[Talk-GB] Where do speed signs take effect (from Changing "stub" cycleways to pavements)

[Jass Kurn]

I didn't spot this email thread diverge from the main one about cycle
tracks, and added some info there that would be better placed here.

>From my knowledge I strongly agree with what has been written by Mark
Goodge regarding the combined impact of signage and TRO. But it is worth
alos noting that statutory guidance on location of speed signs is provided
in Traffic Signs Manual (Chapter 3). Signs are allowed to be up to 20m back
from the edge of the main carriageway. The guidance states it is up to the
highways authority to decide if this short stretch impacted by the sign is
significant enough to have a seperate speed limit traffic order.

Jass

On Tue, 15 Feb 2022 at 10:06, Mark Goodge <mark at good-stuff.co.uk> wrote:

>
>
> On 15/02/2022 06:55, Tom Crocker wrote:
>
> > Hi DaveF, I'm intrigued. I thought the large speed sign did mark the
> > point of the change in legal speed limit, although of course approaching
> > the junction it wouldn't actually be safe to travel at that speed. I
> > remember the teacher on my speed awareness course (oops) making a
> > similar point and "Know your traffic signs" [1] seems to say this. Am I
> > missing something?
>
> This is one of those situations where there is no single "right" answer,
> because, like a lot of legal matters, the law allows for a certain
> amount of pragmatic fuzziness in implementation.
>
> Any deviation from the national default speed limit requires that the
> new limit is imposed by a Traffic Regulation Order (TRO). But a TRO is
> not in force unless indicated by signs. That is, both a TRO and signage
> are necessary conditions for an enforceable speed limit, but neither
> alone is sufficient. If there is a TRO but no signs, then the TRO has no
> effect. If there are signs but no TRO, then the signs have no effect.
>
> In cases like the Hood Lane 20mph limit, it's normal for the TRO to be
> applied to the entire street - the actual wording will usually just name
> the street and its classification number. But the signs will be erected
> at a point where it is most convenient or appropriate to do so, which
> may not be right at the end of the street.
>
> What that means in practice is that the enforceable speed limit - the
> stretch on which you could be ticketed for doing 25mph by a policeman
> with a speed camera - starts and finishes at the signs. But the TRO
> imposing the limit will cover the whole street. It just won't be in
> force at the stubs at each end.
>
> How you map this is, therefore, a matter of interpretation. One option
> would be to map the limit as only being between the signs. If you were
> mapping a speed limit change on a continuous road - eg, where a road
> crosses the boundary of an urban area - then you would certainly map the
> change as being precisely where the signs are. But where the limit
> change is associated with a junction (as here, at Hood Lane), and it
> just so happens that the signs are set back slightly from the junction,
> then, in practical terms, it may well make more sense to map the limit
> as extending to the junction because that's more useful to consumers of
> the map. Even though that short stretch between the junction and the
> signs does not have an enforceable 20mph limit, the reality is that
> nobody is going to be going that fast anyway at that point and having a
> short stretch mapped as 30mph is liable to confuse things like sat-navs
> which include speed limits in their data.
>
> So, in this particular case and others like it, I would tag the entire
> street as having a 20mph limit. That's not necessarily the most
> pedantically correct option, but it is the one which is most appropriate
> for the on-the-ground conditions. And, while OSM not in any way obliged
> to follow the conventions used by other mapping agencies, most of those
> which use speed limit data (eg, sat-nav map providers) would tag the
> entire street as having a 20mph limit here.
>
> Mark
>
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