Modern small cars with small engines can be quite fuel efficient in highway driving, though, and there 40 mpg isn't quite the very top. A month ago or so I did a trip in a 2016 Seat Toledo (petrol, non-hybrid), and the drive computer reported the consumption as 3.9 L/100 km after 150 km of driving at speeds from 60 to 100 km/h, averaging IIRC 78 km/h.
A 80 km strip at 120 km/h increased the average to 4.2 L/100 km.
Modern small cars with small engines can be quite fuel efficient in highway driving, though, and there 40 mpg isn't quite the very top. A month ago or so I did a trip in a 2016 Seat Toledo (petrol, non-hybrid), and the drive computer reported the consumption as 3.9 L/100 km after 150 km of driving at speeds from 60 to 100 km/h, averaging IIRC 78 km/h.
A 80 km strip at 120 km/h increased the average to 4.2 L/100 km.