Hardened Centerlines and Turn Wedges

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Reduce vehicle turning speed and increase vehicle yielding to pedestrians.

Description

Hardened centerlines are flexible delineator posts or raised speed humps placed along the yellow centerline at an intersection to block the diagonal path through the intersection and encourage drivers to turn left at a slower speed.

Turn wedges are raised humps or flexible delineator posts and pavement markings wedged between the sides of perpendicular crosswalks at an intersection to reduce turning speeds and encourage driver yielding.

Safety Benefits

  • Slows left-turning vehicles without reducing traffic capacity.
  • Guides vehicles to wider turning angle for safer and more predictable turns.
  • Increases visibility of pedestrians in crosswalk to turning drivers.

View locations where this tool is installed in Arlington County

Street Types and Context

Applicable Street Types

Principal and Minor Arterials in Urban and Urban Core contexts. Local Principal and Local Minor streets in all contexts.

Other Location Guidance

  • Hardened centerlines can be installed at intersections or midblock crossing locations.
  • In areas with turn-related crash histories or observed improper yield behaviors.
  • Turn wedges can be installed at the corners of an intersection.

Primary User Groups

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Key Implementation Considerations

The turning paths of the design vehicle must be considered.

  • Can be constructed rapidly and inexpensively using markings and flexible delineators.
  • The turning radius of trucks and buses should be considered when installing turn wedges.
  • Roadway maintenance activities like snow removal and street sweeping must also be considered when designing in-street infrastructure.

Expected Crash Reduction

46% for all crashes at raised medians (Bahar et al. 2007).

A crash reduction estimate has not been established for turn wedges, but slower vehicle turning speeds are expected.

Cost

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Typically, a lower cost treatment.

Timeline

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Typically, a quick-build treatment

References

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