New project - complete the A road network

The nights are closing in and the weather’s getting lousy… cycle mapping after work isn’t such an appealing option right now. So here’s a mapping project where you can survey with the heater on.

The aim is to complete all inter-urban and rural A roads in Britain: that is, all A roads apart from those solely within towns.

OSM’s A road coverage has been increasing steadily, but haphazardly, over the last year. Some counties are now complete (Rutland and the Isle of Wight, obviously!), and some are almost complete: after a day’s work yesterday, I reckon there’s now only about three miles of unsurveyed A road in Oxfordshire.

So now’s the time to finish the job.

A complete A-road network will vastly improve OSM’s usefulness for routing; it’ll make the Mapnik and Osmarender layers look complete at higher zoom levels; it could even be used for a road atlas or for any maps that require a general-purpose road background. And we’re not actually that far off being able to achieve it.

The principle’s simple: add any missing roads you know of to the wiki page. Then either go out and map them, or (more environmentally friendly option (: ) print out the wiki page and take a detour next time you’re passing. You can, of course, use NPE and all the usual tools to help.

(And remember: green signs, highway=trunk; black-and-white signs, highway=primary!)


Most of the A roads in the centre of the country are done, it’s out to the edges where there are the majority of missing ones, as people don’t ‘pass through’ so often.

Green signs mark the primary network. So primary=trunk! Not particularly intuitive but people can learn. All I can say, is that I hope people can additionally tag maintenance= or something to similar effect, so that if people wish, they can extract trunk roads from the primary road network. It gets slightly irritating when people say there is no use for it based on there own interest in it. It’s not so important how 1 thing is tagged, but rather that 2 different things can be split apart if people want to. I resent this ability being denied by OSM’s tagging. Coincidently I was asked a couple of weeks ago by a geography lecturer if I could print off an image of the trunk network, and I can’t.

Personally from a graphical perspective I like the idea of having low zoom maps only display the main trunk routes (HA-Private managed). Google is very cluttered with green for example, and the fastest route isn’t clear. I’m sure there are exceptions, but in the vast majority of instances when you travel large distances around the UK you would stick to the trunk roads (HA-pri…), and getting onto a green signed road that isn’t HA will slow you down. Google’s route planner seems to stick to the Trunk roads though (although this may be from additional factors such as lanes=), so the problem is only really apparent when you only print off a map, and don’t know what road is what.

Anyway, it’s up to people rendering how they want it. It’s not up to OSM to decide for them. We should tag it how it is, not just how some want it to be.

On another note: Is the wiki page on trunk roads up to date? I would be interested to see what percentage of the trunk network, the primary road network, and the entire A road network is complete. We must be pretty close on the first 2?

Yes, I think the outer edges (Wales/southwest/East Anglia/Northumberland/Highlands) are going to be the difficult bit - though correspondingly they should be easier to get from NPE.

On the HA stuff, yes, I don’t see any reason why we shouldn’t have a “maintenance=” tag (or similar). I guess this might even be something where relations could be used. But as ever it’s probably not realistic to expect the original mapper to get all the information in one hit, especially as HA/strategic roads aren’t actually signed as such: will probably require someone who knows about these things to come back and tag the roads accordingly.

Wiki page on trunk roads is way out of date, AIUI. The wiki really needs some serious slash-and-burn editing. :wink:

Interesting that a number of people have said that finding the HA trunk road system and mapping it will be hard. The wiki links to the Highway Agencies web site, and lists the trunk roads based on the map that it used to link to on there. I have also seen signs that have HA written on them, and/or there are signs there solely to state that the road is HA managed. So for some roads gathering data is easy, but I imagine that source isn’t everywhere.

If this map is copyright (or we can’t even use it to find out what roads are trunk) then that link should be removed and the list also surely?

If we had a mapping event held on the broads, then that would sort out all the A roads left in east-Anglia I think. Assuming people came from quite a far.