Truck and Track Spring 2023 www.truckandtrack.com 8 BUSINESS NEWS Vehicle washing is often seen as an extra expense to a company. This is often offset based on the benefits of keeping a brand clean, driver welfare or regular maintenance. However, what if vehicle washing could improve your bottom line? The myth On a show called ‘Mythbusters’, they tested the fuel efficiency of a dirty car against a clean car. By using an average American sedan they tested the fuel efficiency of the vehicle when squeaky clean to the fuel efficiency when it was dirty. This was attempting to bust the myth that a dirty car is more efficient than a clean car. The myth suggests that the mud and dirt on the vehicle would create a ‘golf ball effect’ which would help it move through the air. This is based on the fact that dimples on a golf ball are designed to create turbulence around the ball’s surface which reduce the drag of the ball. A completely smooth golf ball is expected to travel half the distance of a golf ball with dimples. Therefore, a car with ‘dimples’ created by mud and dirt would therefore be more aerodynamic and hence more fuel efficient. In fact, the results on the show were the opposite. A golf ball is engineered to maximise lift with precisely located dimples, a car splattered in mud, is far from that! Why a clean vehicle increases fuel efficiency The efficiency of driving a clean vehicle comes from reduced air resistance, with debris and dirt attached to your car air does not move as freely over the surface of the car. Instead, it gets bogged down avoiding lumps of dirt and debris on the surface. With less air resistance, the air travels more freely over the vehicle and it is therefore more efficient. This can further be enhanced through waxing a vehicle, again creating a completely smooth surface for the air to travel over. The Mythbusters episode shows that a clean car will be 2 mpg more efficient, with an increase from 24 mpg to 26 mpg. With the cost of diesel being around 170 pence per litre then the saving is around 2.5p per mile. Based on the statistics that an average working van will travel 13,000 miles a year, this is a saving of £320 per year! But if you take that increase as a percentage, the van became nearly 8% more efficient with fuel! Vehicle washing can save you money?