PROGRAMS AND SERVICES
TRAFFIC CALMING PROGRAM
Level 3 Traffic Calming: BULB-OUTS

Bulb-outs narrow the roadway width at an intersection by modifying the curb return providing a physical constraint at an intersection which forces motorists to "slow down" in order to pass through the narrower roadway section. This measure is typically constructed at intersections, but mid-block locations may be considered.

This type of measure introduces two traffic calming concepts: physical constraints and visual traffic calming. Level 3 traffic calming involves physical constraints which produces a point speed reduction and pedestrian-friendly crossings. Point speed reductions may occur at bulb-outs, but motorist speed beyond the bulb-outs are typically either unaffected or higher than before installation. Visual traffic calming involves installing features which provide visual breaks along long sections of roadway to make the roadway appear either shorter or as a not a through route.

Bulb-outs offer several benefits to a neighborhood. These include the following:

• Visual traffic calming effect and possible point speed reduction
• Highlights intersections for motorists
• Reduces length of crossings for pedestrians
• Provides opportunities for landscaping
• No adverse effect on emergency vehicle access

There are some design obstacles and with bulb-outs. These include the following:

• Storm drain, street lighting, sewer, and other utilities may be affected and require relocation
• Reduces available on-street parking spaces
• Forces bicyclists into the travel lane with motorized vehicles

IMPLEMENTATION

Beneficial on long, straight, and flat roadway sections where visual traffic calming effects apply. Due to pedestrian benefits, consideration should be given to high pedestrian use intersections (adjacent to schools, commercial centers, etc.). Design considerations include accommodating large vehicles (fire trucks, garbage trucks, moving vans, etc.), street lighting, maintaining drainage system, allowing bicycle access, and landscaping and the associated maintenance and sight distance issue