Those runaway truck lanes that exist on the side of some highways may look like a waste of space, but there's a good reason why they are completely necessary. Trucks, just like all vehicles, have braking systems. Given their much more significant payloads, their braking system are also much more substantial. However, when that system fails (perhaps with very little warning), it takes a lot more energy to bring a tractor trailer to a complete stop compared to a passenger car. This is where runaway lanes, truck arrester bed, emergency escape ramp, or whatever you call it, comes into play.
In the case of this Mexican runaway truck, it had lost its brakes for a good amount of time before the police finally came to provide escort. Thankfully, the driver was able to navigate the downhill sections of the highway well, and that there weren't too many motorists on the road. The truck, at some point, reached speeds of 100 mph according to the video's description. When it finally came upon a runaway lane, we can see how the gravel filled arrester bed was able to bring the massive truck to a complete stop. Luckily, the driver escaped unscathed.