Imitating a car on Google maps, which arbitrarily decide where to go (no addressee)

I would be very glad if someone could help me with this. I am planning to write a script that simulates a moving car on google maps. just a marker that moves along the roads. The point is that it has to move and turn erratically on the roads, I mean without a final destination. he must simply need a starting point and decide for himself where he should turn.

here for example it navigates to its destination: http://econym.org.uk/gmap/example_cartrip.htm

I only need to give it one spot and it starts to move and rotate randomly and continuously.

- it's possible. and how can i do it. I would really appreciate it if I could get an edge.

PS: at the same time, I need to store every engine coordinated in the database.