Fuel consumption is affected not only by your driving style but also by the use you make of auxiliary equipment while driving. Air conditioning increases fuel consumption and should be used sparingly. All extra use of electricity in the car influences fuel consumption. Among the auxiliary devices other than air conditioning which consume the most electricity are electric heating of seats and rear window defrosters.
Today's motorcars contain a good deal of high technology in the form of trip computers, GPS systems etc. One auxiliary device for driving economically which is used on EcoDriving training courses is called “the Econ” (Econen). This is a fuel gauge developed in Finland which is a very effective teaching aid, especially because it is so fast-acting. It measures impulses several times a second. You see this whenever you release the accelerator and the gauge "zeroes" itself immediately.
Engines naturally have to be adapted to suit the car’s size. However, there are many engines for the same model of car and so you have to think about what your needs are.
Exhaust emissions from new cars are only a small fraction of those from older models. Thus emissions of carbon monoxide, hydrocarbons and nitric oxides from models of the year 2000 are less than one tenth of the corresponding emissions from the1970 models.