Fuel consumption experiment

I finally have a good idea that will probably work. I am planning to investigate the relationship between the average speed of a car and the fuel consumption. Data will be collected from the trip computer records on our car.

Independent variable: average trip speed (km/h)
Dependent variable: fuel consumption per 100km

The car makes a number of journeys on many different routes, which will allow collection of large amounts of data.

Aim: to investigate whether it would be more environmentally friendly to build a motorway through the city, or to maintain the current system of minor roads.

Hypothesis: As the average speed increases, the fuel consumption per 100km will decrease, then begin to increase as air resistance becomes a factor.

The method will involve investigating the fuel consumption of the car over journeys generally (eg. travelling to school, work, and sport), with average speeds, and comparing this to the fuel consumption when driving on routes where more than 50% of the journey's distance takes place on a motorway. This will be quite practical as we frequently drive relatively long distances within the city both along regular roads and also along motorways.

The result of the experiment will be to see whether including more motorways in metropolitan road infrastructure would decrease fuel consumption among family vehicles.

Some variables that need to be controlled: the amount of weight carried by the car will vary sometimes, but this should not affect the experiment as it is averaged out. The only time that this may affect results is if the amount of weight in the car was consistently different for trips on motorways and regular roads.