Trigger when driving on the Landscape

Hello everyone !

There is something i’ve never done, i search on internet but find nothing…
I’m making a race game, i have a road made of staticmeshs, and i want the car to slow down if go out the road into the landscape.

So how to trigger an event if the car walk on the landscape ? To make the car slow, and also to add some visual effects etc.

Thank you a lot, i will also still look on internet, maybe i will find something, anyway if so i will post it here.

Thx !