Does the amount of munitions or fuel in a vehicle affect the damage radius of such a vehicle's explosion?

Yes, says Ondrej Spanel, BIS' Lead Programmer. The more fuel and/or munitions laden a vehicle is when it is destroyed, the greater the radius of damage from the ensuing explosion. The same holds true for ammo crates. An exploding empty ammo crate will minimally impact its surroundings compared to an ammo crate full of LAWs, satchels or other munitions.