Vertical Speed Control
ELM-VSC-06 Vertical Speed Control
Working assessment: this pattern’s status reflects a preliminary Commonway System judgment call, pending final review.
#Why this pattern exists
Signage and paint alone rarely change driver speed on their own; a physical vertical deflection imposes a real cost on speeding that self-enforces without requiring active enforcement presence. This pattern exists to document the distinct forms this treatment takes and where each is appropriate, since a hump, table, and cushion serve different vehicle types and roadway contexts differently.
#Key considerations
- Form should match context: cushions allow emergency vehicles and buses to straddle them with less impact than a full-width hump or table
- Placement and spacing should be based on desired speed and roadway geometry, not applied as a one-size-fits-all interval
- Drainage and snowplow operations need consideration in colder climates, since a raised feature can interfere with both
#Related patterns
Rumble Strip (ELM-RMS-07) (a related but distinct calming treatment using texture rather than vertical deflection); relevant Local and Collector Segment patterns where speed control applies
Unsourced claim
Formal citations for this pattern have not yet been compiled from primary sources.