1. Left-turn provision for cyclists
De Bilt, Blauwkapelseweg, left-turn provision for cyclists. As a safety provision for cyclists turning left, local authorities in De Bilt have constructed a large red-asphalt platform with a traffic island. Cyclists turning left may get into the left-hand lane in time and have room to stop and yield to oncoming traffic.
2. Routes and intensities
Blauwkapelseweg (approx. 12,000 mv/24h in 2003) is used, among others, by rat-run traffic from
towards the A27. Local authorities intend to reduce rat-run traffic, aiming at a maximum of 7,000 mv/24h. A major bicycle route runs at an angle to Blauwkapelseweg. As the side-roads do not face each other directly, cyclists have to perform a bayonet-like manoeuvre: follow Blauwkapelseweg for a short distance and then turn left. Zeist
3. Initial design
The initial design for Blauwkapelseweg featured relatively narrow separate bike paths and pavements. This solution has various drawbacks for cyclists wanting to perform the bayonet-like manoeuvre. They can not get into a left lane in advance, the turns are quite sharp and there is no traffic island halfway along. However, the main reason for local authorities to drop the bike paths were the residents’ objections to the (too) narrow pavements.
4. Second design
In this design the entire bayonet is implemented as a single large red platform with a traffic island. Cyclists can decide for themselves when to get into the left lane and halfway along find room to wait for cars from the opposite direction. The design was provided by consultants Oranjewoud and Goudappel Coffeng.
5. Example left-turning cyclists
In actual practice the opportunity to get into lane early is used quite often by cyclists. Due in part to residential exits the traffic island is partly executed in paint.
6. Pedestrian crossing
In the middle of the platform a pedestrian crossing has been implemented. If so desired, cyclists may also use this facility, wheeling their bike. On the other side of the platform (not visible in this picture) an existing pedestrian traffic light has been maintained. This is used, for instance, by school children crossing to gym class.
7. Bicycle and car
The lane next to the traffic island is wide enough (> 3.5 metres) to accommodate a car and cyclist side by side. When cars have to wait in line (as in this picture due to a left-turning car having to wait for oncoming traffic), cyclists can ride by without any problems.
The picture also shows the pedestrian crossing with traffic lights carried over from the old situation.
8. Bicycle and lorry
The lane is too narrow to accommodate lorries and cyclists side by side. Lorries have to remain behind cyclists and vice versa. This also reduces the risk of blind-angle accidents.
9. Swerve opportunity
As there is no difference in height between platform and pavement cyclists may easily swerve to the pavement. The picture shows a cyclist probably afraid to get into the left lane, preferring to wait on the pavement until convinced it is safe to cross.
Peter Kroeze (Ligtermoet & Partners) , CROW
The Bicycle Traffic Design Indicator (CROW publication 230) is the standard reference for designers and policy makers. This index helps them find the required information.