Which is More Slippery – Leaves or Snow? Ford Engineers Reveal the Surprising Answer
COLOGNE, Germany, Nov. 21, 2018 – They may be a crucial ingredient in creating the stunning autumnal landscapes so beloved by photographers, but in certain situations – when they are wet and in multiple layers – leaves can present a significant danger to drivers.
Those in the know have long compared the effect to driving on snow. But could the humble leaf really be as slippery as the white stuff? A group of Ford engineers have come up with an answer – after conducting a unique experiment in order to find out.
Getting the data for the snow was the easy part. This was sourced from vehicle testing in snowy Scandinavian locations. But there was no research to show how slippery leaves were. To fix that, the team gathered bags of leaves and used them to cover the test track at the company’s proving ground in Belgium. They then called in the help of a friction-testing device that identifies how slippery surfaces are by rolling over them.
After testing they did indeed find that, in certain situations, the leaves were as slippery as snow.
“It was fun to conduct the experiment but there was a serious point,” said Eddy Kasteel, development engineer, Ford of Europe. “Most people know to slow down and drive more cautiously for snow. But far fewer of us give the same respect to roads covered in leaves – that can be just as slippery.”
Slipperiness is measured in units called µ. The more slippery the surface the lower the number. In testing, and at their most slippery, the leaves measured a µ level between 0.3 and 0.4. Typically, the same µ levels observed on snow surfaces
The same engineers helped to develop “Slippery Mode” for the all-new Ford Focus Active crossover that goes on sale next month. Designed to improve traction on surfaces including ice snow and wet leaves, the system makes rapid readjustments to stability systems, acceleration and braking to help prevent the car from skidding, swerving or deviating from its intended path.
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About Ford Motor Company
Ford Motor Company is a global company based in Dearborn, Michigan. The company designs, manufactures, markets and services a full line of Ford cars, trucks, SUVs, electrified vehicles and Lincoln luxury vehicles, provides financial services through Ford Motor Credit Company and is pursuing leadership positions in electrification, autonomous vehicles and mobility solutions. Ford employs approximately 200,000 people worldwide. For more information regarding Ford, its products and Ford Motor Credit Company, please visit www.corporate.ford.com.
Ford of Europe is responsible for producing, selling and servicing Ford brand vehicles in 50 individual markets and employs approximately 53,000 employees at its wholly owned facilities and approximately 68,000 people when joint ventures and unconsolidated businesses are included. In addition to Ford Motor Credit Company, Ford Europe operations include Ford Customer Service Division and 24 manufacturing facilities (16 wholly owned or consolidated joint venture facilities and eight unconsolidated joint venture facilities). The first Ford cars were shipped to Europe in 1903 – the same year Ford Motor Company was founded. European production started in 1911.