Even the slightest bit of rain can be dangerous.
Before motorists have to deal with snow in the winter, they’ll encounter more wet conditions in the fall. Rain can cause surfaces to become slick, especially near intersections, particularly after it has been dry. Rainwater can mix with oil and other vehicle fluids that have leaked into the pavement.
Driving.ca notes that even with good tires, braking on wet pavement is about half as effective as dry. If, for example, a child darts out between cars in a residential area, or a car or pedestrian cuts across your path, a vehicle travelling at 48 km/h will require 37 metres to stop when it’s wet — about the length of three school buses. Reducing that 48 km/h to 32 km/h cuts the stopping distance by more than half, to just 18 metres. Even a little slower is safer.
Driving in a downpour has obvious risks, but a 2019 study published in the journal Bulletin of the American Meteorological Society highlights how even light precipitation can increase the dangers. The results found during precipitation there is an increase of about 34 per cent of the overall risk of a fatal car crash occurring. The risk was worse during winter and the morning rush hour.
Researchers analyzed past radar data to identify what the weather was at the recorded time and location of 193,840 reported fatal crashes from across the U.S. for 2006 through 2011. They found the risk increased by about 26 per cent and 146 per cent for their classifications of light and heavy precipitation, respectively.
Remember, speed limits are set for ideal conditions, not for when it’s raining. Driving safely means slowing down.
Michelin Canada offers drivers some tips on how to deal with rain when behind the wheel.
“Wet weather doesn’t receive the same attention as winter weather but it should,” the tire company’s website says. “Wet roads present similar dangers – less grip and longer stopper distance, for example.”
What is hydroplaning?
Heavy rain can create puddles or standing water on the road, increasing the risk of hydroplaning. When this occurs the tires slip and do not respond to steering, braking or accelerating. The vehicle can even skid or spin. It occurs when the water between your tires cannot be removed quickly enough. This layer of water builds up in front of the tire and this is when it loses contact with the road.
In order to regain control, don’t hit the brakes suddenly and ease off the gas gently until you slow down and gain traction. (If you keep your foot on the gas, your vehicle could move in the wrong direction when your wheels regain traction.)
How to avoid it:
Rain also reduces visibility. The Official Ministry of Transportation Driver's Handbook recommends motorists:
Sometimes an accident happens, even when you've done everything you can to prevent it. In the event of a mishap, call police and your insurance broker for immediate assistance.
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