WASHINGTON, D. C. (Tuesday, October 10, 2017) ––For nature lovers everywhere, the fall foliage is a thing of beauty. It is the unrivaled season when it is said the “trees and other flora turn into brilliant shades of yellows, oranges, purples and reds.” Despite autumn’s multihued majesty, there is a downside to the blanket of fall that covers the landscape, the countryside, and city streets. As pretty as they are, for motorists the fallen leaves of autumn can be slippery when wet, causing road hazards; and highly combustible when dry, posing fire risks for parked vehicles with faulty mufflers and exhaust systems, warns AAA Mid-Atlantic.

Don’t leave leaves alone this time of year because they can prove hazardous to your health, restricting the cabin air supply once leaves accumulated on and under the hood clog  the air vents, the  air conditioning unit, and the vehicle’s ventilation system. The leaves deposited by deciduous trees can also obstruct air intakes on your vehicle, such as the “fresh air intake (‘the air from outside the vehicle’) and the recirculated air intake (the ‘air from inside the vehicle’).” Plus, all that “sap, tannic acid, and pollen” found in the fallen foliage can prove abrasive to the pristine clear coat of automobiles. Once wet, it can leave behind “fossil-like” leaf stains that are hard to remove. Left untreated, it can cause rust to crop up on the vehicle’s finished paint surface.

During the fall, residents across the Washington metro area rake leaves into piles at the curb. To speed up residential leaf collection and to avoid a fire hazard, they are advised to move parked cars off leaf piles.  During autumn, hot exhaust system components, including a faulty catalytic convertor, can spark a fire when they come in contact with fallen, dry leaves, warn AAA Mid-Atlantic and the National Fire Protection Association (NFPA). So can blown tires, overheating engines, defective electrical wiring, broken fuel lines and other mechanical or design problems. Your vehicle’s exhaust system consists of one or more catalytic converters, one or more mufflers, and one of more oxygen (O2) sensors, AAA Car Care Centers explain.

“Weather, of course, plays a significant role in the annual metamorphosis of leaves,” said John B. Townsend II, AAA Mid-Atlantic’s Manager of Public and Government Affairs.  “The fallen leaves can cover area roadways and sidewalks, compromising safety for drivers, children, pedestrians and cyclists, especially on rainy days when roads, crosswalks, and the leaves are wet and slippery.  Consider this, ‘fallen leaves are slippery because they ‘contain a large amount of water.’ Wet leaves can be as slippery as a sheet of ice.”

A single big oak tree in your yard will yield “1.25 million to 2 million” fallen leaves. Each fall, fire departments around the country warn motorists about “the potential dangers and fire hazards that can occur by simply parking their motor vehicle in certain areas.”  Motorists should avoid parking on fallen, dry leaves or in tall grass. Vehicle fires comprise about 20 percent of all reported fires in the United States of America, according to National Fire Protection Association (NFPA).  “U.S. fire departments responded to an estimated average of 229,500 vehicle fires per year in 2007-2011,” the NFPA reports.  “These fires caused an average of 328 civilian fire deaths, 1,426 civilian fire injures and $1.4 billion dollars in direct property damage per year.”     

There have been many examples of car fires that were caused by the extremely hot catalytic converters of the cars’ exhaust system igniting the dry leaves,” warns the Montgomery County Department of Transportation. “As you behold the beauty of the leaves, think about the hazards too,” said Jim Malervy, Automotive Solutions, AAA Club Alliance. “Dried leaves from deciduous trees could be ignited by a car’s heat. “If possible, avoid driving or parking over leaves. Leaves blown across roadways by heavy wind gusts can make it more difficult for drivers to see the road surface, potholes and other road debris and hazards. So slow down and take safety precautions.”

When deciduous trees give up their dead, a pile of dry leaves  can be ignited by the car’s catalytic converter. Here is how. A catalytic converter, which reduces the level of harmful pollutants in the exhaust, normally operates within a “temperature range of about 1,200 to 1,600 degrees Fahrenheit,” according to How Things Work.”  Once “clogged or overworked,” however, the temperature inside the catalytic converter can soar to “up to over 2,000 degrees Fahrenheit,” research shows. Your vehicle’s exhaust system has come a long way from the old days of exhaust pipes and mufflers, explains Malervy. Think of it this way: “If there is a partial ignition system failure, such as one or more misfiring spark plug or defective ignition wires, the temperatures of the catalytic converter surfaces and the exhaust system downstream from the converter may reach 1200 to 1400 F,” warns the Texas Commission on Environmental Quality.

“Drivers should slow down when roads are covered with wet leaves and take turns and off-ramps more carefully,” warns James Spires, Regional Manager, AAA Car Care Centers. “Fallen leaves can cover potholes and act as camouflage for curbs, causing damage to tires and suspension systems when drivers drive over or smash into them. A blown tire or broken suspension part can cause you to lose control of your vehicle.  For safety’s safe, before starting your vehicle, remove any leaves from your windshield to prevent them from getting stuck under wiper blades.”

“All the leaves are brown, and the sky is grey.” The fall leaf collection and leaf vacuuming regimen in the Washington metro area begins as early as October in some area jurisdictions, and it normally starts during the first weeks of November and runs through January in the nation’s capital.  During the season, leaf crews collect leaves raked to the front curb with a vacuum truck in some jurisdictions such as Alexandria. Curiously, “deciduous trees” derive their name from the Latin word picture ‘to fall off,’ and it refers to trees “whose leaves fall off.” The problem is that leaves carry sap and pollen—both of which have acidic properties, just like bird droppings. The acids in sap and pollen are corrosive to your car’s paint.

WHAT CAN YOU DO ABOUT IT?

• Don’t park on a pile of leaves. As the leaves undergo a spectacular transformation in the fall, motorists must remember “parking on a pile of dry leaves can be a fire hazard.” 

• Don’t drive over a pile of leaves.  Kids and some dogs love to play in piles of leaves. Wet leaves on the roadway cause hazards to vehicles attempting to stop, start or change direction.”

• Slow down if there are large patches of leaves on the road. This reduces the chances of being in a crash.

• Don’t park under trees. Because trees make leaves, and leaves fall off, and leaves do damage to cars.

• Get a cover for your car. This will also protect it from bird droppings, hail, and more. The downside is that if you don’t have a cool or expensive car, the cover will make your neighbors think you’re full of yourself.

• Remove leaves from your car right away. Use your hands to do this. You’ll want to use a broom if there are a lot of leaves, but you’re likely to scratch your car’s paint with the broom, which defeats the purpose.

• Wash away the stains immediately. Think fall cleaning, and wash the vehicle regularly. Use a soft cloth and a liquid car wash solution to wash away sap/pollen residue. Spray away leaves in the undercarriage.

• Wax your vehicle when the final leaf falls. Once fall ends, get you waxed or have it detailed.

To learn more tips or about other solutions AAA provides motorists and their vehicles, please visit AAA.com/Automotive.

Follow us on Twitter: @AAADCNews

Like us on Facebook: AAA Mid-Atlantic News

Washington, D.C. Mailing Address:
1405 G Street NW
Washington, DC 20005

AAA provides automotive, travel and insurance services to 58 million members nationwide and nearly 78,000 members in the District of Columbia.  AAA advocates for the safety and mobility of its members and has been committed to outstanding road service for more than 100 years.  The not-for-profit, fully tax-paying member organization works on behalf of motorists, who can now map a route, find local gas prices, discover discounts, book a hotel and track their roadside assistance service with the AAA Mobile app for iPhone, iPad and Android. For more information, visit  https://aaa.com