Design and Build Cycle-friendly traffic calming

  1. Plan
  2. Design and Build
  3. Sell
  4. Evaluate

In this section, we focus on traffic calming measures to apply on sections of cycle highways in mixed traffic. This means that:

  • bicycles and cars share the same carriageway;
  • the route is an important connection for cyclists.

In many cases, simply removing the through traffic of cars by filtering permeability allows the cyclists to safely share the road. If there is already a significant amount of bicycle traffic, the road can become a bicycle street by predominant use. But sometimes additional measures need to be applied to ensure that the speed of different groups of users is as uniform as possible.

The traffic calming measures

  • Should not be an obstacle for cycling; should not decrease comfort because of uneven surfaces, vibrations, the need to stop or other interruptions.
  • Should not create a risk to the cyclist of losing their balance and falling, also in poor visibility or adverse weather conditions. Bicycles are more endangered than cars by unevenness, local slopes, etc.  
  • Should not result in cyclists behaving unpredictably, e.g. changing their position on the carriageway to avoid an obstacle.

Best practice

Some speed humps and tables are called sinusoidal, because of the shape of the cross-section of the ramp (instead of e.g. trapezoid or half-circle). To be more specific, the ramp up follows e.g. the cosine function between -π and 0, the ramp down – from 0 to π.

The advantage of the shape is a smooth, continuous transition between the carriageway, ramp and top of the hump or table. Lack of angles is appreciated both by cyclists (no impact on body transferred by handlebar or seat post) and car-drivers (no damage to the vehicle suspension). It also makes winter maintenance easier.

Tips & tricks:

  • Prefab concrete ramps are more resistant to deformations than ramps constructed on site e.g. from small blocks.
  • The proportion between height and length of the ramp can vary, depending on the speed limit and whether the street also has to accommodate public transport busses.
  • On raised crossings different steepness can be applied on different exits, if e.g. one of the streets has priority or includes bus traffic.

Mistakes to avoid

In mixed traffic:

  • Uneven surfaces, e.g. sections of cobblestones, cause discomfort and vibrations, can be slippery when wet;
  • Speed humps not covering the whole width of the carriageway can result in cyclist weaving unpredictably and can disrupt the flow of cyclists riding in pairs or groups;
  • Local changes in the width of the carriageway (chicanes, narrowings) can lead to conflicts in/before bottleneck locations.

Traffic calming measures in other situations

A wider catalogue of measures for traffic calming is suitable where there is space for separate cycle lanes or paths that allow the cyclists to bypass the measures.

Measures applied on streets perpendicular to the cycle highway are discussed in the section on non-signalised crossings.

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