Traffic Signal
ELM-TFS-14 Traffic Signal
Related Media
The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.
Why this pattern exists
Above a certain volume or conflict complexity, an uncontrolled or sign-controlled intersection can no longer safely and efficiently sort competing movements; a traffic signal imposes timed, positive control over who moves when. This pattern exists to document signal use as a documented departure from Commonway System’s roundabout-default intersection treatment, requiring its own justification.
Key considerations
- Consistent with Commonway System’s intersection defaults, signal installation should require documented burden-of-proof justification rather than being a default choice1
- Timing and phasing should account for all modes present, not just vehicle throughput; pedestrian and bicycle phases need adequate crossing time
- Signal coordination along a corridor affects speed and platooning behavior well beyond the single intersection where it is installed
Related patterns
Roundabout (INT-RAB-01) (the CS default this pattern is a documented departure from); Pedestrian Signal (ELM-PDS-15), Bicycle Signal (ELM-BCS-16) (companion signal types at a signalized intersection)