[OSM-talk] oneway=1

[Arieh Skliarouk]

Hello,

I think it is wrong to specify street direction explicitly, at least
for the long term. Street direction tend to change, and you don't want
OSM users to get tickets for going wrong way?

I am sure commercial mapping companies have some kind of agreement
with authorities regarding directions change. Until OSM has something
similar, we can't rely on this information to remain static.

Direction tags on roads wider than certain width, can be relied upon,
though. For narrow streets the direction needs to do deducted
statistically.

I see following algorithm as one that can work:

Initially, mark all narrow streets as having "questionable" direction,
with allowed direction of the one that submitter have travelled on it.

The client software (one that runs on PDA) needs to be able to notify
server that the car just passed the street in previously
known-forbidden direction. Once several similar-looking GPS-traces
from different users are received by server, the street direction can
be recalculated.

Similar way, server should deduct streets that have not seen certain
direction GPS-traces and mark the street as "questionable" direction.
PDA-client should notify the user about questionable status of the
street direction and allow clarification of the data by user, with
subsequent upload to the server.

Other factors that can change in lifetime of a street (off the top of my head):
* Whether only public transport is allowed
* Trucks are allowed only during certain hours
* Cars with dangerous cargo (explosives, fuel, etc) are not allowed
* road is under (re)construction, find another route
* Only certain maximum weight or height vehicles are allowed through
* Pedestrian only
* etc

What do you think?

-- 
Arieh