That's right, even in the best case scenario (mapping them at their actual locations and expressing their impact on roads using relations), we'd still end up with approximated delays for routing which may be completely unrelated to the resulting, emerging traffic patterns. So mapping the lights at the intersection node, or just before at each entrance, or counting them twice or even thrice, that is all unlikely to have a significant impact on routing and just give birth to new "special cases" where the new "heuristic" didn't work.
However, using clever tricks is still better than nothing. If those tricks have some relation to the expected traffic patterns, the routes will be more like that of Google or Apple more often. And hey, no need for an Internet connection. I had a link (but lost it) to a system that was collecting traffic data and assigning it to the IDs of OSM's ways in its own local database. I could only find about Transiki now, which has shut down long ago. On Wed, Aug 28, 2013 at 3:20 PM, Bryce Nesbitt <bry...@obviously.com> wrote: > On Wed, Aug 28, 2013 at 7:57 AM, Fernando Trebien > <fernando.treb...@gmail.com> wrote: >> >> However, routing would double count traffic lights in two-way roads >> (as in Kytömaa's counting), though guessing the direction by proximity >> to the intersection should be accurate here in about 99% of the cases, >> as would be for stop signs. > > > The double (or triple) count of traffic signals is something the routers > need to model anyway. > As has been pointed out, traffic engineering practice is to synchronize such > lights. > Even in places that deliberately mis-time signals to reduce flow, three > intersection length signals > would be coordinated. > > We don't need to tag to the router! The simple intersection node tagging is > enough for good routing! > > (Google or Apple's routers have an advantage here: they don't have to count > signals as they > can count average travel time.) > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > http://lists.openstreetmap.org/listinfo/tagging > -- Fernando Trebien +55 (51) 9962-5409 "The speed of computer chips doubles every 18 months." (Moore's law) "The speed of software halves every 18 months." (Gates' law) _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging
