streets and bus stops

Hello people !

I want to ask you about an idea I have in mind.

The problem:

I live in a very large city (Buenos Aires, Argentina) that has several
kinds of public transport services (bus, urban train, subways) that
connects several points of the city.
But: when you are new to the city is very difficult to move from one
place to another using this services (and finding what combinations of
them are optimal).

Possible solution:
Develop a web service that finds the optimal way (and alternatives)
between two addresses in the city, using public transport.
Thar service will be avilable using web browsers and also SMS from
cell phones (very usefull I think)

The question:

Is there a way to describe city streets and addresses, street intersections, and bus stops ?
I found tha certain nodes belong to more than one street, but not all intersections are listed. Is that just a coincidence ? or all the cross roads must have common nodes ?

Regars.

Emilio Norrmann

I think this page will help you to get up to speed with routes, relations etc.

If two roads really intersect (they ‘touch’ each other) then they should have one (or more) common node where they intersect. But if they cross using a tunnel, flyover, bridge etc. then the two roads should not have a common node.