[Talk-GB] Classification of roads

[Mark Goodge]

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