Once again, we're getting into mid-to-late fall, when temperatures through most of the Continental U.S. start to drop significantly (the Coastal-California area, with its year-around mild weather, may be one of the few exceptions). Two things, in general, this time of year, for vehicle owners/drivers, need more than the usual amount of attention and caution.

First, it is deer-mating season, and, with the inevitable quest for romance, large males (bucks) are typically chasing after smaller females (does). Often oblivious to traffic and danger, they will sometimes charge right across roads, with little or no warning. Obviously, a collision with an animal that size, besides the injury or death it causes the poor creature, certainly does one's vehicle no good. Indeed, a friend of mine, some years ago, totaled his Mazda MPV minivan hitting a deer...it was only a little more than a year old, so that shows you what kind of damage can be done. Worse, the deer, before hitting the windshield, bounced off the front fender, in a spot that did not trigger the air-bag sensor, and his wife, riding shotgun, ended up needing a number of stitches from the impact (she otherwise survived OK). In the D.C. area, this fall, I haven't seen as many deer running across the roads as I usually do during mating season...but it still bears caution and keeping one's eyes open, even with some of the new automatic-braking systems that automatically scan for obstacles and stop the car for you.

Second, the drop in air-temperatures can and does affect the pressure in your tires....(roughly) 1 PSI for every 10 degrees in air temperature. The recommended cold PSI for your tires (which means after the tires have been sitting overnight or out of the sun, in the shade, for at least 3 hours) can be found in the Owners' Manual, on a sticker down low on the drivers' door-jamb, or, in some cases, on a sticker inside the glove box. Do NOT go by the PSI figure moulded into the tire sidewall, in the black rubber....that is the maximum PSI allowed for safety reasons. As the temperature drops (particularly on cold mornings), you may have to add some air. I keep a portable air-compressor in my trunk, for that very reason (they typically cost $30-50), that plugs into the car's power-outlet, for that very reason....and, of course, if needed, to be a Good Samaritan to others, should they be stuck with a flat. Newer vehicles, of course, have the built-in tire-sensors that monitor the PSI for you. Some of them (if the bean-counters at the factory don't win) actually display all four PSIs in the tires.....others (if the bean-counters win) cheap out with less-sophisticated sensors that simply compare wheel-rotation specs and flash a warning light if one or more them is slow. A tire wth low pressure, of course, will have a smaller outside diameter, and roll faster at the same road-speed. If the light flashes, you sometimes have to go find which tire it is by actual inspection. Even the more sophisticated individual-tire sensors aren't always foolproof...they sometimes take a minute or two, on a cold morning, to stabilize the reading after the car starts rolling, so you can't necessarily rely on their initial reading.

Yes, it can be a nuisance (I'll be the first to admit it), when the outside temperatures swing up and down wildly, such as in late fall and early spring, to have to continually add more and more air to the tires as the temps drop...then sometimes have the tires with too much pressure if the temperature suddenly goes way up, or if you generate a lot of heat with them by driving fast with the car heavily loaded. But, until the engineers can come up with a mass-produced vehicle-tire that can operate normally, on paved roads, without air, that's basically what we are stuck with. Yes, run-flat tires come on some vehicles, but, if the air leaks out, they are generally only good for about 50 miles or so, at 50 MPH or less...hopefully, to get you to the nearest repair or tire-shop. They can be expensive to replace, short-wearing, and their stiff sidewalls (to support the car's weight, of course, without air), can give a relatively uncomfortable ride.

 

Lower winter air temperature affects not only tire pressures but affects the softness of the rubber in the tire also. That is why it is suggested that when the air temperature drops to consistently below 7deg Celsius (~45deg Fahrenheit), that it is time to switch to winter tires.

As the temperature drops, the rubber in tires hardens and dry pavement grip lessens. At 7deg Celsius, all season and winter tires have about the same grip on dry pavement. Below 7deg, the all season rubber becomes too hard to provide good grip but the winter tire rubber still remains relatively soft, providing greater grip than the all season tire.

 

Good point. I noticed that, with all-seasons, cold air-temperatures, even wth lower PSIs in the tires, can give a stiffer ride over bumps, not only from the tire-rubber being harder, but also from the fluid in the shocks being thicker and giving stiffer dampening. In my area, with all-seasons, take the same tire in January and July, on the same road, under the same conditions, and you will often notice two completely different rides....at least with the cars I've owned in the past. The new Lacrosse, though, doesn't seem to be losing as much ride-comfort, as the temperatures drop, as my last several cars did....perhaps other factors are coming into play.

 

I've noticed exactly that with the colder air temperatures and the skinny rubber band tires/18" wheels I have on my SC. Car rides rough around town on bad roads but the ride settles down a lot on the interstate, even on parts that are beat up.

As for deer, this was years ago when I had my Camaro convertible, I thought I was going to die. Late at night, top down, doing 55-60mph on a 4 lane road, nobody else around. Deer darts out from the left, I slam on the brakes, keep it straight and true, no way I'm going to stop in time. He sees me, sprints across the road, I say thank god, I'm going to miss him. He then realizes the right side is like a 20-30 foot drop straight down, decides to turn around and double back across the road at the last second, ends up grazing the rear of my car, antler takes off the antenna, there is just a little bit of fur on the paint where you can tell he grazed it, no dent somehow. I thought for sure he was coming over the passenger side door and into the car with me.

 

My TPMS sensors usually start acting up in cold weather. Had to take it to the dealer to get it reset last year. Dealer took care of it at no charge and said they had 85 instances of this problem in 2 days.

The deer are annoying, but so far they seem to stay on the shoulder here in North Carolina, knock on wood.

 

Don't forget: Wipers on/headlights on. Although this applies all year long, with early sunset starting in November, it's even more critical to be visible in bad weather.

 

Most of the modern cars I've owned have an AUTO switch which, when set, automatically turns on the full-headlights when it is dark enough (either at night or in a tunnel) and keeps the lower-intensity DRLs (Daytime Running Lights) on during the day or in brighter conditions. The DRLs might not meet the actual spirit of the lights-with-wipers law, but they seem to meet the letter of the law....particularly with the front LED display on my LaCrosse. In a number of years of driving with DRLs and the wipers, I've never had either a local cop or State Trooper stop me or say anything to me about it....neither has anyone else I've known.

 

Auto-headlights should be mandatory, in my opinion.

In my experience, they're a bit unreliable when it comes to rain. Even in my IS, they sometimes come on when it's raining, sometimes not, basically depending on how dark the clouds are... So, one still has to be aware.

 

Many auto headlights don't come on in rain/fog/snow. Some cars are starting to have auto headlights come on when the wipers swipe for about a minute or so. My BMW has this feature, as does my mom's CRV.

I agree on the DRLs, but there are bad weather conditions, such as fog, where you should want to have your tail lights on too, which aren't on with the DRLs.