Road User Behaviour on One-way Cycle Tracks of Different Widths

Poul Greibe, Thomas S. Buch, Paper from 4th International Cycling Safety Conference, September 2015

ABSTRACT

The main objective of this study is to examine how widths of cycle tracks influence the behaviour, flow and capacity of bicycle traffic, factors which also affect traffic safety.

Empirical data has been collected by video observations at 8 different cycle tracks of varying widths (1.85 m-2.85 m excl. curb between cycle track and carriageway).

The locations are characterised by high bicycle traffic volumes on the tracks, no traffic lights/junctions/bus stops/zebra crossings nearby, and no dividing verge between cycle track and carriageway. Speed and lateral positions have been measured for 8,925 cyclists.

The average speed is 21.6 km/h but differs slightly between locations. The traffic volume does not affect average speed, but dispersion decreases with increasing bicycle traffic volumes. At narrow cycle tracks, cyclists are riding closer to the sidewalk and closer to each other during overtaking compared to cycle tracks of a larger width. Car parking in the road side next to the cycle track reduces "the effective width" of the cycle track with about 10-15 cm. High bicycle traffic volumes are only observed in short time spans and the capacity limit appears not to be reached. When calculating capacity from short time spans, controlling factors are used, and the hourly capacity of a 2-lane cycle track is estimated to about 3,000 bicycles/h. The width does not affect the capacity much, unless the number of lanes is reduced or increased.

A cargo bike has an average speed of 16.3 km/h and reduces capacity equally to 3-4 regular bicycles. Based on the data, recommended widths of cycle tracks are found in order to ensure a safe and efficient traffic operation for cyclists.