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Comment by oneeyedpigeon | Hacker News Reader

They should reduce the speed limit on that roundabout. Actually, they should reduce the speed limit on all roundabouts...

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Roundabouts don't really need speed limit changes, because they're naturally self-limiting. Most roundabouts have the same limit as roads they're on, so there are lots of roundabouts that have 70 limits on, say, dual carriageways [1]. But that doesn't mean you drive on them at 70.

Speed limits aren't really a speed that it's safe to go at throughout the limited area (for example, a blind T junction is probably unsafe at 20mph, but can still be in a 50). It's a speed that it's not safe to exceed, even when the road conditions appear to suggest otherwise. On a roundabout, as at other junctions without priority, the road dictates the speed, not the signage. Exceeding the safe speed indicted by the road itself is still an offense of dangerous driving, even if below the posted limit.

[1]: For cars; HGVs and vans both have a lower limit on dual carriageways. Not that many van drivers appear to know that.

Seems to be big enough to handle 30-40 km/h, but hard to judge from just the pictures. Obviously depending on the amount of traffic, the suitable speed might be lower/higher. Is the speed limit higher than that?

I just meant for safety reasons. Not just for the rabbits themselves — although I DO care about them! — but also for drivers who may be distracted by a rabbit suddenly running across the road.

The actual speed limit on that roundabout is an interesting issue! It's debatable, but the most accurate 'guidance' I can find is that it should be the speed of the majority of the approach roads — how you're supposed to work that out, sat in your own approach road, I don't know. The one in question is almost certainly 30-40 mph, which is about 50-65 km/h. In theory, some roundabouts have a 70mph speed limit, although they'll be very different from the one in question.

Disclaimer: UK driver, detest roundabouts.

I can't speak for that specific roundabout, but in my experience if various approach roads have different limits then they'll typically have signs changing them to match shortly before entering the roundabout.

So the speed limit on the roundabout is the limit on the road by which you entered, but note that it may have changed immediately before entering.

In this particular case, I'd assume the limit is 30 mph: it's in a built-up area with street lighting, and a quick look on StreetView doesn't seem to show any signage indicating otherwise.

(Pretty sure that on some larger roundabouts, e.g. on a 40 mph road, I've occasionally seen the small speed-limit reminder signs, but I don't recall ever seeing an actual change within a roundabout.)

Source: UK driver, much prefer roundabouts to most alternatives. :)

Seems like it would be a pointless expense having to post new speed limit signage on the entrance and exit when (well designed) roundabouts naturally cause cars to slow to appropriate speeds.

A distracted driver is going to cause an accident no matter the speed limit.

Disclaimer: UK driver, love roundabouts.

Distracted drivers don't notice speed limit signs anyway. They'll do 25mph in 20, 30 and 40 mph roads.

If they're like the daft old bastards around here they'll do 37mph in 20, 30 and 40mph roads.

In 3rd.

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