Current Design Practices & Recommendations
A discussion on various types of cycle facility, and CCC's "best practice" recommendations. Paul Gasson
In London, the growing London Cycle Network aims to provide a series of interconnected safe cycle routes between various local centres. The concept is great, but the execution is distinctly third rate. Facilities for cyclists generally tend to predominate where road space can be allocated to cyclists with little opposition from other road users, and will either peter out, or follow a circuitous bypass, when approaching a hazard which requires more than nominal design effort. The main types of dedicated cycle facilities are:
- Cycle Lanes
- Cycle Tracks
- Shared pedestrian/cycle path
- Advance Stop Lines
- Road Closure Cycle Gaps
The majority of cycle
facilities in the UK are painted cycle lanes, which may have a dotted white line defining the ourside of the lane to signify that they are
advisory, or a solid white line to indicate that they are
Mandatory lanes may either be operational for part of the day (often peak commuting hours - eg 8-10am & 4-6pm), or less commonly may be operational 24 hours a day. Motorists are not allowed to drive or park in mandatory lanes. Note however that black taxi cabs have won exemption from some central London mandatory cycle lanes, and are allowed to stop in them to drop off and pick up passengers; this tends to undermine mandatory lane compliance from other motor vehicle users.
Advisory lanes cannot be enforced (ie motorists are allowed to drive in them and can park in them, subject to yellow line restrictions). Local authorities sometimes use them when the carriageway is not wide enough for motor vehicles to stay out of them; this can cause cyclists to have a false sense of security when using them.
How not to do it. An advisory lane in Amwell Street, Islington, where cyclists are in for a surprise if they think they are safe - the lane terminates just where the road is pinched by a traffic island and there's a left turn into a busy one way street. In CCC's view the advisory lane markings should have been continued straight past the island and side road.
The standard width for with-flow cycle lanes should be 1.5 metres, with an absolute minimum width of 1.2 metres (note that the Disability Discrimination Act may effectively increase this to 1.5 metres). Lane widths less than this encourages less experienced cyclists to ride out of the main field of motorists' vision and leaves insufficient space after taking into account drain gratings (and the humps and dips which often surround them), ragged road side edges, and the inevitable gutterfulls of broken glass & other debris.
A more fundamental disadvantage to kerbside lanes is that the more experienced cyclist tends to cycle1 metre or more away from the kerb (or parked cars) in order to
claim a safe piece of road space. In this position motorists are more likely to treat cyclists as legitimate road users, and will hold back from overtaking until it is safe to do so, and give cyclists reasonable clearance. Thus in free flowing traffic experienced cyclists will ride in the vicinity of the white line along the outer edge of a 1 metre wide lane. And less experienced cyclists are encouraged by the existence of kerbside lanes into adopting poor cycling positioning near the gutter, and are likely to maintain this position when there is no cycle lane.
A futher safety problem is the use of kerbside cycle lanes on the approach to junctions with a left turn (see later section on advance stop lines).
One clear advantage of cycle lanes is they encourage better lane discipline for motor vehicles, so that cyclists are more easily able to get to the front of a queue of stationary or slow moving vehicles. However the existence of a cycle lane may cause cyclists to be less aware of the dangers of car doors suddenly opening in their faces, or motorists moving into the cycle lane without warning.
Common sense should be applied when determining the alignment of cycle lanes, which should be free of unneccessary bends which could lead to inattentive motorists encountering cyclists pulling into their path. Most cyclists will tend to cycle in as straight a line as they can, and will ignore thus the alignment pictured below, although less experienced ones may follow the proscribed route and have to slow down to do so.
In this instance this cycle lane (Hunter St, WC1) was a
freebie thoughtfully added by Camden's Highways Engineering Department after resurfacing the road. However the lane swings in towards the kerb just where a major car park exit is located. And the point in the middle distance where the track swings out to skirt the car parking bays throws obedient cyclists into a potential collision point with overtaking cars, which are cutting inwards to avoid the central traffic island (a pedestrian refuge).
Where lanes are bypassing parking bays, it is essential that the inside of the lane be marked at an absolute minimum distance of 0.9 metre away from the parking bay (see below), as opening car doors are a very real threat for cyclists*; a 1.2 metre gap between the parking bay and the lane is strongly recommended, even if it means the actual cycle lane itself is only 0.5 metres wide.
In March 2002 CCC formally presented 2 different solutions to the council for cycle lanes running past parking bays; see the policy note and design schematic here.
- London Accident Analysis Unit briefing July 2001 states that 10% of London cyclist deaths and serious injuries were due to the cyclist hitting an open vehicle door.*
Virtual Nirvana image processing shows how the Hunter Street cycle lane (previous photo) should have been marked, with no kinks, and clearance from parked car doors.
Where an advisory or mandatory cycle lane passes a traffic island, the lane markings should always be continued past the island no matter how narrow the remaining road width; see our formal policy on cycle lanes past traffic islands plus a schematic here.
Where cycle lanes or tracks join the main highway, they should have a maximum angle of 15 degrees (angle between lane and carriageway kerbline), and a maximum lip between cycle lane surface and carriageway of 1cm. Bends should ideally have a minimum radius of around 10 metres, and certainly no less than 5 metres.
Wherever possible, cycle lanes should continue over junctions. Where the cycle lane is on the major road, broken lines & green surfacing should be used. Where a lane on is on a minor road crossing over a major road, if dotted lines will conflict with existing give way markings, the lane should be continued without dotted lines but with the green surface.
Whilst any type of painted lane
helps at the margins, it is not going to encourage a vast influx of new people to take to travelling around town by bicycle.
*A mandatory cycle lane in Camden Street, part of the Traffic Director for London's unpopular
Red Route through the heart of Camden Town.*
These are dedicated lanes for cyclists, where there is a physical barrier to prevent use by motor vehicles. There are few in London, and we believe that there need to be many more. They can be expensive to build, mainly as government regulations stipulate that any bollard on an island used to define the lane should have a 0.4 metre width of traffic island on either side.
Cycle tracks have a number of advantages:
- they represent an unambigous reallocation of road space from motor traffic to cycles.
- by physically narrowing the main carriageway width, motor traffic capacity is reduced & motor vehicle speeds are lowered.
- they encourage non-cyclists to take up cycling
Note that the provision high levels of safety across unsignalled junctions poses interesting design challenges; we recommend that such junctions have raised speed tables across the entire junction, and clear signage and markings indicating which road has priority.
Where the cycle track crosses a minor side road, the cycle track should have the same priority over the side road as given to motor vehicles on the main carriageway; ie the cycle track should not have give way markings on it, as it will lessen the value and usage of the cycle track.
The absolute minimum width for a one way track should be 1.5 metres; however at this width the scheme designer should really be asking whether this facility is of genuine benefit to cyclists. CCC recommends never dropping below 2 metres for short sections of track (<= 50 metres); 2.5 metres is required for longer sections in order to allow cyclists to safely overtake one another (cyclist speeds typically vary between 8 mph and 20mph).
For two way tracks the absolute minimun width should be 2.5 metres, with a preferred standard 3 metre width.
Cycle flows need to be considered when setting track widths. The Dutch
Sign up for the bike design manual states that less than a 2 metres for a one way track
is not a good cycle facility. Ideally the track would be 2.5 metres wide, which according the Dutch would support upto 750 cycles per hour. They say that a 1.5 metre one way track will only support 150 cycles per hour.
All widths above refer to the track itself, and exclude the segregating island.
Bollard spacing should be such that tricycles and human powered delivery vehicles are able to use them, which means that the gaps between the bollard and kerb/island must be no less than 1.3 metres plus. The Disability Discrimination Act which comes into force in 2004 suggests that the future minimum width in practice will be 1.3 metres plus 100mm clearance - a total of 1.5 metres.
Note that in Camden we have found there are 2 track surfacing related issues. Firstly mechanised surface layers are unable to lay down in less than 3 metre widths, and manually laid surfaces are usually considerably inferior (noticeably bumpier than the main carriageway adjacent). Some cyclists will decide to avoid the track surface on the grounds of comfort. One workaround to this might be to lay down a 3 metre wide surface using a machine before the segregating island is constructed. The second issue is that the when the green surfacing is applied loose gravel is left over; this type of treatment on carriageway surfaces used by motor vehicles is normally fairly quickly
swept into the gutter. For cycle tracks this can lead to skids and must be removed by hand before the track is opened for use.
For more guidance on cycle tracks see here:
- Royal College Street case study - Seven Stations Link route design
Royal College Street (one way for motorists). A 50 metre section of physically segregated cycle track was originally built by the GLC in 1986, but was extended to 450 metres by Camden Council in February 2000; it now runs from the Georgiana Street to the signalled cycle crossing at Crowndale Road junctions. A key feaure of this route is that cyclists have priority over vehicles emerging from side roads. Unfortunately this junction priority is only indicated via stop or give way carriageway markings and amber flashing lights; ideally it would have physical measures such as speed tables to reinforce priority.
Shared pedestrian/cycle path
These are usually very popular facilities for cyclists as they are normally motor vehicle free; they are often used across parks, may provide a short inconnection between streets, or may run alongside a road. They can either be shared, or segregated with a white line to delineate which half is to be used by pedestrians, and which by cyclists. In the Campaign's experience the additional signage and hence cost of segregation is generally wasted unless cycle flows are quite high, as many pedestrians will take little notice of which half they are supposed to be in, and this can cause some cyclist/pedestrian arguments.
We are generally against the provision shared cycle and pedestrian paths which run alongside roads, as we argue that pedestrians lose pavement space and risk collisions with cyclists, which discourages walking. Council policy is to encourage walking & cycling, and discourage car use, hence we suggest that its motor vehicles which should be losing the road space.
In our view, segregation should only be used in parks (which are primarily for relaxation/leisure activities) when it is proved necessary, as pedestrians should be able to forget about traffic systems and lanes; and all the logos and signs on posts can substantially
degrade a park unless it has few natural merits.
Advance Stop Lines
Advance stop lines (ASL) at traffic signals (where cyclists are able to filter up to the front of traffic queued at a red light) are becoming increasingly popular with local authorities, as cyclists are in front of cars when the lights are change and thus very visible, and can often complete their junction manoeuvre before motor vehicles catch up with them. ASLs usually have a
feeder cycle lane running adjacent to the kerb.
ASLs do not help cyclists who arrive at a junction when the lights are green. Moreover, when there is a kerbside feeder cycle lane, cyclists are encouraged to adopt a kerbside position, which is definately the least safe place to be positioned when there is left turning motor traffic alongside or close by. The most common occurrence of dangerous motorist manouvres for cyclists is the motorist accelerating past a cyclist on the approach to a left turn, and cutting across the cyclist's bows... sometimes misjudging to the extent that the cyclist has to make an emergency stop, and occasionally such that the cyclist is unable to avoid a collision.
It is easy to harbour the suspicion that as ASLs are cheap to implement, and are highly visible signs that a council is
doing something to help the environment. This is reinforced by the emergence of ASLs which have no
feeeder cycle lane, which is normally due to narrow traffic lanes, and the council not being prepared to lose a line of queued traffic if there are two or more lanes. But this begs the question of how cyclists are supposed to reach the ASL safely if cars are packed that tightly.
Motorist compliance of ASLs seems to decrease the closer you get to central London, and enforcement of them is currently (Jan 2003) unheard of.
The legal status of ASLs has now been clarified and they are now fully enforceable following Parliamentary legislation which came into force on 31st January 2003: Anyone driving a motor vehicle which stops in an ASL when the light is red will be committing an offence contrary to section 38 of the Road Traffic Act of not obeying a traffic signal.
Its difficult to believe that when this taxi driver stopped at this red light he did not understand the significance of a green box sporting a large cycle logo - its far more likely he just did not care. Agar Grove/St Pancras Way, NW1
A valiant attempt by neighbouring Islington to spell out what the green ASL box is for ... blind motorists really should not be allowed on the roads! Location: Graham Street, Islington.
Advance stop lines should extend across all traffic lanes from the kerb to the centre line, as urban motoring practices means few drivers will stop where they should if the vehicle in the next lane is ahead of them.
This ASL is limited to just the lane on the right of this picture, and it is rare for motorists to stop behind it. Camden High Street (a Red Route).
For the same reason, advance stop lines should be perpendicular to traffic lane markings, even if the main stop line runs at an angle to the kerb.
When proposing an ASL for a junction, the Campaign always points out that pedestrians will also benefit - by pushing motor vehicles back from the crossing point, pedestrians will not be intimidated by a phalanx of vehicle bumpers lined up inches from where they cross.
Road Closure Cycle Gaps
One measure which is of undoubtable benefit is cycle gaps in road closures. Such roads tend to be very lightly trafficked, and thus offer ideal bypasses to clogged road systems. The downside is that increasing pressures on available car parking space often results in these facilities being obstructed by parked vehicles, with the only remedy either strictly enforced parking controls, or bollards/kerbs to keep a clear throughfare for cyclists. See here for a design to minimise such obstruction.
An example of good aethsetic design for a cycle track through a long road closure; but this scheme has a practical drawback in that cyclists have difficulty in crossing into the busy road at the other end. Location: Stratford Villas/Agar Grove, NW1
So, whilst these design standards might have been sufficient 20 years ago for most roads in London, the inner urban reality today is that the pressure on road space, and thus the tendency for motorists to utilise whatever spaces they can get their wheels into, means that
physical measures (such as kerbs or bollards) are often required to cordon off carriageway space to give cyclists sufficient levels of safety. Also, properly designed facilities to protect cyclists when crossing junctions are becoming essential if we are to see anything other than a nominal increase in cycle usage.
A cycle facility?
A Traffic Director funded (so-called) cycle crossing of the Finchley Road Red Route (from Fortune Green Road to Platts Lane); this crossing is on a London Cycle Network route.
© Paul Gasson