Which would give you better gas mileage?
If you're asking about highway vs city streets, highway wins simply because you keep a constant speed rather than stop n' go driving. Continuous stopping and accelerating takes its toll on fuel economy.
But if you're asking about a direct comparison, say one car doing 60 MPH vs another doing 80 MPH, both on the highway, the vehicle travelling at 60 has less aerodynamic drag to overcome and will get better fuel mileage.
Gas mileage has nothing to do with distance over time.
Highway miles would give MOST cars better fuel mileage, however hybrids tend to excel at city(slower) speeds and do better in the miles per gallon category off highway.
The best fuel economy is always achieved when driving at a consistent speed.
slower speed taking more time. Your engine gets the best mileage at lower RPM.
stop start traffic will use more fuel than driving on the freeway at the speed limit with the cruise control on