Changes

This is good option for Karlovy Vary direction. Take tram 22 to ''Bílá Hora''. Walk 50m west along Karlovarská street to past the red/white railings and there is a quite good place to hitch-hike.

Take metro line A (green) to ''Hradčanská''. Then take bus [http://www.tram-bus.cz/stredni-cechy/autobusy/linka-310610 310610] or [http://www.tram-bus.cz/stredni-cechy/autobusy/linka-310082 310082 (B82)] from bus-stop ''Praha-Hradčanská'' and get off at ''Velká Dobrá, u skoly''. Follow the direction of the bus and turn first left (Unhošťská street), than second right (Lesní street) and after 200m you should see the highway and the petrol station on your right.<br/ >If This option is good if you prefer petrol stations, try this option, although it is quite far (30 km from Prague centre).