They ask if you want to purchase the script that allows it to run on the roads that you mentioned. (That script cost's L100 I believe ). I think they are fun and the person that makes them has the outlook that they are improving everyones SL Experiance . However i do see piles of them all over the mainland contenents and I've always wondered how the owners feel about them maxing thier prim counts for them. They will push ,but they always say "Sorry" . The tank one is a bit scary as it is scripted to shoot temporary prim bullets at whoever touches the tank prim.
I have actually ridden on them and bought a couplle out of curiousity. They don't go "where you want" like some SL Vehicles will because the script tracks on the road prims . They will turn around if touched on the rear decklid. I have travled for over an hour with not much problem except whemn crossing multiple simlines on the diagonal trajectory . That is also where you will see a few piled in a heap on someones land or "Abandoned Land Parcels". On those parcels , nobody clears the prims so they get a lot of junk prims wasting resources. I think that is one of the biggest drawbacks to these "Road Tracking Vehicles" :smileyhappy: