I'm undecided they are not required on either of my trucks but the incident recently of the newly restored duesenberg being broadsided by an SUV got me thinking about it. Wiht my vehicles it has nothing to do with diminishing the value of the trucks as I don't see my trucks as being extremely valuble other thaan to myself. Just wonder whether or not installing them in a vehicle not designed for safety belts would make any difference. I do wear them in vehicles that are equiped with the safety belts.