Applications:
- closures are typically applied only after other measures have failed or been determined
to be inappropriate
- for all types of closures, provisions are available to make diverters passable for
pedestrians and bicyclists
- often used in sets to make travel through neighborhoods more circuitous - typically
staggered internally in a neighborhood, which leaves through movement possible but less
attractive than alternative (external) routes
- closures have been used as a crime prevention tool
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| Descriptions: |
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Diagonal diverters are barriers placed diagonally
across an intersection, blocking through movement; they are sometimes called full
diverters or diagonal road closures
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Half closures are barriers that block travel in one
direction for a short distance on otherwise two-way streets; they are sometimes called
partial closures, entrance barriers, or one-way closures (when two half-closures are
placed across from one another at an intersection, the result is a semi-diverter)
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Full-street closures are barriers placed across a
street to completely close the street to through-traffic, usually leaving only sidewalks
open; they are sometimes called cul-de-sacs or dead-ends
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Median barriers are raised islands in the centerline of
a street and continuing through an intersection that block the left turn movement from all
intersection approaches and the through movement at the cross street
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Design/Installation Issues:
- there may be legal issues associated with closing a public street
- can be placed at an intersection or midblock
- barriers may consist of landscaped islands, walls, gates, side-by-side bollards, or any
other obstruction that leave an opening smaller than the width of a passenger car
Potential Impacts:
- concern over effects on emergency response, street network connectivity and
capacity, and parallel local streets that carry diverted traffic
- may divert significant traffic volumes
- no significant effect on vehicle speeds beyond the closed block
Emergency Response Issues:
- half closures allow a higher degree of emergency vehicle
access than full closures or diagonal diverters
- all three types of closures can be designed to allow emergency vehicle access
Typical Cost:
- costs range between $2,000 for a simple half-closure and $35,000 for
highly-landscaped diagonal diverter
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Washington, DC
20005-3538 USA
Phone: 202-785-0060
Fax: 202-785-0609
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SPEED HUMP | SPEED TABLE | RAISED INTERSECTION | CLOSURE | NEIGHBORHOOD TRAFFIC CIRCLE | CHICANE | CHOKER | CENTER ISLAND NARROWING |
