Curb Extension
ELM-CBE-02 Curb Extension
Working assessment: this pattern’s status reflects a preliminary Commonway System judgment call, pending final review.
#Why this pattern exists
Narrowing the effective roadway width at a specific point shortens pedestrian crossing distance, slows turning and through vehicles, and can reclaim space for other uses (a bus stop, plantings, a parklet), addressing several distinct problems (crossing safety, traffic calming, space reclamation) with one flexible physical treatment.
#Key considerations
- Form should match purpose: a bus bulb needs a different length and clearance than a corner pinchpoint or a mid-block chicane
- Drainage design at the extension point needs attention, since it interrupts the normal curb and gutter line
- Sightlines for both drivers and pedestrians should be checked at the extension, especially near a crossing, since the extension changes sightline geometry
#Related patterns
Curb (ELM-CRB-01), Crosswalk (ELM-CRW-08) (typical pairing at a crossing); Plaza/Parklet (FAC-PLZ-07) (Facility pattern this often anchors); Transit Boarding Island (ELM-TBI-41) (a related but distinct treatment for transit stops)
Unsourced claim
Formal citations for this pattern have not yet been compiled from primary sources.