Assessment of Bicycle Lane Separators (TG)

ViaStrada is carrying out research on bicycle lane separators for VicRoads.  Glen Koorey (University of Canterbury) reported on the research at the 2013 Transportation Conference in Dunedin. The research was carried out in two locations. The conclusions, as stated in the conference paper, as as follows:

In this paper, the effects of implementing narrow separators on existing cycle lanes on road user behaviour, especially motorists, were assessed.

  • On the Strickland Street intersection approach, many encroachments occurred at the observed area during the full traffic signal sequence prior to the separator implementation. The implementation of several Riley separators near the cyclist waiting area led to a decrease in encroachments, especially during the red signal phase. Although the behaviour change was statistically significant, the total number of encroaching vehicles was still rated as too high and, therefore, three flexible vertical posts were installed between the last separators to increase the separation between motor vehicles and cyclists. This treatment virtually eliminated the encroachment of motor vehicles during the green signal phase, although several approaching drivers still entered the cycle lane during the red signal phase before correcting themselves.
  • Although not as prevalent as Strickland St, a reasonable proportion of encroachments were observed on the Kotare Street curve before the separator implementation. The implementation of several Riley separators shifted motor vehicles slightly out of the cycle lane, but there were concerns about their conspicuity and effect on road user behaviour. Therefore, the separation of cyclists and motor vehicles was increased by the installation of a single flexible vertical post between the first two separators. The combination of Riley separators and the post had a very strong effect on road user behaviour and minimised encroachments along the observed road section immensely.

In conclusion, implementing low-profile separators on existing roads has effects on road user behaviour. In the separated area, motor vehicles encroach less into the cycle lane. However, the encroachment reduction is only slight, and could perhaps increase again due to drivers becoming accustomed to crossing the relatively low separators. Therefore, the combination of low-profile separators and vertical posts is a relatively inexpensive way (especially compared with kerb reconstruction) to increase the effectiveness of cycle lane separation.

The vertical posts strongly prevent motor vehicles from encroaching into the cycle lane. The observations on Kotare Street indicate that a single post, in combination with low Riley separators, has a positive effect on the behaviour of motorists. On Strickland Street, implementing multiple flexible posts close to the intersection was necessary to influence motor vehicle behaviour. Too few posts or posts implemented too far from the intersection might be ignored or forgotten by queuing and turning vehicles. The combination of Riley or other low separators and vertical posts is also useful in areas similar to Strickland Street or Kotare Street. From the user surveys (the results are not reported here), most cyclists appreciated the perceived safety provided by the separators, but by themselves, they would not be sufficient to prevent motor vehicle encroachment. The results indicate that the separators combined with posts might be a suitable tool of making cycling more attractive.

Follow the links to download the conference paper and the PowerPoint presentation. The paper was co-authored by Axel Wilke and research assistant Judith Aussendorf.

Where presented/published

2013 Transportation Conference in Dunedin