Advanced stop line
Encyclopedia
An advanced stop line (ASL), also called advanced stop box or bike box, these are road markings at signalised road junctions allowing certain types of vehicle a head start
when the traffic signal changes from red to green.
s, they may also be provided for bus
es and motorcycle
s. There are two parallel stop lines at the intersection, the first one at which all traffic except that for which the facility is provided must stop, and a second one nearer the intersection to which only specified vehicles may proceed. The area between the stop lines is the "reservoir" or "box". Signage may be required to inform road users as to the meaning of the extra stop line. A separate set of traffic signals may be provided for the specified traffic, but all vehicles usually use the same signals.
in the US).
At a red light, cyclists are more visible to motorists by being in front of them. At a green light, the green bike lane through the intersection reminds motorists and cyclists to watch for each other.
Although waiting cyclists might be safer out in front of HGVs, concerns have been expressed about nearside cycle lanes approaching such intersections may encourage cyclists to "creep up" on the inside of turning HGVs. Collisions with turning HGVs are strongly associated with a high risk of death and serious injury. The 1997 edition of Cyclecraft by John Franklin advises cyclists that they should use such feeder lanes only if the traffic signal is red. If the signal is green, cyclists are advised that the best way to minimize danger may be to stay within the main traffic stream. If the lights change while the cyclist is still approaching, the advice is to negotiate their way back into the main traffic stream if possible. Advice produced by RoSPA regarding cyclists and lorries cautions cyclists that even though a junction has an ASL it may be better to hang back if there is a lorry present.
Portland, Oregon has implemented these "bike boxes" as they call them, to which bicyclists have claimed useful in aiding safety. The main goal is to prevent collisions between motorists turning right and cyclists going straight. Research performed by the Oregon Transportation Research and Education Consortium showed that motorists and cyclists alike appear to understand and comply with the boxes. Nearly three quarters of motorists stopped behind the bike box and roughly the same percentage of cyclists stopped at the proper location ahead of the motor vehicle stop bar. In addition, the number of conflicts at the intersections decreased and drivers yielded more to cyclists after the boxes were installed. User perceptions of safety also improved.
A leaflet produced by the UK Department for Transport notes:
Head start (positioning)
In positioning, a head start is a start in advance of the starting position of others in competition, or simply toward the finish line or desired outcome...
when the traffic signal changes from red to green.
Description
Most commonly associated with bicycleBicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s, they may also be provided for bus
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
es and motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...
s. There are two parallel stop lines at the intersection, the first one at which all traffic except that for which the facility is provided must stop, and a second one nearer the intersection to which only specified vehicles may proceed. The area between the stop lines is the "reservoir" or "box". Signage may be required to inform road users as to the meaning of the extra stop line. A separate set of traffic signals may be provided for the specified traffic, but all vehicles usually use the same signals.
Cyclists
ASLs for cyclists are generally used in conjunction with some form of cycle lane for filtering cycle traffic. Traffic regulations in some countries (eg UK and Ireland) may require a cycle lane to give cyclists a legal way of bypassing the first stop line. This arrangement theoretically allows cyclists to play to their strengths by regularising the practice of filtering to the top of queuing traffic during the red phase at traffic lights. Cyclists turning to the offside (ie right in the UK and Ireland, left in USA etc) are able to take up a proper turning position. Straight-on cyclists can adopt and maintain a prominent position for transiting the junction safely within the main traffic stream. An ASL will also help reduce the exposure of such cyclists at junctions with nearside (ie left in the UK and Ireland, right in USA etc) filter lights by providing a place for cyclists to wait while traffic passes on the inside. A similar consideration arises where a free turn to the nearside is permitted (called right turn on redRight turn on red
Right turn on red, or simply right on red, is a principle of law permitting vehicles at a traffic light showing a red signal to turn right when the way is clear, in a country with right-hand traffic...
in the US).
At a red light, cyclists are more visible to motorists by being in front of them. At a green light, the green bike lane through the intersection reminds motorists and cyclists to watch for each other.
Safety aspects
Based on Danish research, it is argued that an ASL should have the general stop line 5 m back from the main traffic signal. The reasoning is that this puts cyclists clearly into the view of HGV (heavy goods vehicles) drivers, who have a blind spot up to 4 m directly in front of the cab. According to an OECD review, ASLs are also advocated as way of improving pedestrian safety at crossings by increasing the separation between crossing pedestrians and waiting motor vehicles.Although waiting cyclists might be safer out in front of HGVs, concerns have been expressed about nearside cycle lanes approaching such intersections may encourage cyclists to "creep up" on the inside of turning HGVs. Collisions with turning HGVs are strongly associated with a high risk of death and serious injury. The 1997 edition of Cyclecraft by John Franklin advises cyclists that they should use such feeder lanes only if the traffic signal is red. If the signal is green, cyclists are advised that the best way to minimize danger may be to stay within the main traffic stream. If the lights change while the cyclist is still approaching, the advice is to negotiate their way back into the main traffic stream if possible. Advice produced by RoSPA regarding cyclists and lorries cautions cyclists that even though a junction has an ASL it may be better to hang back if there is a lorry present.
Portland, Oregon has implemented these "bike boxes" as they call them, to which bicyclists have claimed useful in aiding safety. The main goal is to prevent collisions between motorists turning right and cyclists going straight. Research performed by the Oregon Transportation Research and Education Consortium showed that motorists and cyclists alike appear to understand and comply with the boxes. Nearly three quarters of motorists stopped behind the bike box and roughly the same percentage of cyclists stopped at the proper location ahead of the motor vehicle stop bar. In addition, the number of conflicts at the intersections decreased and drivers yielded more to cyclists after the boxes were installed. User perceptions of safety also improved.
A leaflet produced by the UK Department for Transport notes:
External links
- Do Advanced Stop Lines Work? London Cycling CampaignLondon Cycling CampaignThe London Cycling Campaign is an independent membership charity lobbying for better conditions for cyclists in London. Its vision is to make London "a world-class cycling city"...
group evaluates ASL performance in Westminster, UK