Originally Posted by
cyccommute
There are several reasons why filtering to the front on a left turn is a very bad idea. First, if the left turning lane of cars has to wait on a left turn signal or if there is no left turn signal and the cars have to wait for on-coming traffic to clear, as a cyclist you are trapped to the right of the first left turning car and next to a line of cars that is moving on your right. People don't expect you to be in that position and, if someone is less than attentive, you could end up as a smear on the right front quarter panel of the first car in line.
When answering OPs question I was thinking of the two significant stoplighted left-turns on my commute; one on the way to work, one on the way home. Both are large intersections with two dedicated left-turn lanes, and their own dedicated portions of the light cycle. So when rolling up to a red light, left-turning and straight-going cars are all stopped (it's a red light), and I filter up and move to the front of the crosswalk, about 8-10ft in front of the cars.
Second, cars that are turning left aren't expecting to see a vehicle making the same left turn on their right. Again, you aren't in a place where a turning vehicle expect to see you. If the motorist makes a wider than normal left turn, you could still end up as a smear on the right front quarter panel of the first car in line.
I think in these two cases, this actually helps me. Rolling right into view and waiting in the crosswalk would be startling to a stopped driver waiting at a red light, and I cannot fail to be noticed. When the left-turn signal goes green, cars are always very tentative, I get off the line quicker than they do (and am ahead of them in the crosswalk anyways), and I am almost never passed during the turn. And the intersections are quite wide, and left-turning traffic normally tends to cut tighter rather than wider (even without cyclists there), so I make an exaggeratedly wide turn, aiming for the bike lane, and feel I am never in danger from oncoming left-turners.
Additionally, a turning car might not see you and could make a right turn into a driveway as soon as they turn left. This is a left/right hook combination.
That's a good point; in the case of my two intersections, there is no right turn or driveway for at least 1/4 mile. But I think that if I had rolled to the front of the crosswalk, the startled driver would not suddenly forget I was there.
By queuing up in line, you are in control of the cars behind you. You aren't sitting exposed to moving traffic on your right and, contrary to what some seem to think you are less likely to be hit by a car moving behind you. You are also predictable and the cars know how to deal with your movement. An on-coming motorist won't be confused by your actions as they recognize that you are turning left.
Situations and particular intersections are all different. This morning I came to one of my stoplight left turns with timing such that the left-turn arrow went green as I was crossing to the left turn lane(s). I instantly recognized that, even though I maybe could have filtered with a burst of speed, the best course of action was to ride up behind the back stopped car and head into the intersection in turn.