Arrester Beds
An arrester bed is defined by Arizona DOT as "a
gravel-filled ramp adjacent to the road that uses rolling resistance to stop the
vehicle". This rolling resistance is the stopping force. 
Hawthorn, Billy. "Runaway Truck Ramp East of Asheville, NC." Wikipedia. Wikimedia Foundation, 23 July 2012. Web. 18 Apr. 2017.
The Physics
Rolling friction plays the biggest role in stopping the truck. The sand provides a large amount of resistance to the tires. According to the website, Engineering Toolbox, the rolling friction coefficient of car tires on loose sand is roughly 0.2-0.4. This is as much as 20 times the rolling friction of car tires on asphalt pavement.
The equation for the force of rolling friction is:
