It can be dangerous. I always try to get past trucks as quickly as possible. The following is a summary from a MythBusters show, and can be found at
http://kwc.org/mythbusters/2007/06/episode_80_big_rig_myths.html
Exploding Tire of Death
Myth: A tire blowout from a big rig can decapitate a person in an adjacent vehicle
Setup
They couldn't find anyone to let them do a tire blowout on top of their
dynamometer, so they decided to build one of their own out in a field. They chopped the bed off of a pickup truck and sunk it into the ground. The big rig was lifted so that it's rear tires were on top of the pickup truck's tires. This allowed them to spin the wheels of the big rig by accelerating the pickup truck, while a forklift allowed them to control how much weight the big rig placed on the pickup.
Buster was setup on a motorcycle adjacent to the tire.
Big rig tests
- Shotgun test: They used a .12 gauge shotgun with a deer slug to blow out the big rig tire. Jamie hit the tire, but they didn't get the catastrophic tire failure that they wanted -- all they got was a "hisssss."
- Flexing test: They tried to use a combination of high heat and low pressure to get the tire to blowout. "Flexing" is responsible for most big rig highway blowouts: the low pressure and high heat make the rubber wobble. They inflated the tire to 30psi (1/4 normal pressure) and heated the tire. They were able to easily get the tire to 150 degrees, but they couldn't reach the 350 degrees failure zone. To get the tire to burst, they hooked it up to a pump and tried to suddenly over-pressurize it. The over-pressurization gave Buster a gust of wind as a hole ripped opened up in the sidewall, but not much more.
- Shrapnel test: They weren't going to get the catastrophic failure they wanted, so they decided to spin up the already popped tire up to speed to see what would happen. Rubber shrapnel and smoke came flying off in every direction, except the direction of Buster. They did get valuable data, though, on the rubber shrapnel.
Rubber chucker test
They had trouble controlling where the rubber flew in their tests, so they decided to build their own rubber chucker to fling the chunks of rubber at Buster's head. They had video of the flying debris from the previous test, so they could tune the size and speed of the chunks to be accurate.
The rubber chucker was actually very similar to their previous test rig. They placed the pickup truck on top of a trailer, wheel to wheel. Much like a pitching machine in a batting cage or on a tennis court, the spinning wheels grab anything placed between them and fling them at the target. In a test fling, they easily shot a piece of rubber at 40mph through a wooden board.
They replaced buster with a ballistics gel head that they cast around a spine. The head was stuck behind a car door window in the path of the rubber chucker. In the first shot the ballistics gel head was decapitated -- the spine they stuck inside was sticking out.
confirmed
