driving in the rain
November 30, 2019 3:15 AM   Subscribe

When you're on the highway and it rains so hard you can't even see the car right ahead of you what do you do?

Sometimes there are obvious places to pull over, like gas stations. BUt sometimes there are just narrow shoulders.
It seems totally dangerous to sit on a narrow shoulder when no one can see you or the where shoulder even begins from the road. What if someone else decides to pull over there? Or if they just can't see where the margin is - isn't it likely they will plough into the shoulder? But driving when you literally can see nothing is insane.
Where I live in the midwest this happens not infrequently. And it can last for long, long minutes with zero visibility. The shoulders are tiny.
I hate it, I have googled it a lot, I am still struggling with best practice.
posted by nantucket to Travel & Transportation (23 answers total) 12 users marked this as a favorite
 
The most dangerous place I had this happen was on the motorway in very thick fog in the dead of night. I mean, I couldn’t see in front of me at all, it was a wall of white. There was no shoulder to pull off to and no turnoff. In short, there was no way of getting out of it except going through it.

What I did was slow down drastically. I didn’t want to stop, because someone would likely hit me but I slowed down enough so if I hit someone else hopefully it wouldn’t be life threatening. Then I crawled through it for a few miles. When the fog finally cleared, I had crossed over four lanes without knowing it. Being so late at night I think there was only a couple of other cars out and they were nowhere near me. I got very, very lucky. I still don’t know if there was a better way of approaching it but I’d be happy to learn of one. It was terrifying.
posted by Jubey at 3:27 AM on November 30, 2019 [14 favorites]


In North Carolina I’ve found that it’s pretty common to just slow way down and put on your hazards while driving
posted by raccoon409 at 3:45 AM on November 30, 2019 [47 favorites]


Headlights and hazard lights on, slow waaaaaay down and pull off in a more visible area if you can, eg under a bridge. I also find, for reasons I’m at a loss to explain, that amber sunglasses let me see better in heavy fog or rain than I can without them. They seem to increase contrast somehow.

Of course I’m assuming you actually can see some short distance in front of you, if only very little, and you can pick out a few shadows, bright lights, etc. If it were truly equivalent to being blindfolded then feeling your way to the edge of the pavement is the most you should do before stopping. Nobody drives when truly blind.
posted by jon1270 at 3:46 AM on November 30, 2019 [7 favorites]


When this happened to me southbound out of Sydney on the freeway, I swallowed the huge lump of fear in my chest and pulled over, then sat on the shoulder trying to be as visible as possible, with hazard lamps flashing and my foot on the brake and the transmission in reverse, remaining utterly shit-scared as insane people kept on howling past at what felt to me like the full 100 km/h speed limit.

Stayed put until the rain cleared enough to see that in fact most of the driving population was apparently not insane and had done much the same thing as me.

It was fucking terrifying, pulling over, because at every instant I felt like I was walking this tightrope between inviting a rear-ender and plowing into somebody else who had already stopped. But there was this moment of clarity as I realized that every second of delay in pulling over was increasing the likelihood that I would plough into somebody else, and that doing anything else is - as you correctly point out - insane.

Best practice, it seems to me, would involve maintaining weather awareness and pulling over under the next overpass whenever it looks like it's threatening to get thick enough to leave me facing this dilemma again. Which is obviously not always going to be practical; sudden overwhelming rain dumps are a thing. So next best is pulling over, as far off the traffic lane as you can manage, then bracing for rear-end impact by jamming the head against the headrest and hoping for the best. It's just a shitty situation.

With any luck, if you do get rear-ended it will be by somebody travelling relatively slowly and also looking to achieve a safe pullover.
posted by flabdablet at 3:53 AM on November 30, 2019 [5 favorites]


I get the head against headrest thing, but wouldn't it be safer to put the car in neutral with your foot on the brake if you think your going to get rear-ended? Seems like it would reduce the severity of the collision, and prevent damage to your transmission.
posted by postel's law at 4:55 AM on November 30, 2019 [1 favorite]


What's going to damage your body in any car collision is acceleration. If you're going to get rear-ended, then the more of the crash energy you can persuade the parts of your car behind you to absorb as crumpling and the less to translate to acceleration of your body, the less damage you'll take.

If your car is going to be hit from behind so hard that the crumple zone would extend as far forward as your good self, then trying to avoid that by allowing it to be punted down the road instead will not save you from serious injury.
posted by flabdablet at 5:07 AM on November 30, 2019 [2 favorites]


Slow down. Turn on the blinkers/emergency flashers. Definitely pull over under an overpass if possible.

but wouldn't it be safer to put the car in neutral with your foot on the brake if you think your going to get rear-ended?

Putting it in neutral, maybe. But, if you have the brake pedal pressed, that would actually make the impact worse, or at least more destructive to the car, as it would make your car more immovable. Leaving the brakes off would allow your car to be pushed forward with the force of the impact, which would help dissipate some of the force.
posted by Thorzdad at 5:07 AM on November 30, 2019 [2 favorites]


at least more destructive to the car

If I'm put in the unfortunate position of facing a direct trade-off between damage to my car and damage to my body, I'm picking the damage to the car. Every. Single. Time.

And I live in a country that has a functioning public health system.
posted by flabdablet at 5:14 AM on November 30, 2019 [6 favorites]


That said, allowing your car to be punted down the road is potentially less damaging to the driver who rear-ends you.
posted by flabdablet at 5:16 AM on November 30, 2019 [1 favorite]


If I'm put in the unfortunate position of facing a direct trade-off between damage to my car and damage to my body, I'm picking the damage to the car.

I guess what I'm saying is, you are probably more likely to be injured if you have the brakes set in the case of a rear-end collision.

And, you can use the brake immediately after getting rear-ended, to stop forward motion. It'll probably be an automatic move on your part, anyway.
posted by Thorzdad at 6:06 AM on November 30, 2019


what I'm saying is, you are probably more likely to be injured if you have the brakes set in the case of a rear-end collision

and what I'm saying is, despite the obvious intuitive appeal of this position, the physics of crumple zones and passenger safety cells and seat belts and airbags and squishy human parts more than likely make it wrong.

What you want, if you're willing to risk remaining inside your pulled-over vehicle for the sake of not being further removed from the potential crash site at the cost of being wet and cold outside it, is the best approximation you can get to having the bottom of the car epoxied onto the road surface. You want the safety cell that contains you to accelerate as little as possible, and the crumple zones that surround it to deform as much as possible. So apply as much braking force as you have available to you: parking brakes on, main brakes locked, engine stopped and transmission in low gear.

Any crash with enough energy to exceed the combined absorption capacity of the crumple zones in both the colliding vehicles will dissipate enough energy that having any significant fraction of it converted to blunt force trauma to your delicate squishy parts will end badly for you. But force is proportional to acceleration, and there's no truly sound reason to risk acceleration injury in the likely event that your crash has less energy than that.
posted by flabdablet at 6:25 AM on November 30, 2019 [1 favorite]


I was slightly puzzled by the advice to “pull over under an overpass.” The important issue is not getting hit, not not getting wet. It would actually be better to pull off just past an overpass, since the clear visibility under there would give someone the longest-range view of you.

I am on team “proceed slowly,” because getting hit at 60MPH when you’re going 20 is (counts on fingers) less than half as bad as getting hit at 60 when you’re stationary.
posted by Gilgamesh's Chauffeur at 6:42 AM on November 30, 2019 [1 favorite]


Being visible in horrible conditions is critical. Car in reverse means more rear lights are on. Not sure how I feel about this strategy, but it makes some sense. Team Hazard lights and slow way down. There are always reports of pileups caused by fog or blinding rain/ water on roads.
posted by theora55 at 6:43 AM on November 30, 2019 [1 favorite]


Like everyone says; go slow and try to pull over. If you can't see you shouldn't be driving.

But on a fancy car there's a trick that might help in poor-but-not-awful visible conditions. In particular, if you have cruise control with the ability to pace the car in front of you, turn it on and see how it does. If it uses radar like most do, it can "see" through the rain a lot better than you can. In no way is this a substitute for you driving, but sometimes it feels like my cruise control can do a better job maintaining a safe distance to the car in front of me than I can. (While you're at it, increase the following distance if it's configurable.)
posted by Nelson at 7:01 AM on November 30, 2019 [2 favorites]


It is illegal in many states to drive with your hazard lights on.
posted by saladin at 7:11 AM on November 30, 2019 [3 favorites]


I look at the NOAA Weather website and click on the forecast discussion link. A meteorologist can often give you a really useful hourly prediction of where the precipitation will be, including radar of the local area. Then I look at the traffic map for the Los Angeles/Orange County driving area which gives me a detailed description of speed of travel on the road and hazards.

If it looks like it's going to happen, I avoid putting myself in that situation. The internet is really your friend. Well, and especially scientists. Lots of people just ignore all the warnings.

Also good daylight visibility.
posted by effluvia at 7:59 AM on November 30, 2019 [2 favorites]


Reverse, brakes, etc while stopped is a minuscule factor in damage to you and your vehicle - once the collision starts, the friction between your tires and the road switches from static friction to dynamic friction, which is much, much lower. That is, if your tires are even still on the road.

I believe what flabdablet was getting at with "my foot on the brake and the transmission in reverse" is related to the previous clause in the sentence - trying to be as visible as possible.
posted by notsnot at 8:58 AM on November 30, 2019 [1 favorite]


First thing I do is get off the road, way, way off the road because other cars will follow your tail lights if you are near the road. So if an interstate highway, don't just pull off to the right of the fog line. Drive all the way into the barrow pit if you can. Use your turn signal to indicate you are leaving the road.

If the shoulder is too narrow to pull off, then I put on my flashing hazard lights and slow way, way down if I can't see any distance ahead. Do not stop if you can't get your car well to the right of the fog line.

It is illegal in many states to drive with your hazard lights on.
Screw that. This is a life or death situation. If you slow way down because you can't see ahead and can't pull off the road because the shoulder is too narrow and don't put on your flashers, some nut is going to plow into the back of you at 60 MPH. The flashers give at least a little warning to the person behind that someone is driving slow ahead of them. Even in dense fog, people can usually see a flashing red glow ahead that should give them warning of a slow or stopped vehicle.

While driving slow with flashers on, I scan for anywhere that there is a pull out. A wide spot in the shoulder, a driveway to a farm house, whatever. And then I get as far off the road as I can. Usually you can find something within a mile or two.
posted by JackFlash at 10:14 AM on November 30, 2019 [4 favorites]


To clarify use of hazard flashers, I'll turn them on if I'm driving very slow because of visibility and am actively looking for the nearest safe place to pull off the road.

Some people just slow from 70 MPH to 50 MPH and plan on just driving through with flashers on. That is a bad plan. If visibility is bad you need to get off the road, not just slow down and blast your way through with flashers on. That should be illegal.
posted by JackFlash at 10:43 AM on November 30, 2019 [2 favorites]


Official advice on this seems to vary. I've added the boldface and condensed the below quotes, which are about different weather conditions:

NWS on driving in thick fog:
In extremely dense fog where visibility is near zero, the best course of action is to first turn on your hazard lights, then simply pull into a safe location such as a parking lot of a local business and stop.
If there is no parking lot or driveway to pull into, pull your vehicle off to the side of the road as far as possible. Once you come to a stop, turn off all lights except your hazard flashing lights, set the emergency brake, and take your foot off of the brake pedal to be sure the tail lights are not illuminated so that other drivers don't mistakenly run into you.
Edmunds.com on driving in extreme conditions sections on Dust storms and Fog and Rain:
If you suddenly find yourself in a dust storm, follow the three "offs" of the [Arizona transportation] department's "Pull Aside, Stay Alive" campaign.

-First, turn off all your lights. "You don't want drivers thinking you're the car to follow as they are making their way through the dust," Nintzel says.

-Second, pull completely off the pavement. "You want to do so as quickly as possible, but it's important to pull as far off the highway pavement as possible," Nintzel says. This will help you stay out of any chain-reaction crashes.

-Third, after pulling off the road, put on your parking brake, but take your foot off the brake pedal. That way, your brake lights are not illuminated and other motorists will not follow the light and drive into you. Don't put on any interior lights or emergency flashers either, Nintzel advises.

"Dust storms tend to pass by rather quickly," he says. "So this is the best advice we can suggest: Keep your seatbelt on and be prepared to wait out the storm."


When heavy rain or fog catches you by surprise, the first thing you should do is slow down. [...and try to "see and be seen"]:

- [...] put headlights on low beam, Calkins says. Front foglamps can also increase your visibility. "They definitely help by producing a lower, flatter beam of light on the road's surface that helps you pick out road markings, Calkins says. If you have rear foglights [...] put those on as well. "What they are is an extra bright set of taillights that are more easily visible by the cars behind you," explains Calkins.

- if you have a pair of polarized sunglasses handy, put those on. "It doesn't work with every pair of sunglasses, and not the real dark ones. But a light tint or yellow-tinted driving glasses can sometimes help with your visual acuity under these driving conditions," Calkins says.

- to avoid fogged windows [...] run the heat and air-conditioning simultaneously. [..] Rolling down the window while driving in fog may help you hear what you can't see. [..]

- In these zero-visibility situations, finding a safe spot to pull off the road — with at least a 2-foot clearance — remains the best advice, he says. [...]

What not to do: Don't put on your high beams, which can scatter light and bounce it off rain and fog droplets, further decreasing your visibility and blinding oncoming motorists. And don't put on your four-way flashers/emergency lights, which are illegal to use in most of the country as you drive. Put on your emergency flashers only when you've pulled safely off the road.
The advice is for dust storms make your car invisible, but for rain/fog make it visible - I'm curious what's driving the difference there. Maybe that dust storms come up and pass more quickly?
posted by LobsterMitten at 11:38 AM on November 30, 2019 [7 favorites]


Thanks for the question. It's been really nice to read some answers and find out I'm not alone having had this nightmare thing happen.

This is still like the scariest ten minutes of my life. Heading south in Kansas on a toll-road with no shoulders or exits or bridges or anywhere to go. The only good thing was that it was a very straight, very flat road. I could barely see the lines on the road five feet in front of the car. Slow down a bit, keep it between the lines, hope that everybody else is doing the same. Still some crazy people coming up and passing.
posted by zengargoyle at 2:01 PM on November 30, 2019 [2 favorites]


I believe what flabdablet was getting at with "my foot on the brake and the transmission in reverse" is related to the previous clause in the sentence - trying to be as visible as possible.

Yes, absolutely this. If I'm stationary and at risk of being hit from behind due to low visibility, then I want all available lighting on the back end of my vehicle to be ON. The idea that my brake lights would make me an attractive target strikes me as deeply implausible.

The main reason I've been arguing against the transmission-in-neutral thing is not because I think having the transmission in gear would glue my vehicle to the road surface, but to reassure people that lighting up their reversing lamps will not increase their risk of bodily harm if the worst comes to the worst.
posted by flabdablet at 1:34 AM on December 1, 2019


And don't put on your four-way flashers/emergency lights, which are illegal to use in most of the country as you drive. Put on your emergency flashers only when you've pulled safely off the road.

I do fully agree with this advice. What hazard flashers should mean is "Here are the corners of a stationary obstacle". That's what the same colour of lamp flashing at the same kind of rate means when attached to temporary road signage, etc. And when the air is thick enough to make the flashing lamps the first perceptible thing about an obstacle ahead, the principle of minimum danger through least surprise says that that obstacle really ought to be stationary, even if the lamps in question happen to be attached to a vehicle.

The more people who drive down the road with their hazard flashers operating, the less reliable and less safety-promoting this meaning becomes for the driving population as a whole. This is the rationale for rolling with hazard flashers on being illegal in most jurisdictions.

Because hazard flashers generally re-use the same lamps as turn indicators, having your hazard flashers on also makes your turn indicators completely useless.
posted by flabdablet at 1:50 AM on December 1, 2019 [1 favorite]


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