Dirt is flying! Narrator: If you've driven any one of the many highways crisscrossing the world, chances are you've seen one of these: a truck escape ramp. Some escape ramps slope upwards.

They're called runaway truck ramps, and they're designed to prevent extremely severe accidents in the event of brake failure. But who exactly are these ramps designed to protect, and how do they work?

DALLAS — The ramp from northbound I-35 to eastbound 635 in northwest Dallas has reopened after an overturned semi-truck jammed traffic Tuesday late afternoon and evening. Traffic was diverted ...