Cyclist waiting facilities at intersections

Overview

Advanced stop boxes, advanced stop lines and hook-turn boxes provide opportunities for cyclists to wait at signalised intersections. They need to be designed with careful consideration of the signal phasing to ensure a safe and logical arrangement. Further information regarding the function, application, design, placement and phasing considerations of these storage facilities will be provided in the TCD Manual Part 4. In the interim, the guidance is provided below.

• Advanced stop boxes

  Function

  Advanced stop boxes (also known as ASBs) allow cyclists to queue at signalised intersections in front of motor vehicles during the red phase; this makes cyclists more visible to motorists and allows cyclists a physical head start at the start of the green phase. 

  ASBs across adjacent traffic lanes can also benefit cyclists by allowing them to change lanes during the red phase.

  Applications

  Whilst it is generally preferable to have an approach cycle lane leading in to an ASB, this is not necessarily required in all cases and it can be advantageous to provide at least an ASB even without an approach cycle lane.

  ASBs can be provided for movements where no departure cycle lane is available so that cyclists arriving during the red phase can wait at the head of the traffic queue and be more visible to motorists.

  Design

  Table: Specific design requirements for individual ASBs

  Size	The minimum length (L) of an ASB (ie the distance from the ASB limit line to limit line of the general traffic lane behind the ASB) is 3 m; this should be increased to 4 m in locations where large heavy vehicles are present. When a crosswalk is not at a right angle, the length (L) of an ASB should be measured as shown in the figure below. An ASB should generally be the same width as the general traffic lane behind it; however for an ASB placed in front of the rightmost traffic lane, it may be necessary to reduce this width based on tracking paths of vehicles turning into the intersection leg on which the ASB is located. In locations with annual average daily traffic (AADT) count of 300 or more heavy vehicles, ASBs with a buffer zone should be considered – see the Buffered advance stop box: design guidance note [PDF, 883 KB].
  Line style	The limit line of an ASB should follow the specifications of cycle lane limit lines, ie a 100 mm wide, white solid line.
  Colour	Green surfacing in ASBs should be used to highlight their presence.
  Markings	A cycle symbol, the same size as that used for a cycle lane in a location with a 70 km/h or greater speed limit should be marked in an ASB (see below). This should be oriented in the direction of through travel from the intersection approach leg on which the ASB is located.
  ASB length (L) definition when crosswalks are not at right angles

  Buffered advance stop boxes

  Many heavy vehicles have significant blind spots around the cab. To improve the visibility of cyclists to these drivers, a Buffered ASB may be used.

  Buffered ASBs consist of an unpainted buffer zone between the ASB and the main limit line. They improve the likelihood of drivers detecting cyclists as well as decreasing the level of vehicle encroachment into ASBs.

  Buffered ASBs should be considered at locations that have an annual average daily traffic (AADT) count of >300 heavy vehicles.

  Further guidance can be found in the Buffered advance stop box: design guidance note [PDF, 883 KB]. 

  

  Placement considerations

  There should be a 200 mm gap between an ASB limit line and the outer pedestrian crosswalk line.

  The limit line of an ASB in front of a right turn lane may need to be set back further from the pedestrian crosswalk lines to suit swept path requirements.  Alternatively, the ASB can be reduced in width, ie so that it extends across half the width of the right turn lane.  Where it is difficult for cyclists to use ASBs to turn right (eg two or more lanes need to be crossed to get into the right position, or through vehicle operating speeds are high), it is impractical to mark a right turn ASB in the intersection layout, or it is intended to provide for less confident cyclists, then a hook-turn box is the preferred method of providing for right turning cyclists.

  As shown in MOTSAM Part 2 Figure 3.34 ASBs should not:

  • extend across more than two adjacent lanes in either direction from a cycle lane

  • extend across more than two adjacent lanes if no approach cycle lane is provided

  Note that the depth of ASBs shown in MOTSAM Part 2 Figure 3.34 should be replaced with the appropriate depth specified under design of ASBs.

  Note that in some locations it would be advantageous for cyclists to be able to proceed straight ahead from an exclusive left-turning lane to ensure they remain to the left of through traffic, however this would be a breach of the Road User Rule. In this case, the lane must be unmarked so that cyclists can proceed straight ahead from an ASB placed in front of it.

  Phasing considerations

  Intersection layout and signal phasing must be considered together to ensure a safe and logical arrangement. ASBs should not be placed where cyclists waiting in them would conflict with the vehicle movement from the lane in front of which the ASB is located. The table below outlines the applications and considerations for a variety of different ASB layouts.

  Table: Layout and phasing implications of various ASB configurations

  Configuration	Phasing considerations	Advantages (+)/ Disadvantages (-)
  General – applies to all cases above (unless otherwise specified). Approach cycle lane: Whilst it is generally preferable to have an approach cycle lane leading into an ASB, this is not necessarily required or possible in all cases.   Where an approach cycle lane is not provided, it can still be advantageous to provide at least an ASB.	Cannot be used in conjunction with specific signals for cyclists if cyclists have a red light while general traffic from the same approach has a green.	+ Enables cyclists to queue at signalised intersections in front of motor vehicles; making cyclists more visible to motorists and giving them a physical head start.  + ASBs across one adjacent traffic lanes can benefit cyclists by enabling them to change lanes during the red phase.  + Particularly useful for cycle movements where no cycle lane is provided on the departure as cyclists arriving during the red phase can wait at the head of the traffic queue and be more visible to motorists when travelling through the intersection. - Generally offers no benefits to cyclists arriving during the green phase of intersection operation. - Cyclists arriving during the red phase may not be able to access the ASB if traffic lanes are too narrow or congested.
  Note: Requires left turn lane to be unmarked, so that cyclists may proceed through from ASB. A sign may be used to require all traffic to turn left from the left lane except cycles.	Cannot be operated in conjunction with a green left turn arrow – either when the through traffic has a red signal (and therefore through cyclists would block path of a left turning vehicle) or when the through traffic has a green signal (as left turning motorists may not notice cyclists approaching in a kerbside position intending to travel straight ahead). Should not be operated in conjunction with a red left turn arrow when general traffic has a green signal as cyclists wanting to turn left may block the path of motorists wanting to travel straight ahead (unless the physical layout enforces that the unmarked lane can only accommodate left turning motor vehicles).	+ Allows cyclists to retain a kerbside position on the departure - Legal requirement of unmarked lane enables motorists travelling straight through to use what would have otherwise been an exclusive left turn lane
  	Cannot be operated in conjunction with green left turn arrows – either when the through traffic has a red signal (and therefore through cyclists would block path of a left turning vehicle) or when the through traffic has a green signal (as left turning motorists may not notice cyclists approaching in a kerbside position intending to travel straight ahead). Should not be operated in conjunction with a red left turn arrow when general traffic has a green signal as cyclists wanting to turn left may block the path of motorists wanting to travel straight ahead.	+ Mitigates the safety risk associated with shared left turn and through lanes as cyclists (arriving during the red phase) can adopt a position that does not put them in conflict with the lead motor vehicle in the queue.
  		+ Research from Turner et al (2011)(external link) shows that intersection approaches with exclusive left turn lanes for general traffic are safer for cyclists than those with shared left turn and through lanes (note that this applies even in cases where there is no approach cycle lane).
  	Cannot be operated in conjunction with red or green right turn arrows (i.e. right turning and straight through traffic moves during different phases).
  Should generally be provided in conjunction with another facility that provides for cyclists travelling straight through.	No restrictions.
  Note: Requires corresponding lane to be unmarked, so that cyclists may proceed through from ASB or marked with through and right.	Assumes phasing allows through cyclists to proceed at the same time as right turning traffic.	+ This layout can provide for the scenario where straight ahead travel is only available to bicycle traffic (eg into a park) and there is no room for a cycle lane in between the general traffic lanes.

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• Advanced stop lines

  Function

  Advanced stop lines (also known as ASLs) extend a cycle lane at an intersection approach further than adjacent general traffic lanes. This makes cyclists more visible to motorists and gives cyclists a physical head start when the green phase commences. These are generally applied at signalised intersections but can be used at priority controlled intersections. 

  Applications

  Wherever cycle lanes are provided at the intersection, advanced stop lines or advanced stop boxes should be provided, including at midblock signals and adjacent to exclusive through lanes.

  Design

  Table: Specific design requirements for individual ASLs 

  Size	The default length of an ASL (i.e. the distance from the ASL limit line to limit line of the general traffic lane) is 3 m. This can be reduced to 2 m if drivers can only turn into driveways or kerbside parking beyond the intersection. This length should be increased to 4 m in locations where large heavy vehicles are present.
  Line style	The limit line of an ASL should follow the specifications of cycle lane limit lines, ie a 100 mm wide, white solid line.
  Colour	Green surfacing should be used in ASLs to highlight their presence, especially for a kerbside ASL adjacent to a general traffic lane that involves left turning vehicles or ASLs for additional cycle lanes that provide for right turning (or straight ahead) cyclists.
  Markings	A cycle symbol should be marked near the limit line in an ASL, the size of which depends on the speed limit of the location, as prescribed for cycle lanes.

   Placement considerations

  There should be a 200 mm gap between an ASL limit line and the outer pedestrian crosswalk line.

  Phasing considerations

  Intersection layout and signal phasing must be considered together to ensure a safe and logical arrangement.  ASLs should not be in placed where cyclists waiting in them would conflict with vehicle movement, for example a kerbside ASL placed next to an exclusive left-turn lane with a lead turn where turning heavy vehicles are likely  to overrun the cycle lane. The table below outlines the applications and considerations for a variety of different ASL layouts.

  Table: Layout and phasing implications of various ASL configurations

  Configuration/layout	Phasing considerations	Advantages (+) / Disadvantages (-)
  General – applies to all cases above (unless otherwise specified). Depending on the lane configuration and signal phasing, it may be preferable to provide an ASB rather than simply an ASL, as ASBs provide more space for queuing cyclists.		+ Enables cyclists to queue at signalised intersections ahead of motor vehicles; making cyclists more visible to motorists.
  	Cannot be operated in conjunction with a green left turn arrow – either when the through traffic has a red signal (and therefore through cyclists may be on the tracking path of a left turning vehicle) or when the through traffic has a green signal (as left turning motorists will be in direct conflict with cyclists travelling straight ahead).	+ Can be applied to a protected cycle facility   - Conflict between left turning motorists and straight ahead cyclists.
  	Cannot be operated in conjunction with a green left turn arrow – either when the through traffic has a red signal (and therefore through cyclists may be on the tracking path of a left turning vehicle) or when the through traffic has a green signal (as left turning motorists will be in direct conflict with cyclists travelling straight ahead).	+ Can be applied to a protected cycleway   - Conflict between left turning motorists and straight ahead cyclists.
  		+ Eliminates conflict between left turning motorists and straight ahead cyclists.  Research by Turner et al (2011)(external link) shows that intersection approaches with exclusive left turn lanes for general traffic are safer for cyclists than those with shared left turn and through lanes. - Requires a midblock transition for left turning vehicles to access left turn lane although this conflict is of less concern than the conflict arising from a kerbside cycle lane at the intersection. This may exclude the possibility of using this treatment for a protected cycleway. - Requires left turning cyclists to share the left turn lane with motor vehicles, which may result in some confusion or discomfort for cyclists.
  		+ Avoids cyclists having to share the right turn lane with motor vehicles. - Requires a midblock transition for cyclists to access the right turn cycle lane. - Unlikely to work in conjunction with protected cycleways, unless deemed acceptable to allow a section where cyclists and vehicles cross paths on the approach.

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• Hook-turn boxes

  Function

  A hook-turn box assists cyclists turning right by enabling them to do so in two stages thereby reducing the potential conflicts with other traffic. 

  The first stage involves travelling straight through the intersection, to access the hook-turn box located on the far side; this is done in parallel to adjacent through traffic. The bike rider then waits in the hook turn box until the green phase is given to traffic on the intersecting road, at which point they can travel parallel with this traffic straight through the intersection.

  Note that people on bikes can carry out a hook turn at any intersection without a specific hook-turn facility unless the intersection has a sign prohibiting this manoeuvre.

  Applications

  Hook-turn boxes are particularly useful where people on bikes find it difficult or daunting to access the right turn lane or, once in the correct approach position, to undertake the right turn through the intersection. They should be used at busy multi-lane signalised intersections, and where single through lanes to be crossed are fast and busy. Hook-turn boxes provide a higher level of service to people who are less confident riding a bicycle.

  Design

  Table: Specific design requirements for individual hook-turn boxes

  Size	The size of a hook-turn box depends on the space available and the required number of bicycles to be accommodated at any one time. A minimum area of 3 square metres should be provided, with each of the edges being at least 1.5 m long.
  Line style	The border of a hook-turn box should follow the specifications of cycle lane limit lines, i.e. a 100 mm wide, white solid line.
  Colour	Green surfacing should be used in hook-turn boxes to highlight their presence.
  Markings	A cycle symbol and directional arrow should be marked within the hook turn box, as shown in MOTSAM Part 2 Figure 3.35a. Note that the arrow is 30% of the standard turn arrow size and the cycle symbol is that for a 50km/h road. The cycle symbol and the arrow should be aligned with the direction of travel from which the cyclists access the box (ie approach 1), to avoid cyclists travelling straight through from the adjacent approach (ie approach 2) confusing the box with an advanced stop box.

  Signage

  Hook turn boxes do not require signs, however a sign has been available since May 2016 when the A43-5 Cycle hook turn(external link) gazette notice was issued.  Detailed specification on this sign(external link) can be found within the Transport Agency’s traffic sign specifications website.

  

  Optional hook turn sign(external link)

  Like other ‘information general’ signs, the hook turn signs uses black writing / symbols on a white background. The hook arrow is used to convey the manoeuvre.

  It is recommended that the hook turn sign be placed 25 m in advance of the intersection (unlike other permanent warning signs which are placed 60 m in advance).

  Layout and phasing considerations

  There should be a 200 mm gap between a hook-turn box and the inner pedestrian crosswalk line.

  The layout for a hook-turn box within an intersection depends on the phasing and configuration of the two relevant approaches relating to the two stages of the hook turn manoeuvre, and in particular the location of the cycle lanes on these approaches.  It must be ensured that cyclists waiting in the hook-turn box do not impede the travel of through cyclists and are not put into the path of any motor vehicle movements.

  The placement of hook-turn boxes in relation to cycle lanes is provided in MOTSAM Part 2 Figure 3.35.

  Layout and phasing implications of hook-turn box configurations are provided in the table below.

  Table: Layout and phasing implications of various hook-turn box configurations

  Configuration	Phasing considerations	Applications (+) /Disadvantages (-)
  	If an exclusive lead left turn phase is provided for Approach 2, the hook-turn box must be located clear of the left turning movement.  This may not be appropriate if heavy vehicles are present, depending on the site geometry.  Note that a lag left turn is technically suitable, however as there is the chance that some cyclists from Approach 2 will use the hook-turn box as an ASB, this operation should also be avoided.	- If an exclusive lead left turn phase is operated this may increase the level of discomfort to cyclists, as they will experience motor traffic passing them from two directions (initially the through traffic from Approach 1, followed by the left turning traffic from Approach 2).
  	This layout configuration cannot be employed in conjunction with an exclusive lead left turn from Approach 2.  Note that a lag left turn is technically suitable, however as there is the chance that some cyclists from Approach 2 will use the hook-turn box as an ASB, this operation should also be avoided.

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