traffic light
Let an agent handle traffic lights by type, signal meaning, timing, accessibility and faults, with road rules by country.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent handle traffic lights by type, signal meaning, timing, accessibility and faults, with road rules by country.
A signalling device at road intersections, pedestrian crossings and other locations that controls traffic with coloured lights, usually red, amber and green, and pedestrian signals.
What it is for: Controlling conflicting traffic flows safely.
It can be obey signals; report faults to the road authority; plan signal timing; provide accessible pedestrian signals.
Distinguishing features
Controls traffic by coloured lights
Fixed-time or adaptive
Signal meanings vary by country
Accessible signals help blind pedestrians
What it looks like
Poles or gantries with red, amber and green lamps and pedestrian figures.
How it is recognised
Red, amber, green lamps
Arrow and pedestrian signals
Temporary portable lights at roadworks
Related models
is a kind of - category
controls - use
is installed at - place
is governed by - rules
In practice
Families and kinds
fixed-time signals
actuated and adaptive signals
pedestrian and cycle signals
temporary traffic lights
flashing warning signals
Standards and regulation
Vienna Convention on Road Signs and Signals
EN 12368 traffic control equipment
National traffic signal manuals such as MUTCD
Failure modes and hazards
Signal failures at busy junctions
Running red lights
Short pedestrian crossing times
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.traffic-light
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Meaning What signals mean.
Meanings vary by country.
Colours
Red, amber, green.
Colours
Signal meaning.
- What does each signal mean in this country? provenance
- Is right turn on red allowed? boundary
Arrows
Filters.
Arrows
Arrow signals.
- What do arrow signals permit? definition
- Do pedestrians have priority? boundary
Operation Timing.
Timing affects safety.
Timing
Cycles.
Timing
Timing.
- Is the signal fixed-time or adaptive? definition
- What is the cycle length? measurement
Pedestrians
Crossing time.
Pedestrians
Pedestrian timing.
- Is crossing time long enough for slower pedestrians? boundary
- Which standard walking speed is assumed? measurement
Accessibility Inclusive signals.
Signals should be accessible.
Audible and tactile
Signals for blind people.
Audible
Accessible signals.
- Does the crossing have audible or tactile signals? definition
- How can they be requested? action
Colour vision
Position cues.
Colour
Colour vision.
- Can people with colour vision deficiency read the signal by position? boundary
- Is the layout standard? provenance
Faults Failures.
Failures need rules.
Failure
What to do.
Failure
Signal failure.
- What are the rules when lights are out? provenance
- How should drivers proceed? action
Reporting
Road authority.
Reporting
Fault reporting.
- How can a fault be reported? action
- To which authority? provenance
What the second pass must settle
- Should signal types be separate entries?
- How should country rules be linked?
- How should fault reporting be localised?