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FORCED TURN ISLANDS, BARRIERS & CHANNELIZATION
Make sure problems do not move elsewhere.
Temporary installation is highly recommended for initial evaluation.
These are traffic islands or curbs specifically designed to prevent traffic from making certain movements at an intersection or to force the traffic into specific patterns. They are sometimes referred to as "Pork Chops" or right-turn islands.
Care should be taken to evaluate the effects of diverted traffic on adjacent streets. Problems could be simply transferred from one location to another.
Access to residences may also be adversely affected so coordination with neighborhoods is important.
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Temporary Installation
Temp Island Installation
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Permanent Installation
Baldwin Park, CA |
PROS
1. Potential to reduce traffic speed.
2. Reduces traffic volumes.
3. Can be used to reduce cut-through traffic.
4. Self-enforcing.
5. Landscaping possible.
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CONS
1. May reduce access for emergency vehicles.
2. Diversion to longer routes may cause inconvenience to and be opposed by affected residents.
3. Care needed if placed on transit routes.
4. May transfer problems elsewhere.
5. Need to allow bicycle access.
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Summary of Effectiveness
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Volume Reduction
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Yes
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Speed Reduction
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Likely
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Safety Improvement
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Possible
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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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Check Routes
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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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Possible
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Impacts on Arterials
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Possible
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Change in % Trucks
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Unknown
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Environmental Changes
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Unknown
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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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Self-Enforced
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-
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-
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Aesthetics and Landscaping
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Possible
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