[Routing] Crowdsourced costing

[Frederik Ramm]

Hi,

   all of us involved in routing are probably using more or less clever 
algorithms to compute the "cost" for traveling along a given road. My 
own experiements which focused on long-distance routing were quite 
simple and simply assigned an expected speed to each highway type.

However, this will only ever make us "as good as" existing routing 
solutions based on proprierary data: we will never become "better" than 
them (except perhaps the odd detail in our data that they haven't got).

What we should really aim for is to crowd-source the costing, i.e. to 
give mappers/users control of how likely a certain road will be selected 
for routing, and how high the penalty is for choosing to route across a 
given junction (at a given time of day with a given vehicle). There are 
so many things that locals know ("I would never choose that road on a 
Tuesday morning because you're more than likely to be stuck behind the 
garbage collection truck", or "that motorway is only 2% longer but much 
less likely to have snow", or simply "this is a primary road but the 
secondary that runs almost in parallel is usually quicker" and so on.

There's still some way to go until we achieve this. Perhaps we need to 
have a separate tagging scheme or maybe even a separate data base for 
such information, because it is perhaps a bit more volatile than 
standard OSM data, and it is also quite likely that those that collect
costing data are different from those collecting road geometries. But we 
should really aim for this - a data base where every road has some 
user-assigned cost would be ideal for routing, and computing the cost 
based on heuristics is always second-rate.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"