My car has a "cruising range" indicator telling me how many miles worth of petrol are left in the tank.
Coming along the M26 this evening, I chickened out and turned off at Wrotham and filled the tank, as according to the readout, I had 8 miles left before empty.
I bet there was loads left really!
(In fact I've just looked it up and apparently the fuel tank has a capacity of 45 litres, and it only took 35 litres to fill up - so I probably could have done another 100 miles!)