On Fri, Mar 26, 2010 at 5:47 PM, Nic Roets <nro...@gmail.com> wrote: > On Fri, Mar 26, 2010 at 6:00 PM, Marcus Wolschon > <marcus.wolsc...@googlemail.com> wrote: >> Expected, general travel times and delays due to random events >> are 2 different problems. > > The two problems are so closely interlinked it makes sense to treat them as > one.
No. One requires statistical data of all of the road-network indexed by the specific road to make predictions about the infuence of this specific piece of road compared to the average road of that kind. The second requires statistical data of popular incidents that can happen everywhere and have such a large impact that the specific road does not matter. A 5Km trafic jam on a motorway of 2 lanes getting narrowed down to 1 lane will have the same impact no matter what the name of the specific motorway is. >> That there was a car accident last week does not affect the estimate >> of how long you are likely to travel by the time you react the start of >> a segment now. > > Of course it does ! How so? There IS no car-accident now and it is unrealistic to assume that there will be by the time you get there. Don´t mistake the average travel time with the statistical expected value for a single, random drive. > You have to account for the probability that the > road is poorly designed at that spot. I don´t think that the road has anything to do with it. To account for the probability you have to 1) detect an instance of a specific type of event 2) know the probability I don´t think 1 is possible with this kind of data. And I don´t think we´ll have the number of tracks for 2 in any meaningful number of places to merit development time. (Remember, we are short of developers everywhere in this project.) >> The most likely source of information about short time traffic obstructions >> is TMC and it usually tells you the expected delay. So this needs different >> issue not be addressed now and certainly not here. _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
