Oh! Volcanoes. Movies volcanoes are bound to emit both pyroclastic flows AND liquid lava flows. In real life it's either/or. You can have a safe, non-explosive Hawaiian type volcano with it's pretty glowing red lava, or you can have an Andesitic type volcano which creates a massive boom and great clouds of ash but very little in the way of lava flow.

You're not going to outrun a pyroclastic cloud. You're not even gonna beat it if you're driving.
Your car will not drive over lava unscathed.

Dante's Peak has a lot to answer for.