The amount of fuel can go negative to a point, but the gauge won't read below 0 liters. When refueling, a vehicle will still have to consume fuel to get above 0 liters.

Vehicles can always be sent to depots, even if out of fuel, so you can recover vehicles and unblock your roads. Realistic? Maybe not, but the game does need to compromise somewhere to be playable.

With used vehicles transport and maintence stations, there could be rule to dispatch open haul truck for stuck vehicles. Just for masochists like OP. :P

Originally posted by Stele:

With used vehicles transport and maintence stations, there could be rule to dispatch open haul truck for stuck vehicles. Just for masochists like OP. :P

Interesting. But, the BZ-252 while technically stuck without fuel, game just teleports it.
- I like your suggestion about adding an option for maintenance stations in realistic mode.

If it were up to me, I think my preference would be to implement a task for the Technical Office (free) or Technical Services building. In the event of a road vehicle running out of fuel, the TO/TS building would dispatch an oil tank / fuel carrying capable vehicle to bring a tank of gas to the beleaguered machine.

The main problem I can see with this is that, if the empty vehicle is causing a jam, the TO/TS vehicle would need to be able to "bypass" the stopped traffic, or else you'd run into a catch-22 where you can't fill the vehicle because of the jam, and you can't fix the jam because you can't get to the vehicle to fix it. I have no idea how much problems that would cause the devs. Perhaps if it was part of a larger update that implemented the ability for road vehicles to pass stopped traffic.

Out of fuel vehicle can park to the side and have collision disabled. Tow truck can bring it fuel or tow it to the station. The tow truck could still cause traffic while it's assisting the stranded vehicle for a minor penalty.

Could add traffic accident disasters in that case, if we get tow trucks...

But there are probably better things to work on, like better utilization of lanes.