Bad drivers spend more than two thirds more on petrol than the best drivers - which is costing them almost £50 a month.
See also: Revealed: the UK's worst roads, costing a fortune in repairs
See also: The most expensive place in the world to park
Direct Line Drive Plus looked at driving styles, including how hard people accelerated and braked, and how smoothly they cornered. The smoother their style, the better their score.
They discovered that smooth driving can almost halve the number of petrol station stops drivers need, and save motorists over £560 per year. Those with the worst driving habits drive an average of 413 miles between petrol station fill ups, compared to 693 miles for those with the smoothest styles.
It's not just how you drive. How fast you drive has an enormous impact on petrol consumption too, and regularly going too fast on the motorway can easily cost you 25% more in fuel.
It's also worth seriously considering how you use the car. If you have got into the habit of jumping in to pop to the shops, rather than taking a five minute walk, it may be costing you more than you think. Not only will starting the engine up a couple of times for a short trip use proportionally more petrol, but the most wear on an engine is done when it is cold, so you are effectively getting maximum wear and tear on the engine for the minimum possible benefit.
Chucking extra junk in the boot can also prove costly. The heavier the car, the more petrol it needs to get it down the road, so your inability to clear the clutter can be costing you a fortune in additional petrol.
If you can clean up your habits, stop the short journeys, slow down, drive more smoothly, pump up the tyres and clear the junk, therefore, you could save £750 a year.
Surely that's the kind of saving that's worth a bit of effort.