Sunday, 14 September 2008

Roundabouts revisited again

disgruntled asked, on an earlier post, what answers the Cyclecraft book gave to the problems of negotiating multi-lane roundabouts. This is my attempt to summarise quite a rich mine of advice and suggestions. Before I start let me say that there are about four pages in the book on multi-lane roundabouts alone, and more than two hundred pages on different aspects of cycling: it is well worth studying the original source.

The first point I take from the book is that the best route for a cyclist to take round a multi-lane roundabout is much the same as a car would take: using the outer lane to turn left (we are in the UK); the centre lane to go straight ahead, and the inner lane to turn right.

The second point is that the main dangers to a rider on a multi-lane roundabout are when passing an entrance (because cars entering the roundabout may not see you); and when jockeying for position on the roundabout itself (because of the different speeds of cars and bike).

I think we had pretty much figured those out already, though I hadn't really taken on board the fact that, despite the problems of jockeying for position on the roundabout itself, you definitely do not want to be riding in the outside lane, when you pass an entrance with multiple lanes of cars joining the roundabout.

Reading on, the advice gets even more interesting.

In his book, John Franklin works through three different scenarios: for turning left, carrying straight on, and turning right. Much of the advice seems to centre on making sure that you maintain control of your lane. You do this, firstly by taking position early on approach to the roundabout: in the inner, middle, or outer lane depending on which direction you are going to head. If there are only two lanes on approach, then the best position for going ahead is the right hand (outer) edge of the left hand (inner) lane. Otherwise it is the centre of the middle lane. If turning left or right, then take up the centre position in the appropriate lane.

For me, some of this is counter-intuitive, but on reflection it makes good sense. The temptation is to make it easier for cars to pass, but in reality the best strategy is to make it clear that they shouldn't.

The same principle seems to apply to the advice on turning left: use the outer lane of the roundabout (left side), but keep well away from the kerb. The book specifies about 7 feet, or 2 metres, which sounds like almost the width of lane that a car needs - i.e. clearly enough to stop anyone passing in the same lane, and not enough for anyone to cut between you and the kerb.

For turning right, the advice is to use the outer edge of the inner lane around the roundabout: again seemingly with the intent of controlling the lane, without letting anyone overtake between you and the kerb. The book states the obvious when it says you need to signal clearly when starting to spiral out of the roundabout, but I imagine that by taking this position on the outside of the lane you are already indicating your next move to any following drivers.

Other pieces of advice include being ready to take evasive action, while not making any sudden changes of direction. Not to try and change gear while negotiating the roundabout (unless you have to drop speed suddenly), but to chose a gear beforehand that allows a relatively high speed, being ready to put on a spurt of speed if necessary.

He also describes some negotiation techniques to show drivers when you are determined to make a move (such as taking up a position on the edge of the lane you intend to enter, targeting a particular driver to make way for you, and engaging eye contact). Finally, he makes the point that on very busy roundabouts you can sometimes use other vehicles as a shield, particularly when they have made way for you to change lane.

In summary, the book doesn't pretend that this is easy, or that there is a single simple answer. I think we had already worked out that the best route for negotiating a complex roundabout on a bicycle was the same as the one that other vehicles use. At my current level of expertise, my new lessons are that I should show more clearly that I intend to maintain control of the lane, and I must resist the temptation to keep out of everyone's way by heading for the kerb. I could also do with practising techniques for negotiating with drivers for access to a lane, and in handling complex manouvres at speed. I don't really get how to use other vehicles as a shield, but I will leave this for another day.

Finally, thanks to everyone who has been joining in, particularly "disgruntled" who prompted me to try and set this down without losing any of John Franklin's clarity. I hope it makes some kind of sense.


disgruntled said...

Thanks! I do find multi-lane roundabouts very intimidating and they are where I've had most of my near misses. Fortunately I can avoid them most of the time, which for me is probably still the answer...

Must go and get my own copy, clearly.

Paul said...

Back in the day when I used to do more cycling , my guide was 'Richards Bicycle Book' dated 1983. This gives similar advice, though he does say that the law requires cyclists to "ride to the left of the left lane as far as is consistent with safety". As he comments, an 'elastic definition'. In traffic I usually did as you have described and rode in the middle of the same lane a car would use. The result could be a grumpy driver but better that than one squeezing past 6 inches away. I think the factor here is your own speed; if you are doing a similar speed to the traffic you can get away with occupying a slot in the lane, if you are much slower than the traffic they will get cross.

Gregory Marler said...

I've been very interested following your posts about roundabouts.
I think it comes down to, if I don't know the roundabout well enough I should get off the road and go over pedestrian crossings. If I know the roundabout layout & traffic flow, I can be confident in the route I want to take and I can straddle my lane (ride in the centre) to not let any unthoughtful motorists shrink my space from the traffic.
It's when I don't know the roundabout, or where I'm going, that on the roundabout I may change my mind about the lane I want, the switching between lanes is bad.
It's nice when there is a cyclists area at the front of traffic lights, so I can see the roundabout and think what to do.

I think I use vehicles, at least at normal T-junctions. Imagine waiting at a junction where you have to give way. You and some vehicle (a long bus can be nice) are waiting for a gap to go. The bus is less scared of being knocked over so can go out first, turning right. Now the busy traffic in both directions has had to stop or slow down. You are free to go straight on or left and get going on the busy road.

gom1 said...

Thanks for the comment Gregory. It certainly makes sense to to attempt a roundabout when you don't know which exit you are aiming for. The whole exercise is quite difficult enough when you do know where you are heading.
Your technique of using a bus as a shield makes a lot of sense. I guess that when there is a long wait, a cyclist can't really "force" their way into a stream of traffic, but a large vehicle can. And the larger it is, the more likely that a cyclist can match their speed during the manouvre.