Wouldn't it be lovely if there were no cars on our streets, and we all travelled on foot, by bike, bus or train? Well that's what Sustrans are hoping for from 1st to 7th July with their Change Your World campaign. They are asking the great British public to swap at least one car journey for an alternative method of transport. They claim that if everyone gives up their motor for a day during that week, traffic will be cut by 10%. Cars make up 13% of the UKs total CO2 emissions, but if you swap to bus or train you'll contribute six to eight times less, and taking a bike will not produce any emissions at all. It's not that difficult for most of us, especially as most car journeys only average a couple of miles. If you feel inspired then you can sign up on the Sustrans website. They will even send you a reminder nearer the time to ensure you don't accidentally forget about your pledge! So, get out the car and get on yer bike!