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CENTER ISLAND NARROWING
Often used with a marked crosswalk
Raised islands are installed along the center of the street to effectively narrow the travel lanes in each direction. They can be landscaped to improve the aesthetics of the location and can have a built in pedestrian refuge when placed in conjunction with a mid-block crosswalk.
Parking may need to be removed along the affected roadway section. Bicycle users may feel more vulnerable on narrower lanes
They may also be called mid-block medians, median slow points, or median chokers.
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Temporary Installation
San Marino, CA |
Permanent Installation
Baldwin Park. CA |
PROS
1. Results in reduction in speeds
2. Enhances pedestrian environment.
3. Helps safety when used on curved roads by reducing speed.
4. Can be evaluated on temporary basis first.
5. Can be landscaped.
6. Can be a "Gateway" feature.
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CONS
1. May result in loss of on-street parking.
2. Moderately expensive measure if landscaped.
3. Center islands may be hit at night unless well marked.
4. Reduced lane widths not favored by bicycle users.
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Summary of Effectiveness
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Volume Reduction
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No
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Speed Reduction
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Yes (Slight)
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Safety Improvement
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Unknown
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-
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-
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Streets to Use On Collector, Local
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Local/Collector
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Use on Bus Route
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Yes
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Use with Curbs and Gutters
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Yes
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Spot or Area-wide Use
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Spot
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-
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-
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Emergency Service Access Issues
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No
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Impacts on Arterials
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No
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Change in % Trucks
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Unknown
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Environmental Changes
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No
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-
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-
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Dependence on Enforcement
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No
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Level of Violation
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N/A
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-
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-
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Aesthetics and Landscaping
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Limited
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