Objects falling through surface that they shouldn't fall through

Here are the physics and collision settings for the road piece that the front of the van is sinking into:

1st Surface Collision

Here are the physics and collision settings for the road piece that the back of the van is staying on:

2nd Surface Collision

Here are the physics and collision settings for the van’s body:

The van’s wheels have separate physics and collision settings, which are the same for each wheel: