If your regular journey is too far to cycle, it may be worth thinking about an electric bike. This would give you a much bigger potential range, and be more efficient than a car. There's a useful guide to electric bikes on the A to B Magazine website.
Car clubs offer an alternative to owning a car, and reduce car use while still providing the convenience of private transport. They offer both carbon and financial savings, as people only make use of the vehicle when they really need to. Research has shown that a car club car replaces between four and five privately owned vehicles, and travel patterns change considerably. For example, in Berlin, car club members reduced the miles they drove by 53%, walked or cycled 28% more and used public transport 35% more than private car owners. There is more about car clubs and car sharing on the CarPlus website.
When looking at buying a petrol or diesel car, note that the fuel economy of similar sized cars using the same type of fuel can vary a lot. The Environmental Transport Association Car Buyer’s Guide gives an assessment of all cars on the market. Vehicle excise duty is now based on a car's carbon emissions, so less polluting cars pay less road tax. The VCA Car Fuel Data website includes a comprehensive list of emissions data for recent vehicles.
In our Zero Carbon Britain report we see electricity as the key fuel of the future. Electric vehicles are already less polluting, and this will improve as the UK electricity grid makes more use of renewable energy. Developments in battery technology will also improve performance and reduce costs. Several manufacturers are launching new electric cars, and the Energy Saving Trust website has more on current grants and where to find charging points.