Just then the lead car suddenly flies into the air and off the road.  The same thing happens to the
second escort car.  Finally, the truck itself is mysteriously lifted off the ground and dropped.

A crew moves in, rips the fallen truck apart and claims the cargo: Doctor Franklin Hall.

(The attackers had been using the doctor's own Gravitonium technology to distort gravity.)

As you might guess, this wasn't filmed in Colorado.

It was actually shot on the Old Golden State Highway, in Castaic, CA

It's called the "Old" Golden State highway because it runs next to the modern
Golden State I-5 freeway that replaced it. Both cut a swath through the
Castaic mountains, on a route that links Los Angeles with the cities to the north.

Castaic is about 56 miles northwest of downtown Los Angeles,
and about 7 miles north of Six Flags Magic Mountain.

This scene was shot on the stretch of the old highway from the 5 Freeway
north to Pyramid Lake, with the bus is headed northwest.

Here is a matching Google StreetView of the road.