As the credit crunch bites, UK drivers have been advised how they can cut down their motoring costs.James Harrison, chief executive of price comparison website insurance.co.uk, recommends deploying measures such as avoiding high speeds on the motorway, as the average car consumes 38 per cent more fuel at 70 mph than it does at 50 mph."Don't carry around in your car any items you don't need regularly. On average every 50kg extra will increase your petrol consumption by two per cent," he added. Mr Harrison went on to say avoiding accidents and speeding tickets can also cut down running costs because claims-free motorists can be rewarded with discounts of up to 70 per cent, while getting a ticket adds an average of 13 per cent to insurance premiums.Last week, price comparison website uSwitch.com claimed government plans to increase the car tax bills of nine million motorists will cost British drivers an extra £25 a year on average.