Used them in the bigger trucks all the time when I was towing. I do not see the need in a smaller vehicle unless you were towing a trailer that was bigger than the mirrors are wide. Mostly just made it more comfortable to lean forward and check blind spots in the mirrors. Supposedly they will release and allow the belts to lock in a collision, but you would go forward the 5-7inches in an impact and likely break your collarbone. In a big truck, where the mass of the truck is not likely to produce the same impact on the driver, they are relatively safe. I would imagine in a small vehicle it could cause some more serious injury. Just my $.02