Higher, larger pickup trucks did not come about as a result of safety requirements, they came about from fuel efficiency requirements (or needing to get around them).

So net result of indirect regulations to decrease fuel consumption is increased fuel consumption, and more dangerous vehicles for everyone to contend with who is not inside as large of a vehicle.

Simply making people pay more for fuel would have incentivized them to prioritize what kind of vehicle to buy, and make it possible for smaller pickups to still exist and/or a rental market for pickups to flourish.