An advanced stop line (ASL), also called advanced stop box or bike box, is a type of road marking at signalised road junctions allowing certain types of vehicle a head start when the traffic signal changes from red to green. Advanced stop lines are implemented widely in Denmark, the United Kingdom, and other European countries but the idea was first conceptualized by transportation planner Michael Lynch for the city of Portland, Oregon, in response to numerous bike crashes at intersections. [1]
Most commonly associated with bicycles, they may also be provided for buses and motorcycles. 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. If the signals change to red when a vehicle is crossing the first line, the driver must stop at the second line [2] 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.
ASLs for cyclists are generally used in conjunction with some form of cycle lane for filtering cycle traffic. 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 (i.e. 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 (i.e. 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 red 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.
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 heavy goods vehicle (HGV) drivers, who have a large blind spot directly in front of the cab. FMCSA however estimates this spot to be 6 metres (20 ft) long. [3] According to an Organisation for Economic Co-operation and Development (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. [4]
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. [5] 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 the Royal Society for the Prevention of Accidents (RoSPA) regarding cyclists and lorries cautions cyclists that even though a junction has an ASL it may be better to wait if there is a lorry present. [5]
Portland, Oregon, has implemented these "bike boxes" as they call them, and bicyclists have claimed them useful in aiding safety. The main goal is to prevent collisions between motorists turning right and cyclists going straight. [6] 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. [1]
A leaflet produced by the UK Department for Transport notes: [7]
ASLs have been used successfully at sites with motor vehicle flows up to 1000 vehicles per hour, and with two-lane approaches. In Bristol they have been used on the approach to a signalised roundabout. Success will depend on motorists not blocking the cycle lane or encroaching on the reservoir, and on signal timings which ensure that cyclists are not frequently stopped.
A roundabout, also known as a rotary or traffic circle, is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.
An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections are often delineated by gores and may be classified by road segments, traffic controls and lane design.
Traffic lights, traffic signals, or stoplights – also known as robots in South Africa and Namibia – are signalling devices positioned at road intersections, pedestrian crossings, and other locations in order to control the flow of traffic.
A curb extension is a traffic calming measure which widens the sidewalk for a short distance. This reduces the crossing distance and allows pedestrians and drivers to see each other when parked vehicles would otherwise block visibility. The practice of banning car parking near intersections is referred to as daylighting the intersection.
A jughandle is a type of ramp or slip road that changes the way traffic turns left at an at-grade intersection. Instead of a standard left turn being made from the left lane, left-turning traffic uses a ramp on the right side of the road. In a standard forward jughandle or near-side jughandle, the ramp leaves before the intersection, and left-turning traffic turns left off of it rather than the through road; right turns are also made using the jughandle. In a reverse jughandle or far-side jughandle, the ramp leaves after the intersection, and left-turning traffic loops around to the right and merges with the crossroad before the intersection.
A hook turn or two-stage turn, also known as a Copenhagen Left, is a road cycling manoeuvre or a motor vehicle traffic-control mechanism in which vehicles that would normally turn from the innermost lane of an intersection instead turn from the outermost lane, across all other lanes of traffic.
Vehicular cycling is the practice of riding bicycles on roads in a manner that is in accordance with the principles for driving in traffic, and in a way that places responsibility for safety on the individual.
Bicycle transportation planning and engineering are the disciplines related to transportation engineering and transportation planning concerning bicycles as a mode of transport and the concomitant study, design and implementation of cycling infrastructure. It includes the study and design of dedicated transport facilities for cyclists as well as mixed-mode environments and how both of these examples can be made to work safely. In jurisdictions such as the United States it is often practiced in conjunction with planning for pedestrians as a part of active transportation planning.
Bicycle safety is the use of road traffic safety practices to reduce risk associated with cycling. Risk can be defined as the number of incidents occurring for a given amount of cycling. Some of this subject matter is hotly debated: for example, which types of cycling environment or cycling infrastructure is safest for cyclists. The merits of obeying the traffic laws and using bicycle lighting at night are less controversial. Wearing a bicycle helmet may reduce the chance of head injury in the event of a crash.
A junction is where two or more roads meet.
Road signs in Sweden are regulated in Vägmärkesförordningen, VMF (2007:90), and are to be placed 2 metres from the road with the sign 1.6 m from the base for motorized roads. Except for route numbers, there are a maximum of three signs on a pole, with the most important sign at the top. All signs have a reflective layer added on selected parts of the sign as is custom in European countries; most larger signs also have their own illumination.
A cycle track or cycleway (British) or bikeway, sometimes historically referred to as a sidepath, is a separate route for cycles and not motor vehicles. In some cases cycle tracks are also used by other users such as pedestrians and horse riders. A cycle track can be next to a normal road, and can either be a shared route with pedestrians or be made distinct from both the pavement and general roadway by vertical barriers or elevation differences.
Road signs in Singapore closely follow those laid down in the traffic sign regulations used in the United Kingdom, although a number of changes over the years have introduced some slight deviations that suit local road conditions. Road signs in Singapore conform to the local Highway Code under the authority of the Singapore Traffic Police.
In road design, a slip lane, also known as a filter lane in the United Kingdom, is a road at a junction that allows motorists to change roads without actually entering an intersection.
Cycling infrastructure is all infrastructure cyclists are allowed to use. Bikeways include bike paths, bike lanes, cycle tracks, rail trails and, where permitted, sidewalks. Roads used by motorists are also cycling infrastructure, except where cyclists are barred such as many freeways/motorways. It includes amenities such as bike racks for parking, shelters, service centers and specialized traffic signs and signals. The more cycling infrastructure, the more people get about by bicycle.
A protected intersection or protected junction, also known as a Dutch-style junction, is a type of at-grade road junction in which cyclists and pedestrians are separated from cars. The primary aim of junction protection is to help pedestrians and cyclists be and feel safer at road junctions.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
There is debate over the safety implications of cycling infrastructure. Recent studies generally affirm that segregated cycle tracks have a better safety record between intersections than cycling on major roads in traffic. Furthermore, cycling infrastructure tends to lead to more people cycling. A higher modal share of people cycling is correlated with lower incidences of cyclist fatalities, leading to a "safety in numbers" effect though some contributors caution against this hypothesis. On the contrary, older studies tended to come to negative conclusions about mid-block cycle track safety.
One of the potential pitfalls for observers trying to interpret the operation of bikeways is that the same legal assumptions do not apply in all environments. For instance, in contrast to most English speaking countries, some European countries, including Germany, France, Denmark, Belgium, and the Netherlands have defined liability legislation. Thus there is a legal assumption that motorists are automatically considered liable in law for any injuries that occur if they collide with a cyclist. This may hold regardless of any fault on the part of the cyclist and may significantly affect the behaviour of motorists when they encounter cyclists.
Traffic lights – devices positioned at road intersections, pedestrian crossings and other locations – control flows of traffic with social norms and laws created by the state. Traffic signals have to convey messages to drivers in a short period of time about constantly-changing road rules.
Bike boxes and similar advanced stop lines are used extensively in the United Kingdom, the Netherlands, Denmark, and other European countries. Observations of yielding behavior at two bike box and one control intersection found an improvement in motorists yielding to cyclists at the bike box locations. Higher shares of surveyed motorists felt that the bike boxes made driving safer rather than more dangerous, even when the sample was narrowed to respondents who were not also cyclists. Over three-quarters of the surveyed cyclists thought that the boxes made the intersection safer.
In the Swedish study mentioned earlier (Linderholm, 1992) ... analysis of the before-after situation showed that a recessed stop line for motor vehicles reduced the accident risk for cyclists crossing by about 35 per cent. ... In Denmark, the Danish Road Administration (1994d) carried out a study at four signalized junctions, where the stop line for motorists was recessed by five metres.... In the before period, between 12 and 24 per cent of the drivers turned right straight in front of a cyclist. In the after period, only 3 to 6 per cent did. On the basis of these results, safety of cyclists could be expected to improve. TRL in England (Wheeler, 1992) studied advanced stop lines (ASL) for cyclists at signalized junctions. ... The number of cyclists having a good position before turning right went from 57 per cent to 97 per cent.
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