It's not using the google API for "shortest driving distance".
From the about page (
http://ridesf.com/about):
"The site backend is powered by
Postgres with the
PostGIS extension and the routing is found with the
pgRouting extension.
A small C cgi app returns the path in a variety of formats (
GPX,
KML,
JML,
WKT, &
JSON).
The data for the bike lanes is a combined version of data from the
CA MTC and
Tiger Line Data from the US Census.
The route is displayed using the
Google Maps API."
It is mostly useless right now since I don't have a conflated data set that includes bike lanes and non bike lanes. It really is just a work in progress/hobby.
John