Thursday, March 23, 2006

Dithering

I had a dithering motorist this morning. As I approached a red light, he was overtaking. First, he decided to follow me to the intersection, and then make a right turn. On second thought, he figured he could go around me to the left, then make an abrupt right – the classic ‘right hook’ maneuver. But on third thought, he discovered that I was going faster than he’d realized, and the safe thing to do was to follow me and turn right.

I’d watched his approach in the mirror, dodging right-left-right as his thought processes kicked in. I rode more or less in the middle of the right-hand lane, just to the left of the tire track. That’s the usual position when I go through an intersection. It makes me a little more visible to a motorist on the cross street, and gives me a little more room to maneuver.

Dithering can be dangerous. At 45 miles per hour, a car moves 66 feet per second. While he hesitated, this morning’s driver rapidly closed the gap between us. Each instant that he spent deciding what to do allowed him to get ever closer, shortening the time he had to react. Dithering cost him precious time and distance.

This is one of the reasons that lane positioning is so important. When a cyclist rides in the right hand tire track or even further to the left, he makes that decision easier for the overtaking driver. Motorists are very good at avoiding things right in front of them, but when they have to judge whether there’s sufficient clearance to the right, they’ll dither and sometimes pass right next to our elbows.
The problem may be compounded by the multi-tasking necessary when driving. A motorist has to watch the cyclist, try to judge the traffic light, check for other cross traffic, check for pedestrians, look for potholes and debris, etc. It really is asking a lot when someone is moving that fast.

But cyclists are faced with dithering too. There’s been a discussion on the LCI of passing in the door zone when traffic is moving very slowly or is stopped altogether. The question was whether it’s a good idea to teach students how to do this safely, or whether to advise them to avoid the door zone at any time.

The supposition was that traffic was moving very slowly or was stopped, and there was space to filter forward to the right of the traffic lane. Done carefully and slowly, it’s possible to ride there. But it introduces many of the same problems that dithering motorist encountered. A cyclist riding in the door zone, even riding slowly, has to watch for people exiting cars on both sides. He has to watch for jaywalkers, debris, cars pulling out or pulling in, and even the occasional wrong-way cyclist. He has to be aware of not only the road conditions and traffic lights, but now he has to gauge the intentions of people inside automobiles. And if he’s going fast he encounters the same problem with shortened reaction time.

Worse, when traffic starts moving again, he has a hard time merging left into the traffic lane. Now, there may be a grade school mentality at work here, as many people resent someone ‘cutting in line’ ahead of them. Motorists in this situation find it very easy to tailgate the car ahead, and prevent that pesky cyclist from moving back over to the left.

My advice is to avoid the door zone at all times. It’s much less complicated.

2 Comments:

Blogger Fritz said...

This undecided "dithering" is also why I don't take the right of way when it's not mine, even if the motorist yields it.

This morning, for example, I signaled a left turn, moved left in my lane and stopped, waiting for oncoming traffic to clear the intersection. The first car in the oncoming lane stopped and waved me through. I shook my noggin "no" (exaggerating the movement so it would be clear through the falling snow this morning) and, after a moment's hesitation, the motorist continued through.

*IF* I had gone through the intersection, likely as not the motorist would have changed her mind and proceeded through. If she clipped me, the fault would have been all mine. I think it's best for everyone to follow the normal rules of the road rather than make things up along the way just for convenience sake.

10:46 AM  
Blogger Fritz said...

Oh, in the situation you describe of slow traffic alongside parallel-parked cars, I squeeze right into the traffic and take the MIDDLE of the lane. There are a couple of spots on my commute where this occurs almost every evening. If I split lanes it's because I'm moving over for a left turn.

I admit to sometimes slowly filtering on the right when traffic is at a standstill -- occasionally somebody will see me and scoot right to cut me off, so I just pass them on the left before cutting back to the right. Juvenile stuff.

10:50 AM  

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