that many drivers face, and the decision largely depends on your distance from the stop line.
The general rule is to slow down and stop before the stop line when the light turns amber. However, if you’re too close to the intersection to stop safely, it’s better to continue through cautiously. Sudden braking could lead to rear-end collisions, especially if the driver behind you isn’t prepared. Therefore, if you’re too close to stop safely, it’s wise to maintain your speed while keeping a vigilant eye on surrounding traffic as you pass through.
Traffic lights are timed to give drivers enough time to stop safely, and the duration of the amber light is typically based on the speed limit and the road’s grade. For instance, on flat roads, it usually stays on for about four seconds if you’re traveling at 40, 50, or 60 km/h. This time can extend slightly for higher speeds to ensure drivers have enough time to react.
However, failing to stop when it’s safe to do so can lead to significant penalties. According to the Road Rules 2014, not stopping at an amber light can result in a fine and demerit points. In school zones, these fines and points are higher. Moreover, running an amber light increases your risk of being caught by red-light cameras, which can trigger a hefty fine and additional demerit points. Speeding to avoid these cameras can also get you caught by speed cameras.