FosseWay wrote: ↑Mon Jun 14, 2021 13:57
... There are a number of issues with mandating that drivers must leave the roundabout in the right-hand of two available lanes after turning right.
It's not
mandated in AU. Perhaps I should have said that the video 'advises'.
Some of them admittedly may be more likely to be an issue in the UK than Australia given the tendency towards broader roads with more room in all directions in Aus.
I don't think so. The issues are the same. While your suggested 'tendency' is somewhat true, our road dimensions, lane widths, etc, are the same.
1. In the case of the green car in the HC example above, it shouldn't matter which exit lane it takes because there shouldn't be anything alongside once it's passed the straight-on exit.
If lane usage custom permits, why shouldn't there be? This is
part of my point. A car that enters alongside another would know or first determine which exit the approaching car is aiming for and whether it's going to exit in the right lane. It would then either proceed, with caution, or wait.
People shouldn't be turning right from the left lane.
We
don't turn right from the left lane.
and people shouldn't be setting off from the left arm at the same time as someone already on the roundabout is still passing the entrance.
The main point of my post is that, with consistent lane discipline, it is possible for such setting-off to be safe. The vehicles travel side-by-side, and merge after exit if applicable.
3. Urban areas in Britain are often not particularly planned, with several turns in quick succession. It's entirely possible for there to be a left turn a few tens of metres after the right-hand exit from that roundabout, and if you want to take that exit, you need to be in the left lane. The requirement to position yourself in good time for your intended manoeuvre doesn't suddenly not apply just because the stretch of road immediately before your turn happens to include a roundabout. As I say, this kind of crowded layout may be less of an issue in Australia.
You have an idealised image of AU's urban roads! I can assure you that most of the peculiar configurations that you encounter in the UK do also occur in Australia. Our
inner urban areas are old and fairly dense.
4. I'm not aware that there is a concerted tendency to tell people on the approach to a roundabout how many lanes the exit has, especially exits other than the main line (usually straight on). In other words, a driver approaching the roundabout to turn right won't know how many lanes there are on the exit road till they see it, after passing the straight ahead exit.
This is so in AU too, although we don't have giant roundabouts so there is better overall visibility.
A related point is that there are plenty of roundabouts with two lanes, where less major exits off them only have one. This rule then essentially requires them to exit the roundabout from the outside lane, which I would have thought is contrary to both the HC and common sense.
Road markings and signage specific to each roundabout and common sense take care of both these issues, as in the UK. And it's not a "rule".