Traffic Signals / Traffic Lights

Traffic signals refer to statutory traffic control facilities installed at junctions, pedestrian crossings, and designated road sections in accordance with the "Road Traffic Safety Law of the People's Republic of China" and relevant national standards. They regulate the movement, stopping, and turning of vehicles and pedestrians via prescribed coloured light signals, serving as the primary physical tool in modern automated urban traffic management to maintain junction order and minimise collision risks at traffic conflict points.

Core Attributes and Control Logic

Spatial-temporal separation and dynamic allocation of right-of-way: The fundamental function of traffic lights is to resolve junction conflicts in road space through "alternating time segregation". By systematically assigning designated time windows to traffic flows from different directions and streams, it fundamentally eliminates severe, high-casualty crashes caused by "rushing the junction" at unsignalised junctions. 

Statutory mandatory binding force: The red, amber, and green signals displayed by traffic lights carry absolute legal authority. All motorists, motorcyclists, cyclists, and pedestrians must unconditionally adhere to traffic light directions (except when overriding on-site police manual control applies). Flouting traffic signals constitutes a serious traffic offence. 

Standard Signal Interpretation and Right-of-Way Rules

A standard traffic light system comprises red, green, and amber lights, as well as directional arrow lights, each carrying strict legal compliance:

Module 1: General Rules for Circular Signals

Green light (Proceed signal): Permits road users to proceed, provided turning vehicles do not obstruct through-traffic or pedestrians who have been given right-of-way.

Red light (Stop signal): Entry is strictly prohibited. At junctions without dedicated right-turn arrow lights, vehicles turning right may proceed only if it is safe to do so without obstructing oncoming through-traffic or pedestrians (unless a specific red-light right-turn ban is explicitly signed).

Amber light (Warning and clearance signal): When the amber light is illuminated, vehicles that have already crossed the stop line may proceed; vehicles behind the stop line must not attempt to rush through. The amber phase essentially acts as a junction clearance interval, alerting drivers to an impending signal change.

Module 2: Exclusive Right-of-Way for Directional Arrow Signals

Content: Directional arrow lights display arrow graphics to precisely govern specific movements (left turn, straight, right turn). A green arrow permits movement in the indicated direction, while a red arrow strictly prohibits entry in that direction. At junctions equipped with arrow lights, drivers must strictly follow the arrow indications; general right-turn allowances under circular green lights no longer automatically apply.

Special Signal States and Safe Operating Procedures

Beyond standard light sequencing, specific statutory guidelines apply during off-peak hours or system malfunctions:

Procedure 1: Flashing Amber Lights and Handling Traffic Signal Failures 

Flashing amber light (Proceed with caution):

When a traffic light flashes amber continuously, the junction is operating in late-night low-traffic mode or under a temporary hazard-warning state. Road users may proceed with caution, provided vehicles on secondary roads give way to main-road traffic, and turning vehicles give way to straight-moving vehicles. 

Traffic lights completely unlit or malfunctioning (Unsignalised junction protocol):

If traffic lights are completely unlit due to a power outage or system failure, the junction automatically reverts to unsignalised status. Drivers approaching the junction must slow down and strictly observe statutory give-way rules: "secondary roads give way to main roads, give way to traffic from the right, and turning traffic gives way to through-traffic", coming to a complete stop to check that it is clear before proceeding if necessary. 

Procedure 2: Determining Red-Light Offences and Defensive Driving Measures

The "three-photo" conclusive evidence captured by automated enforcement cameras: 

Automated enforcement cameras capturing red-light violations must secure three critical photographic captures: the vehicle crossing the stop line, the vehicle entering the centre of the junction, and the vehicle crossing the opposite stop line. An offence is legally established as "beating the red light" only when all three images form an unbroken sequence. 

Defensive deceleration protocol when approaching junctions:

When approaching a junction as the green light nears its end (about to turn amber), drivers must never accelerate to "beat the amber" or run the red light. The correct defensive driving practice is to assess junction conditions early: proceed smoothly only if too close to stop safely; otherwise, lift off the accelerator and apply progressive braking to bring the vehicle to a controlled halt, eliminating the risk of catastrophic T-bone collisions caused by rushing the lights.