Speed Humps, Raised Crossings, and Similar Raised Areas

Purpose sh1.png

Reduce vehicle speeds, increase driver yielding, and improve bicyclist and pedestrian crossing safety.

Description

A family of vertical traffic calming devices that involve raising the height of the pavement for a short section to slow vehicle traffic and improve safety conditions. Variations include:

  • Speed humps/tables are raised pavement area with a flat top to limit disturbances to larger vehicles such as emergency response or transit vehicles. Large yield triangles are marked on the sloped areas to provide a visual warning for users.
  • Raised crossings are designed in a similar manner to speed humps/tables but provide a crossing along wider flat tops. The crossings can be either at sidewalk level or modified to be 3 to 5 inches high to address drainage challenges.
  • Speed cushions have wheel cutouts to allow large vehicles such as buses or emergency vehicles to pass through unaffected. Unlike speed humps, speed cushions can’t be used in combination with crosswalks.

Safety Benefits

  • May reduce vehicle speeds and improve driver yielding to crossing pedestrians.
  • Raised crossings increase the height of pedestrians in driver’s field of vision.
  • Raised crossings may provide a continuous travel path for pedestrians with disabilities. Detectable warning surfaces (e.g., truncated domes) must always be implemented at pedestrian crossings, per ADA standards, to provide access for people with vision disabilities.
  • May reduce the frequency and severity of crashes for all road users.

View locations where this tool is installed in Arlington County

Street Types and Context

Applicable Street Types

All local streets.

Other Location Guidance 

  • Vertical traffic control measures such as speed humps, tables, and cushions are best used on streets with lower vehicle speeds (25 mph and under) and volumes where traffic calming is needed, such as near pedestrian and bicycle activity generators (i.e., schools, parks, trail crossings).

Primary User Groups

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Key Implementation Considerations

  • Consider priority and delay of emergency response vehicles, buses, or heavy vehicles.
  • Certain designs require modifications to existing drainage.
  • Investigate feasibility of other traffic calming measures first.

Expected Crash Reduction

For raised crossings:

  • 45% for pedestrian crashes (Elvik et al. 2004).
  • 51% for bicycle- vehicle crashes on entrances or exits to streets and driveways (Schepers et al. 2011).

A definitive crash reduction estimate has not been established for speed humps/tables/cushions. Research suggests speed humps, tables, and cushions reduce crash severity (Elvik and Vaa, 2004).

Cost

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Costs are typically in the moderate range

Timeline

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Less than one to three years depending on complexity and engagement. Raised crossings implemented with changes to drainage may take longer.

References

 

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