Diesel cars last longer and have fewer breakdowns owing to a simpler engine. With fuel consumption being 20-30% less, and costing less pump price these constitute real savings to a company with a fleet. There is concern over the particulate emissions, which are believed to be carcinogenic, but are not pumping out CO2 emissions

Petrol engine cars fitted with a three way catalytic converter reduce the amount of carbon monoxide, hydrocarbons and nitrous oxides but do not reduce CO2 emissions; they also use more fuel so increasing CO2 emissions.

New fuels such as bio-diesel and battery power and electric vehicles are being produced and should be considered for certain uses.

Electric vehicles appear to solve many of today's car-created problems. In the internal combustion engine, less than 50% of the energy is converted into useful energy to power the car. In an electric car this figure is closer to 90%. They are quiet, cheap to run, efficient and don't emit any toxic fumes.

Many people consider that the owners of cars and lorries should pay a 'green' tax, which represents the hidden costs that result from road use. These include the total expense of road building, accidents and pollution, which are paid for by the government, or not at all.