[Talk-GB] Classification of roads

[Jez Nicholson]

So, I assume that routers give weights to the road classification....are we
in danger of people trying to discourage rat runs by downgrading the road
classification in OSM?

On Thu, 19 Aug 2021, 22:59 Mark Goodge, <mark at good-stuff.co.uk> wrote:

>
>
> On 19/08/2021 20:40, Martin Wynne wrote:
> > Does the presence/absence of a white line down the middle have any
> > bearing on this? How about the height of the street lamps? The width of
> > metalling?
>
> Not really, no. Centre markings, as a general rule, are only found on
> classified roads, so their absence won't help you tell the difference
> between tertiary and residential as neither will normally have centre
> markings (although there are exceptions, in both cases). Similarly, the
> width of the road is more a function of when it was built than its
> status. And street lights are whatever height was appropriate when they
> were installed.
>
> What can be useful is the presence or absence of "give way" signs and
> markings at the end of a street where it ends in a T-junction with a
> road of higher priority. These are recommended (but not mandatory) at
> the end of tertiary roads (what the Traffic Signs Manual calls "minor
> roads") but not recommended at the end of local or residential roads.
> This, for example, is the end of a minor (tertiary) road:
>
> https://goo.gl/maps/9VETh4KKHWu8yVR97
>
> but this is the end of a residential road:
>
> https://goo.gl/maps/xSRQrJUtgDPEo3ZJ8
>
> So, while their presence or absence isn't definitive, they are often a
> good indicator of whether the local authority considers the road to be
> tertiary or residential. The biggest problem there, though, is that a
> lot of urban roads end in light-controlled junctions or have stop signs
> rather than give way signs (and stop signs are always mandatory where
> the circumstances require their use, even on local roads), so looking
> for give way signs can be a fruitless task in some places.
>
> Mark
>
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