[Robo]

Originally Posted by Dorian Gray As a Vespa rider, I've noticed people do this to me every time I get on a fast (e.g. 50+ mph) road. It's not just your mum. I've therefore given it some thought. It seems that I vary my speed a lot, and so do other motorcyclists and scooterists. This is a consequence of the physics of riding a light and very un-aerodynamic vehicle at high speed. If I reduce power a bit for one reason or another, the speed decays much quicker on my Vespa than in a car, because I weigh one-fifth of a car but have more than half as much aerodynamic drag. The car behind me, meanwhile, is relatively heavy and aerodynamic, so variations in power (from accelerator pedal adjustments) are smoothed out. Since realising this, I've made a conscious effort to keep my speed even on fast roads, by paying close attention to the speedometer when I adjust my position on the scooter. And sure enough, cars tend to stay at a more predictable distance behind me (there are still many exceptions, since this is France, after all).

I get that that's part of it, but my mom does this tailgate/back off/tailgate cycle with cars, too. She's basically just not ever in control of her driving; it's all totally driven (ha!) by what mood she is in, and her moods swing wildly from one minute to the next.

I probably could have stopped by just saying that she's just not ever in control of herself. But that's depressing!

Originally Posted by Majost I think it's also that people simply aren't used to judging space behind motorcycles. I know I use cues from the bumper and rear tires on cars to help determine my distance (like how far underneath a car I can see, based on my angle). Those cues simply aren't there (or are very different) on motorcycles. I recognize this and adjust. I think many are oblivious to how things like that affect our perception.

When you learn to ride a bike the first thing anyone tells you is that drivers will always think that you're farther away than you are, simply because you're smaller and car drivers expect everything to be car-sized; thus a smaller vehicle subconsciously registers as not "motorcycle" but "distant car," even if the driver can see that it's a motorcycle. The other day my mom was waiting to perform a turn-across-traffic maneuver and she said "I suppose I could have gone in front of that motorcycle" and I told her point blank "No, you couldn't have."

I didn't include this in my list of grievances because it's an error in judgement that even many observant car drivers subconsciously make, and it was unrelated to my general thesis of her being an unobservant, irresponsible driver.