Sight Distance Improvements:

Realigning skewed or obtuse-angle intersections improves sight angles for intersecting roadways.

Photo by Peter Lagerwey

Photo by Charles Hamlett
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Adequate sight distance is vital for safe bicycling. Bicyclists need to see the movements of motor vehicles, and vice versa. Intersections are often areas where a number of sight distance problems occur. For example, on-street parking of motor vehicles can restrict the view. Trees, shrubbery, and other flora can also impede the line of sight. Improper placement of signs can decrease sight distance. Skewed intersections, where cross streets are greater or less than 90 degrees, can make it difficult to see other vehicles, as well as increase the exposure of bicyclists (or pedestrians) crossing the street. Problems similar to the above also often occur where driveways intersect with streets.

Sight distance problems can also occur away from intersections due to vertical curves. Use of the SHARE THE ROAD sign (see case study #41) would be appropriate on roads or streets with significant bicycle traffic.

Purpose

  • Improve the ability to see other modes of traffic.
  • Increase awareness and safe behaviors by both cyclists and motorists.
  • Increase reaction time.
  • Decrease stopping distance.

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Considerations

  • Determine whether on-street parking is necessary.
  • Determine the most appropriate kind of parking if necessary.
  • Provide appropriate signs at street intersections and problem driveways.
  • Provide the appropriate kinds of trees, shrubbery, and flora.
  • Place street furniture so sight distance is not reduced.
  • Determine if skewed intersections should be realigned.

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Estimated Cost

Costs will vary depending on the treatment. Re-striping may be all that is necessary to eliminate unnecessary parking. The cost of sign removal or relocation is dependent on the size of the signing. The same would also be true for removal of trees, shrubbery, and other flora.

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Case Studies

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