Shifting Into Winter: Winter Tires, Driving, Energy Consumption, Tips & Expectations

Winter driving can be dangerous and also has higher energy consumption. However there’s a misconception that electric vehicles fair much worse than their internal combustion engine counterparts. Electric vehicles actually fair better on costs and efficient energy use. There are also measures you can take to help counter or reduce the impact on both range and consumption.

Tires are important!

Tires: The cooler it gets below 7° C, summer and all-season tires loose their grip. They suffer from a big increase of traction-loss to loosing most of their grip around -14° C. However, winter tires are made to gain grip as it gets cooler. With rain (and any form of frozen precipitation) this impact get even bigger.

Winter tires or chains are required on most routes in British Columbia from October 1 to March 31. For select highways, including mountain passes and rural routes in high snowfall areas, the date will be extended until April 30 to account for early-spring snowfall.

3.5 mm or more tread & a proper symbol

Mountain/Snowflake and/or
“M” and “S” lettering.

See the BC Government website tire and chains passenger vehicle requirements for more details.

Winter Driving: Avoiding problems

Drive for the conditions! Shifting your driving habits to tackle winter driving which puts our car and our skills to the test, is vital to avoid problems. There’s just too much unpredictability & variability to drive the same as we do during ideal conditions.

  • Drop your speed. The speed limit is for ideal conditions. Be ready for the inevitable unpredictability of snow and ice on the road. Its going to take you longer to stop as you’ll very likely have to slow down and maneuver slowly to maintain control.
  • Four second following rule minimum. At least double your stopping distance from others.
  • Always be looking and planning ahead for your stops, turns, and lane changes.
  • Adjust and smooth out your steering, braking & accelerations.
  • Black Ice is common in shaded areas, bridges, overpasses. Be extra vigilant when maneuvering in those area. Slow down slowly in advance if you know you’ll need to in those areas and coast through it otherwise.
  • Sharp curves & hills: Try to avoid accelerating and braking during turns, try and coast thought them. Slow down slowly before going down a hill.
  • Drive with headlights on in low light, fog, smoke, & snow to see and be seen.
  • Use extreme caution around road maintenance vehicles. Be ready with the wipers and whats ahead in case you have a few seconds of no visibility.
  • Practice how to handle skids in case you accidentally find yourself start or are out of control of your vehicle. If you start to skid, ease off the brake or accelerator, and look and steer smoothly in the direction you want to go. Be careful not to over-steer. When in a straight line try to shift into neutral or coast.

For more tips & resources on how to stay safe on the road this winter see the BC Government DriveBC website Shift Into Winter. DriveBC also provides current road conditions via an interactive voice response system. Call the Traveller Information System at 1-800-550-4997. For example to get the Highway 1 road conditions in the lower mainland say the following voice prompt at the main menu: Highways, Trans Canada Highway, Mainland, Conditions.

Drive BC Phone Tip: You can interrupt and speak the next option (or confirm by saying Yes) to speed up getting though the 4 levels of menu to get the conditions. Say Yes to confirm and say Main Menu to start over.

Higher Energy Consumption: The Cold Weather Factors

The U.S. Environmental Protection Agency (EPA) estimates that a drop in temperature from 24° C to 7° C can increase fuel consumption in urban commutes by 12 to 28 % for internal combustion engines.

Here’s some of the other factors and impacts

  • Cold, dry winter air is 11% denser (1.3 % impact) & its windier!
  • Rainy & winter road conditions (7 to 35 % impact)
  • Higher vehicle electric loads due to heating, defrosting, longer time with headlights on, heated seats, mirror, & more use of the wiper pump & motor.
  • ICE: Winter Fossil Fuels have less energy ( 1.5 to 3 % impact)
    BEV: Battery pack heating for optimal energy efficiency & cabin heating (5 % impact)

Model S and X Range curves appear similar

Model S 100D 22% less range when below freezing
Model X 100D 22% less range when below freezing

Are EV owners actually fuelling the myths and misconceptions about winter range?

As with all cars in the real world, electric vehicles don’t get anywhere near EPA mileage estimates during normal driving. However electric vehicle owners are well aware of our energy consumption and thus notice any impact. Thus its important to understand all the factors that cold weather drives up energy consumption.

The maximum range of Model S and X at temperatures below freezing is about 22% less than at temperatures above 20° C (68° F). For the Model 3, the ‘statistics’ are a little harder to come by. Reports of 25-30% loss at and below freezing to 40-50% at below -20° C. There are many factors that aren’t due to the battery rated range we see. Our expectations should have this loss in mind.

The chart below shows how the real world range is compared to the ‘rated’ range. This shouldn’t be excepted in cold weather conditions. Maybe we need an Igloo Mode to adjust the rated range for typical winter conditions?

Click on the image for a larger view.

As you prepare for winter, please read TESLA’s Winter Driving Tips to make the colder months a breeze and be aware of some mitigation strategies you can implement if you should desire or require them. The average regular trip and regular seasonal trips such as going to the mountains likely won’t require any effort in assuring your vehicles range ability.

Have a wonderful Happy Thanksgiving and please drive safe!