Moving inexorably into cities with the quiet determination of a B-movie blob, advance stop lines (or ASLs) have at once become a visible sign of a shift in importance of the cyclist, and a source of confusion for drivers and riders alike.

The rule for drivers is fairly straightforward - stay out of them. Although this isn't entirely accurate. If a light turns red and a car has not yet passed the first solid white line before the ASL then yes, he should stay out, but if the light turns red while in the ASL legally the driver has to stop before crossing the second white line at the head of the ASL. Worth bearing in mind next time you're about to berate a driver for encroaching into our space, he might have just got caught there and was actually obeying the letter of the law.

So what of cyclists? Well actually, if there isn't a feeder cycle lane into the ASL then the same rule applies, meaning you cannot actually pass traffic on the left or the right to move into the ASL. Conversely, if there is a feeder lane then you have every right to use it and move into the ASL. Which brings us to the burning question, are they any use?

For turning left or going straight on you have to wonder - cyclists don't really need the help in these situations, unless you use the argument that ASLs at least make cyclists more visible, or makes the possibility of cyclists appear more freshly in the minds of motorists.

For turning right there are obvious advantages, with a rider being able to position himself at the head of the traffic without having to move through traffic in motion to the right hand side. Although this situation is itself fraught with problems as the option proves its worth only if the traffic has only just been stopped and the cyclist is almost at the ASL.

The cyclist has to make his way to the ASL using a feeder which is usually on the left. If the lights turn green at any time while he is on the left then moving to the right has suddenly become more difficult and dangerous, and he my have to wait for the next light sequence to make his turn. And the anti-cyclist opinion of many drivers is not going to be changed if they are held up by a bike mking its way to the right hand side of the ASL with the lights changing mid-manouevre.

Add to this the many cities which have decided that ASLs don't need to be painted red and suddenly it starts to look like we don't have something which improves the lot of cyclists at all. Is it enough that an ASL lets drivers know that there might be cyclists on the road? And do they actually do this?

Perhaps we shouldn't really criticise anything that is trying to help cyclists, but it's hard to actively support something which seems yet to deliver anything but a token gesture...