Provide an adapted road layout

That's how you do it

Optimizing the flow of car traffic and the dimensioning of roads have a positive effect on air quality. Shielding car traffic from residents and other road users limits exposure to poor air quality.

When constructing or redesigning roads, it is best to try to keep the impact on air quality as limited as possible. This can be done in 3 ways:

• Make sure that you can drive at a constant speed. Avoid frequent braking and acceleration.
• Avoid street canyons by custom sizing the road
• Limit exposure to air pollution by shielding car traffic from other road users and residents.

Tips

• Promoting throughput can be done in the following ways, among others:
  • construction of roundabouts
  • construction of exit lanes at intersections
  • axle shifts as traffic inhibitors instead of speed bumps
• Dimensioning of the roads:
  • determine the distance from the road axis to the buildings in function of the height of the buildings in order to avoid street canyons
  • Provide sufficient distance between car traffic and the bicycle path and/or sidewalk
• Limiting exposure by, among other things:
  • creating buffers (green buffers, screens)
  • covering and tunneling the road

Knowing more

Street canyons are narrow streets with high buildings. In these streets, the exhaust gases are diluted worse and air pollution can accumulate. This occurs as soon as the width of the street is less than 3 times the height of the adjacent buildings, but is more pronounced as soon as the width of the street is less than 1.5 times the height of the adjacent buildings. For example, if the buildings are 9 m high, the street canyon effect already occurs as soon as the street width is less than 27 m, but the effect increases quickly as soon as the street is narrower than 13.5 m.

More information

• Report with guidelines on environmentally friendly road design (Department of Environment, Flanders)
• Report 'Creating healthy living environments: focus on air quality (Department of Environment, Flanders)