Tag:cycleway=asl

Schematic illustration of advanced stop line markings.

A cycleway advanced stop line (ASL), also known as a bike box or an advanced stop box, is a marked area for cyclists in front of the stop line for motor traffic. They are most commonly found at traffic-light controlled junctions and allow cyclists a head start when the traffic signal changes from red to green.

Usage

• A cycleway=asl is placed on the stop line for cyclists, at the front of the painted box
  • Do not place the on the motor traffic stop line
  • Do not place the on the junction node itself. This is misleading because then nobody can tell which direction of approach the ASL applies to.
• A direction=forward/backward tag is needed, unless it is a one-way road.

Note that the highway=traffic_signals node may be found either before or after the cycleway=asl node. That is because highway=traffic_signals nodes are placed on either the junction node itself, or on each of the stop lines for general (motor) traffic around the intersection. In the latter case, the highway=traffic_signals node represents both the traffic signal and the location of its motor traffic stop line, leaving no room to add something in between the two. Currently there does seem to be a way to individually tag the location of the traffic signals and the location of the stop line for motor traffic.

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  Example with a single highway=traffic_signals placed on the intersection node
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  Example with multiple highway=traffic_signals nodes placed on the stop lines for motor traffic

Further Information

Rationale and status

• These cycle facilities are common sights in UK cities and places like Portland, Oregon, USA. Junctions using them should be tagged, since their presence may be informative for cycle routing.

• "Advanced Stop Line" is the British English term for these facilities. "Bike box" is also documented here, but Wikipedia prefers the former.

• Abbreviations are short and sometimes easy to remember.

Routing and data model

No fancy relation is necessary, which keeps things simple for mappers. ASL nodes are always connected to their junctions by the way they're on. Find the nearest highway junction node along the way it's on, and that gives you both the associated junction and the applicable direction.

Open issues

• Feeder (cycle) lane vs not?
  • If the feeder cycle lane goes for a significant distance along the road, then cycleway=lane will have been used. If it's a very short feeder cycle lane, you could cut the way and tag that short way with the lane, with the way being the length of the cycle lane.
• ASLs for other types of vehicle. Are there any?