There has been a lot of debate about the merits of a two-way track compared with having 2 one-way tracks on Cycle Superhighway 4 (CS4).   So set out below are some of the points made by Southwark Cyclist members. However, before setting these out I will summarise what is in the new London Cycle Design Standard (LCDS).

LCDS says in section 4.2.4  2-way cycle tracks

Segregated lanes/tracks and stepped tracks should generally be designed to be one-way, on either side of the road, with cycle traffic running in the same direction as adjacent general traffic lanes.

Two-way tracks on one side have practical advantages for some street types where a high degree of separation is required – for example, where there are many more side roads and greater levels of kerbside activity on one side than the other.

Where cycle flows are tidal (with significantly larger flows in one direction during the peak periods), two-way tracks can represent a more flexible use of space than one-way tracks. This is because cyclists can move out into the ‘opposing lane’ within the cycle track to overtake.

Figure 4.9 Two-way cycle tracks: opportunities and design challenges

Opportunities

• Where buildings, active uses and side roads are entirely or largely on only one side (a waterside location, for example)
• Where kerbside activity or side road access may be reconfigured so as to take place largely on one side
• Arterial roads such as wide dual carriageways with infrequent crossings
• One-way systems and gyratories

Challenges

• Can be unintuitive and generate risks associated with motorists and pedestrians not looking both ways when crossing a track
• Complex arrangements at junctions and side roads, often with some confusion about priorities (see section 5.3.4 for more details)
• Complex transitions from one-way, with-flow to two-way cycle provision
• Connectivity for cyclists to and from the track can be difficult to manage
• Need for substantial signal control, for the above reasons

Other points raised by Southwark Cyclists

• At night you are blinded by the on-coming headlights.
• Future proofing: would be easier to design well for two one-way tracks, and widen them later if numbers go up, than to design for a bi-directional track, and then have to add another on the opposite side of the road later.
• Pedestrian comfort: the presence of a cycle track moves the motor traffic further from the pavement. Better to do that on both sides, if possible.
• Sociable cycling: I like the bidirectional track at Oval, because it’s wide enough to cycle sociably, and other people can still overtake. If the one-way tracks are 2.5m wide, though, this will still be possible with one-way tracks, and will also deal with tidal flows. This may seem like quite a minor point, but I can walk, tube and bus almost everywhere in London whilst chatting to a friend. I am more likely to ride a bike instead if it can remain sociable. This will hold especially true for teenagers cycling, or adults with children.
• Space requirements. 2 x one-way = (2.5m track + 0.35m separation) x 2 = 5.7m, whereas 1 x bidirectional = 4m + 1m separation = 5m. I assume the larger buffer with bidirectional is because of the risk of head-on collisions, and to give turning drivers more time to slow down and spot cyclists (and vice versa). So the one-way tracks aren’t actually taking up very much more road space, if TfL kept to those standards. At which point, better to just make the one-way tracks wide enough to deal with tidal flow?
• Marketing: currently, a bidirectional track says “this is a special cycle route”. Cycling tracks on both sides of the road would say “bikes also use this road”. I wonder if it is easier to slowly spread one-directional cycle tracks, so that they become, like pavements, something on every busy road; whereas bidirectional tracks are more of a Route.

Summary

The LCDS sums it up: Segregated lanes/tracks should generally be one-way, on either side of the road. Most of the points made by Southwark Cyclists favour one-way tracks. A two-way track may be suitable where activity and side roads are entirely or largely on one side and/or where flow is very tidal. A problem here is how we decide that activity is “largely” on one side. TfL decided this was the case for Blackfriars Road (see header picture), but in fact the differences between east and west sides are barely perceptible.

What about CS4?

Cycle traffic on CS4 at peak is very tidal with about a 10:1 ratio between directions. Thus a 2-way track will provide more space. And space will be needed as flows are already 1000/hr at peak. Jamaica Rd is very much quieter on the north (river) side than on south side. So there is a strong case for a 2 way track on the north side of Jamaica Road up to Southwark Park, i.e. from Dockhead to Southwark Park Rd. For the stretch past Southwark Park, the south or southeast side becomes much quieter than the river side. So a case can be made for switching the 2-way track across the road. At Surrey Quays much depends on how the gyratory is changed. The plan is to remove the gyratory and put a 2-way track on the north side. So another switch of sides is required. For the stretch from the gyratory to Greenwich (Evelyn St, Creek Rd) the northeast (river) side has fewer main junctions. Whether this makes a 2-way track the best option is still under discussion.

Overall there does appear a pretty strong case for a 2-way track, despite the fact that this is not, generally, what cyclists prefer. The cycle flows are very tidal and there are fewer major turnings on one side or the other. London Cycling Campaign (LCC) has been shown the latest plans in confidence, so it is not possible to spell out in detail what TfL may propose in the public consultation in early 2016. We will just have to wait and see. However, the LCC will be lobbying TfL for a 2-way track on most of the route.