Friday 21 November 2008

Cycle Infrastructure

There is now a fairly long Department of Transport document up online on "Cycle Infrastructure Design"

It covers when to/when not to segregate bikes from other road traffic, how to do safe cycle facilities, etc.

Two obvious failings
  1. No awareness of mountain bikes. Not only do things like A-frame motorbike barriers get in the way, a lot of their cycle speed calming measures are just a form of entertainment to a mountain bike in a hurry. Hopefully the Bristol Trails Group won't see their recommendations about track surface, minimum distance from trees, etc.
  2. Roundabouts (p58). The document acknowledges their danger, especially those with left-feeds, and discusses how bigger radius roundabouts (e.g. St James Barton, St Pauls/M32 and Lawrence Hill roundabouts) allow cars to get up more speed and are more dangerous. But a key suggestion is "not generally recommended on cycle routes.". Given the data they cite on roundabout design, surely we should be considering -if cycling is to be considered a legitimate form of transport- whether roundabouts should still be being built. After all, if unmanned level crossings are being withdrawn for safety reasons, why can't we have a "no new roundabouts" policy. It may seem ambitious, but round-is-bad.
[photo: a shopping centre with overflowing bike parking. Clifton Down, not Cabot Circus]


Anonymous said...

There is really no reason for Roundabouts to be a hazard for bikes: The solution is simply to have a bike roundabout around the outside, with the same rules about direction, and priority for bikes where they cross the road.

Of course that takes up space so the roundabout has to be smaller, which makes cars slower.

One important thing is good visibility so drivers can see cyclists and give priority and a space for cars to stop between roundabout and bike lane

This utopian ideal does exist. Not in our village, but here's an example to the south of us:,9.1471&spn=0.000854,0.002747&t=h&z=19

One major difference in our law is that a red cycle lane means bikes have priority and cars must give was. Also, if a car hits a bike or pedestrian anywhere, it's assumed to be the car drivers fault unless they can prove otherwise. This could be a problem in the UK because the law is different.

SteveL said...

That design is discussed in the doc; they do exist in places -I know of one in Portsmouth. The problem is the drivers need to participate, otherwise the bike has just given up the option of having any right of way. Then you end up trying to cycle across the exit of a car coming out of the junction at speed.

Anonymous said...

I can see that- that's the difference the law makes here: drivers that hit cyclists are in a lot of trouble, and if it's a red lane even more so. Because drivers know this, they tend to be more careful than in the UK.

Anonymous said...

Wouldn't that be nice to have that in Bristol unlike the russian roulette cycle lane vs roundabout "design" we have at the St James Barton roundabout.

Bristol Traffic said...

St James B isn't as lethal as it was, because of the lights. You do have to sprint across lanes, but its slower. The St Pauls/M32 roundabout is still bad though, even with the lights -possibly because the uphills ruin your ability to accelerate out.

We should maybe do some special filming of those roundabouts.