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Purpose of mapping traffic lights
Map stopping lines, not every physical signal head.
Many intersections have multiple traffic light poles for visibility, but we only map the stop line for each direction of travel — not each individual light.
Intersections vary widely, and not every layout can be prescribed. Use pragmatic judgement.
Traffic lights do not affect routing. They exist only to:
- Provide drivers with a visual reference
- Enable enhanced (“decorated”) turn instructions
If unsure, apply the 80/20 rule (Pareto Principle):
Focus on the 20% of effort that delivers 80% of the value.
In practice, map the clear, primary stopping points that most drivers use.
Avoid over-engineering rare, complex, or edge-case signal setups that add minimal benefit.
Keep it simple and prioritise what meaningfully improves the driver experience.
Traffic lights may be mapped when all the following circumstances exist:
Traffic lights are fixed and permanent installations
Traffic lights are a three-coloured light system (red, yellow/amber, green)
At junctions with a minimum of three segments (e.g. T-intersections)
At junctions handling regular public road traffic
Traffic lights must operate 24 hours a day.
Traffic lights must not be mapped in any of the following circumstances:
Traffic lights related to roadworks or other temporary installations
Traffic lights used for pedestrian crossings or drawbridges
At junctions that exist only to facilitate crossing bus, tram or rail routes.
Like all permanent hazards, traffic lights must be mapped on public roads, with the exception that they should be mapped where the non-public road (e.g. parking or private segments) reconnect to the public road network.
Traffic lights and slip/turn lanes
The traffic light feature has built-in detection for slip/turn lanes as discussed in the staff how-to document. The detection is based on heuristics and doesn’t always get it right. After mapping traffic lights, editors should check at-grade connections/slip/turn lanes/previous turns and crossing paths/future turns appear correctly by clicking on the traffic light. If the turns are missing, a junction box or path should be mapped (whichever is most appropriate).
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Understanding slip/turn lane heuristics
A screenshot of the detection methods are placed here for convenience, with more detail available in the staff produced how-to document.
Method A: Path-Based Detection (Explicit)
Method B: Automatic Discovery (Heuristic)
Practical examples demonstrating these heuristics working and not working are shown below under " Understanding previous turn detection".
Configuring traffic lights
In Australia, the preferred configuration for traffic light visibility and voice instructions is to use the default settings, except where discussed below. Waze controls the default settings to ensure they’re optimal for the majority of use cases. In overly complex or unusual intersections, optimising settings may be required, though this should occur rarely.
Australia does not use the serial number feature, so leave this box blank.
After traffic light decoration
Waze will automatically give an “after the traffic lights” instruction for a turn 100m or less beyond the traffic light.
However there are times where it may be helpful to override the Waze defaults. In this example, there is a keep left turn that is physically made after you proceed through the traffic lights central zone. This is a valid spot where “after the traffic light” decoration setting adjustment will assist the driver.
Traffic lights on H, hash (#) and unconventional junctions
Heuristics used in lane guidance to detect H-style and hash (#) intersections are also used in traffic lights. Similarly, when a H or # junction is skewed, heuristics may not detect the intersection as a H or # junction, which will cause voice instructions to announce to drivers “after the traffic lights” instead of “at the traffic lights”. In these scenarios, a junction box or path (whichever is more appropriate), should be mapped so the traffic lights can detect all components of the skewed H, # or unconventional intersection.
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Below is an example where WME Lane Tools script shows a purple colour, indicating a negative heuristic detection, and drivers were receiving an “after the traffic light” instruction.
A path was added on the red arrow route shown in the above image, causing the path to display under the traffic light’s “crossing paths”, and drivers then received the correct traffic light instruction thereafter.
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Examples of when to map traffic lights
This intersection is suitable for a traffic light to be mapped as it meets all the mapping criteria. As there are no stop lines in the middle of the intersection, the traffic light is only mapped on the entering segments
This intersection is suitable for traffic lights to be mapped as it meets all the mapping criteria. Additionally, as the intersection is elongated with stop lines within the median, traffic lights are mapped on the middle segments
While these traffic lights are not on public roads, they are reconnecting to the public road network and also meets all the mapping criteria. These are both suitable locations for mapping
Examples of when not to map traffic lights
Although it is a three-coloured light system, it is temporary, related to roadworks and it is not at a junction with three segments. This is not suitable for mapping
Although the traffic light is a fixed and permanent installation, operates 24 hours a day and at a junction with a minimum of three segments, it exists only to allow buses/rail to cross the road. This is not suitable for mapping
This is a two-coloured light system for a tunnel entry which does not operate 24 hours a day and would only be activated manually. This is not suitable for mapping
Understanding previous turn detection
This section looks at some cases where “previous turns” may or may not appear belonging to a traffic light and explains why.
Traffic light with previous ramp
Uses Method B: Automatic Discovery (Heuristic) to detect this slip lane. The blue route is captured as a “previous ramp” because the red dashed arrow is between 30-50m in length. The default Waze behaviour for “previous ramp” will show a traffic light on the map but will not play a traffic light voice instruction.
This should not be overridden for consistency reasons, except in overly complex or unusual intersections.
Traffic light with no previous ramp - segment length
Failed previous ramp detection with “Method A: Path-Based Detection (Explicit)” - this is expected behaviour and does not need to be fixed. The segment with the red dashed arrow is >50m in length. As such, the “previous ramp” is not captured and Waze will not display a traffic light or play a traffic light voice instruction.
Traffic light with no previous ramp - segment angle
Failed previous ramp detection with “Method B: Automatic Discovery (Heuristic)” - this is expected behaviour. For a previous turn to be detected, segments A and B need to be nearly straight, with the angle delta between 0-10 degrees. In the above example, no previous turn is detected belonging to this traffic light because the segment A to B angle delta is > 13 degrees.