Study on the risks of dooring alongside parking vehicles

Cycle Competence member Rosinak & Partner has just finished a comprehensive study on cycling alongside parking vehicles and the risks associated with it. The study was commissioned by the Austrian Road Safety Board (KFV). All over Austria ten locations were researched via video analysis. Further, cyclists and car drivers were interviewed. The results show the risk potential for cyclists:

On average over all ten locations three quarters of all filmed cyclists were moving within the dooring zone (75 cm width). This means they are at risk of getting hit by suddenly opening car doors. Additionally, 80% of the time car drivers do not keep the necessary safety distance to cyclists when overtaking. Three quarters of the interviewed cyclists have already been in an accident or in a critical situation involving car doors being opened.

(Narrow) multi-purpose bike-lanes endanger cyclists

The video analysis showed that cyclists rely heavily on longitudinalmarkings (lane marking etc) for orientation. Pictograms also influence the choice of positioning. Longitudinal markings result in a division of the road into zones with the following effects: cyclists ride in the middle of “their lane” where they are in danger of being hit by carelessly opened car doors (“Dooring”). At the same time the lines suggest to drivers that there is sufficient room for safe overtaking. This means they are overtaking with too little distance. At a minimum width of the multi-purpose bike lanes according to the guidelines and decrees for roads (RVS) of 1.5m cyclists have to move within the door zone. The standard width of 1.75m according to RVS is just enough to allow cyclists to ride outside the dooring zone.

Dilemma for cycle traffic planning

The interviews made a dilemma for cycle traffic planning visible: cyclists feel safer with cycling lanes being marked than without the paint. However, they are pushed towards the parked cars by the narrow multi-purpose bike lanes. The markings also suggest to car drivers that they have “their own lane” and therefore enough space for overtaking. This explains the contradiction of 80% of drivers not keeping the necessary safety distance when overtaking but the majority of drivers saying they only overtake cyclists when there is enough space.

Necessary lane widths for keeping the safety distance

Keeping the necessary safety distance when overtaking makes very wide lanes necessary. The theoretical considerations in the following diagram show a one-way road with parallel parking on both sides would need a width of at least 5.8m. But one-way roads of that width are not practicable.


Recommendations from the study:

  • Increase measures to raise awareness and inform about traffic: raise awareness among drivers and cyclists how cyclists are at risk when car doors are opened; and promote opening car doors with the right hand (“The Dutch Way”)
  • Raise awareness on keeping sufficient safety distance when overtaking cyclists
  • Check whether 1.75m instead of 1.5m minimum width for multi-purpose bike lanes is possible
  • Markings (cycling pictograms including arrows, e.g. Sharrows) significantly influence where cyclists choose to ride. They are orienting themselves according to the pictograms. Therefore these should be placed in a way as not to direct cyclists into the dangerous area into which open car doors can reach (Dooring Zone).
  • Develop clear criteria and standards for the use of Sharrow road markings
  • Where possible mark safety areas/distance zones from parking cars.

typ_2_gv typ_1_gv

Sharrow road markings without and with marked distance zones from parking cars.

The presentation of the study results at the KFV cycling expert workshop can be downloaded as PDF here.

Posted on June 29, 2017