Explaining why wet leaves can be as slippery as ice on the road

SYRACUSE, N.Y, - The first accumulating snowfall of the season came to Syracuse and Central New York today, November 1st. It's that time of year where you have to be extra cautious while driving on these slippery roads. But it's not just the snow and ice you have to watch out for, wet leaves can be just as slick!

Let's use an example to show you just how much of a difference wet leaves can make when you have to come to a stop while driving. Looking at three conditions, a dry road, wet road, and a road with wet leaves.

If the cars are all driving at 40mph then have to come to a stop, it would take the car on the dry road about 80 feet to stop, the car on the wet road about 160 feet to stop, and the car on the road with wet leaves about 250 feet to stop. This means that it takes more than three times the distance to stop your car while driving on a road with wet leaves compared to a dry road.

But how do wet leaves become so slippery? Most plants take in water through their roots, so leaves are specifically designed NOT to allow water in. Instead, water sits on top of the leaf's waxy coating creating a film similar to that found on ice.

This slippery film is on both sides of the leaves, which means a road completely covered in wet leaves can have the same friction coefficient as ice. Slip resistance or friction coefficient describes how much traction two surfaces have. The lower the number, the less traction. The traction between wet tires and wet leaves or ice is fairly close to a friction coefficient of zero, which means there is not much traction.

It's not just the roads that pose a hazard, walking over wet leaves on sidewalks, driveways or parking lots can also be dangerous. The United States Department of Labor says 15% of all accidental deaths are from slips and falls, second to motor vehicle accidents. Both of which are impacted by wet leaves.

Syracuse is at peak fall foliage, but most areas outside of Central Onondaga County are past peak which means most of the leaves have fallen of the trees. That is why right now is the most important time of the year to drive cautiously because many roads have leaves on them. Plus, be careful walking around on the sidewalks! Stay safe this fall!