On 27/06/2018 16:01, David Woolley wrote: > On 27/06/18 15:30, SK53 wrote: >> # Junctions with islands which also cause a single carriageway to >> split and merge around the junction. >> # > > I would definitely agree that this is tagging for the renderer, and > wrong. > > However, I can think of a case like this where you might well get > attention from the police, for a dangerous manoeuvre, if you U-turned > at any time but the early hours. I seem to remember that one of the > routers thinks this is a good place for a U-turn. > > Obviously the correct thing is for routers to use a heuristic to > detect that if two one way roads join at a very acute angle, they > shouldn't route from one to the other, or should give it a large > penalty, but it does beg the question as to whether OSM should allow > router hints. > > The problem with hints is that, like "too dangerous for cycles, so > mark as no cycling" they are subjective, and the router should really > be looking at the topology to infer a that this is really a dual > carriageway.
Where there really is a no U-turn sign (and consequently an offence contrary to s. 36 RTA 1988 for failure to comply), might it help to tag it with traffic_sign=GB:614 (see Schedule 3 to TSRGD 2016, <http://www.legislation.gov.uk/uksi/2016/362/schedule/3/made>)? This wouldn't do anything to help routing algorithms, but might make it a little easier for mappers to find potentially spurious restrictions to re-survey. _______________________________________________ Talk-GB mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-gb
