Applicable Countermeasures

Merge and Weave Area Redesign

Merge areas that affect bicyclists are typically associated with intersections. Generally the pavement markings are for lane separation, for indicating an assigned path or correct position for the bicyclist, and for information about upcoming turning and crossing maneuvers. The Manual of Uniform Traffic Control Devices (MUTCD) is the national standard for all pavement markings (as well as signs and signals).4

Pavement markings, such as bike pockets adjacent to left- or right-turn motor vehicle traffic lanes, can be used to make bicycling safer. Double left- and right-turn lanes are particularly difficult for bicyclists. Long merge areas or high speed merges for motorist left turns are also problems for bicyclists needing to make left turns. Local geometric design tailoring may be needed on streets with these characteristics that also have a considerable number of bicyclists in the traffic stream.

In addition to intersection problems, bicyclists often ride on arterials or urban parkways which may contain some freeway-style designs such as merge lanes and exit ramps. If there is bicycle traffic on these roadways then it is likely that a bike lane or paved shoulder will be available. The 1995 Oregon Bicycle and Pedestrian Plan has a good description of the problems that can occur and potential solutions, and the description below is adapted from the plan.5

For the merge lane or entrance lane situation, several problems exist:

  • The angle of approach creates visibility problems.
  • Motor vehicles are accelerating to merge with traffic on the main road.
  • Motor vehicles are typically traveling much faster than bicycles.

The Oregon DOT offers the first design shown at right as one alternative to the entrance lane problem.5

This design creates a short distance across the ramp for the bicyclist at nearly a right angle for improved sight distance, as well as providing a crossing in a location before drivers’ attention is focused on the upcoming merge with motor vehicles.

Similar problems exist for the exit lane situation:

  • Motor vehicles are often exiting at high speeds.
  • The exit angle creates visibility problems.
  • Exiting drivers may not use their turn signal to indicate their desired movement.

The Oregon DOT offers the second design shown at right as one alternative to the exit lane problem.


  • Provide for safer merging of bicycles with motor vehicle traffic.
  • Improve sight distance and awareness for bicycles and motor vehicles involved in potential conflicts at entry and exit ramps.

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  • Where entry and exit ramp revisions are to be considered, the road or street should be evaluated to determine if appropriate for this facility.
  • Determine if other sight distance improvements need to be made.
  • Try to avoid double left- and double right-turn situations for bicyclists.

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Estimated Cost

Construction costs for reconstructing a tighter turning radius are approximately $2,000 to $20,000 per corner, depending on site conditions (e.g., drainage and utilities may need to be relocated). Costs for reconstructing entrance and exit lanes on arterials or urban parkways are also dependent on site conditions.

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Case Studies

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