Cycling and Risk Taking survey

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How exactly the crashes occurred is irrelevant to the importance of advising cyclists clearly not to go down the inside of a lorry, or that lorries can swing out to the right before making a sharp left turn. ...

This point worries me, as it seems to imply that these sharp turns are the most dangerous ones, and i'm not convinced.

Imagine a lorry going along a straight road a reasonable distance from the kerb then around a corner and onto another straight section, ending up again at a reasonable distance from the kerb. Follow the curve traced by the rear wheels. For the gap between the lorry's wheels and the kerb to close, the wheels have to follow a *gentler *curve than the kerb *. But pulling out to the right first allows lorries to turn their rear wheels *sharply *around corners. It's when the lorry *doesn't *pull right first that the gap closes without warning.

Given enough road space ahead and to their right, articulated lorries can turn their trailer wheels on the spot. These dramatic road-filling manoeuvres happen at lower speeds and present a hazard that is fairly obvious. **

Non articulated lorries do have geometric limits on the turn radius of their rear wheels, but these are often pretty small. For both types of lorry, the main reasons to take rear wheels around a gentler curve than the kerb are probably lack of road-space to the right, and speed - gentler turns can be taken faster.

I think a better warning would be:
[INDENT]As lorries turn, their rear wheels can close up to the kerb without warning, even while a gap remains at the front.[/INDENT]

*a sharp turn can close the gap if the lorry ends the turn next to the kerb.
**If you draw lots of diagrams following what all the wheels do, you see that when the lorry swings right first, the gap at the trailer wheels doesn't start to close until after the front of the lorry is obviously turning left.