Maybe because there is no road system in the game or the game engine. You need a road system and it's programming to have usable vehicles in the game. What looks like roads is not roads it's paths - the programming is walking, teleporting, and fx pathing- nothing else. Should have been in the game first - not after the fact. They obviously had no thought of having vehicles of any kind in this game from the begging of settling on this design other wise they would have had usable pathing and roads - not paths made to just look like roads.
The minute I saw the raised curbs and meridian - in base game I knew at least that world would never have cars or bikes or anything else that required roadway programming. Sims 1 - 2- and 3 all had roads and road programming in base game even though Sims 1 and 2 had no ownable cars in base game - they did have usable vehicles though. Eventually Sims 2 did get ownable cars as well, sims 1 never did.
Sims 4 has none of that.
