Our published fuel consumption guide of 16 - 18 miles per gallon (MPG) is there to allow people to budget and plan for your trip. As stated it is guide only and is the average for an entire trip that includes both city and highway fuel consumption. We have found this range to be a good approximation.
What you can control:
Speed - Cruising over 60mph will dramatically increase fuel consumption, whilst cruising at 55mph will give you excellent fuel economy
What you can't control:
Wind - If driving into a headwind it greatly impacts on the fuel usage.
Terrain - Driving over hills will increase fuel consumption as the engine is working much harder.
We highly recommend that you drive conservatively. This will give you the best fuel consumption. You are on holiday, take it easy. Please also be aware of vehicles behind you and pull over where safe to let faster vehicles pass you.