Sir, I totally understand why people want to park their cars outside their homes but with car ownership continuing to increase this is getting more and more difficult.

Demanding a guaranteed space immediately in front of one's house is unrealistic, but with a well-organised and properly enforced residents' parking permit scheme, in areas where it is needed, we should be able to park on the streets near our homes. Enforcing this, however, has a financial cost that I believe should be borne by those who benefit from it.

The increasing number of cars in Oxford also has an environmental cost. Not only are our roads congested but the carbon dioxide pumped out by cars and buses is polluting our air, damaging the environment and contributing to climate change. Tarmacing over gardens to create parking spaces and widening roads is only exacerbating the problem.

We should instead be supporting measures that reduce the number of cars and encourage other means of transport such as cycling, car sharing and using buses - preferably buses that run on biofuel that generate no harmful emissions.

In addition to the existing park-and-ride schemes, perhaps Oxfordshire County Council should consider introducing a congestion charging scheme so that visitors and commuters would also pay for the privilege of driving in the city.

Concessions could be offered for local residents, disabled drivers and those driving cars that have a low impact on the environment.

If the money raised from all of these charges on cars were spent on environmental or sound transport measures, as I believe the county council are obliged to do, we might have a less congested, less polluted and greener Oxford in years to come.

Joanne Bowlt, Summertown, Oxford