Windshield wipers

[agentsteel53]

If you're on a long downgrade and keep your speed down only with the brake, it's possible to boil your brake fluid and have no brakes left, making your vehicle a danger to yourself and others.  It's rare, but it happens.  Keeping your speed down by shifting into a low gear eliminates that risk.

certainly, it is common sense to use engine braking, but that doesn't mean it needs to be a law. 

should there also be a law that says one must use windshield wipers in the rain?  it is a good idea to do so, but it shouldn't be codified. 

[kkt]

If you're on a long downgrade and keep your speed down only with the brake, it's possible to boil your brake fluid and have no brakes left, making your vehicle a danger to yourself and others.  It's rare, but it happens.  Keeping your speed down by shifting into a low gear eliminates that risk.

certainly, it is common sense to use engine braking, but that doesn't mean it needs to be a law. 

should there also be a law that says one must use windshield wipers in the rain?  it is a good idea to do so, but it shouldn't be codified. 

California Vehicle Code, section 26707, in part:

Wipers shall be operated under conditions of fog, snow, or rain and shall be capable of effectively clearing the windshield under all ordinary storm or load conditions while the vehicle is in operation.

Wouldn't you want a cop to be able to stop someone who wasn't using enough common sense as to use the wipers in the rain?  Then the law should say so.

[agentsteel53]

okay, it was a poor example.  (that said, I only use the wipers under moderate to heavy rain - for light rain, I find it a lot safer to not have anything waving in front of my face)

coasting should not be made illegal unless you're endangering someone by cooking your brakes.  I know damn well when I can, and when I cannot, drive safely with the car out of gear.  in many circumstances, coasting is completely safe.

[1995hoo]

okay, it was a poor example.  (that said, I only use the wipers under moderate to heavy rain - for light rain, I find it a lot safer to not have anything waving in front of my face)

coasting should not be made illegal unless you're endangering someone by cooking your brakes.  I know damn well when I can, and when I cannot, drive safely with the car out of gear.  in many circumstances, coasting is completely safe.

I fully understand what you're saying, but the problem from a practical standpoint, both for law-enforcement purposes and for sorting out liability in accidents and the like, is that trying to regulate it in the terms you've set forth doesn't work.

[agentsteel53]

then thank goodness I've never seen it enforced!  to take the car out of gear when decelerating (unless intentionally engine-braking) was one of the most instinctive things I ever learned about driving stick. 

it gave me some extremely good miles-per-gallon figures.  I was regularly getting 40-44 out of an '89 Escort with 241000 miles in it!

[1995hoo]

Well, realistically how would they enforce it anyway? How is a cop going to tell that you're coasting in neutral unless he's driving an SUV and can look down into your car and see you waggling the shift lever from side to side?

BUT can you agree with the point I was making that if this law is on the books, then there's no reason to give the road-test proctor an easy reason to flunk you over something trivial like this (and something that I think most manual-shift drivers do without even thinking about it, sort of as a bit of a reflex)?

[vdeane]

okay, it was a poor example.  (that said, I only use the wipers under moderate to heavy rain - for light rain, I find it a lot safer to not have anything waving in front of my face)

In my case, the wipers actually make the problem worse in light rain by streaking.

[Special K]

okay, it was a poor example.  (that said, I only use the wipers under moderate to heavy rain - for light rain, I find it a lot safer to not have anything waving in front of my face)

In my case, the wipers actually make the problem worse in light rain by streaking.

Time for new blades.

[agentsteel53]

Time for new blades.

in my case, it is time to scrub off the insects. 

[kphoger]

Now that we're totally off subject, wipers caked with snow and ice sometimes make your windshield worse than the snowstorm itself due to streaking, not because they're old blades.  I also usually forgo the wipers.  My washer fluid has RainX in it, which does at least as well as two black sticks swishing back and forth in front of me in all but the heaviest rain.

[signalman]

should there also be a law that says one must use windshield wipers in the rain?  it is a good idea to do so, but it shouldn't be codified. 

If that were a law I'd break it all the time.  I use Rain X a lot.  Often I don't use the wipers, even in heavy rain.  The rain just beads up and moves up towards my roof.  I'm a miser when it comes to power consumption in my car.  It's bad enough that in the rain I have to have my lights on and a/c on to keep the windows from fogging.  I figure keeping the wipers off is one load saved anyway. 

[Scott5114]

should there also be a law that says one must use windshield wipers in the rain?  it is a good idea to do so, but it shouldn't be codified. 

If that were a law I'd break it all the time.  I use Rain X a lot.  Often I don't use the wipers, even in heavy rain.  The rain just beads up and moves up towards my roof.  I'm a miser when it comes to power consumption in my car.  It's bad enough that in the rain I have to have my lights on and a/c on to keep the windows from fogging.  I figure keeping the wipers off is one load saved anyway. 

Does power consumption actually matter all that much in a car though? I was under the assumption that the alternator would be keeping the battery charged at all times anyway, and as long as you don't overload the system to the point the spark plugs are getting no power, it wouldn't make any effect how much electricity you were using. And saving electrical power doesn't improve fuel economy because the electrical generation is just a secondary side effect of the engine's power...Or do I have a hilariously wrong image of how a car's electrical system works?

[agentsteel53]

And saving electrical power doesn't improve fuel economy because the electrical generation is just a secondary side effect of the engine's power...Or do I have a hilariously wrong image of how a car's electrical system works?

there is definitely a power loss.  to experience it most, try turning your AC on in the middle of a hill climb.  you'll definitely get more sluggish; you might even get a downshift out of it.

[signalman]

And saving electrical power doesn't improve fuel economy because the electrical generation is just a secondary side effect of the engine's power...Or do I have a hilariously wrong image of how a car's electrical system works?

there is definitely a power loss.  to experience it most, try turning your AC on in the middle of a hill climb.  you'll definitely get more sluggish; you might even get a downshift out of it.

Yes, Jake is right.  The power loss is also very noticable in a 4 cylinder.  Also, a lot of my day to day driving involves short trips where I don't get much drive time to recharge my battery, so I try to minimize the load on my alternator; giving me more available power to recharge with.  Sorry, I should have clarified that point earlier.

[deathtopumpkins]

I was under the impression that the AC compressor was the only thing that drew power specifically from the engine and everything else just used power that was being generated already anyway just from the engine turning.

I've noticed in my car (4 cylinder engine) that turning the AC on results in my car barely maintaining 55 and cuts my fuel efficiency in half, and I cannot run the AC unless the engine is running - it won't come on on just battery. Turning on the lights or wipers or radio has no discernible effect on the car's performance and can be done on just battery.

Also, wipers on when headlights on is the law in many states, and some specify when raining as well.

[Scott5114]

I think the law is "headlights on when wipers on", else you'd need to have the wipers on when you drive at night

[1995hoo]

I think the law is "headlights on when wipers on", else you'd need to have the wipers on when you drive at night

Yup, although I think many states also have exceptions for when the wipers are being used for windshield-washer purposes or are merely being flicked on occasionally due to mist (you know, when there's not enough rain to use your intermittent wipers, but you still need to make them do a single pass periodically).

Around here I think the "lights on when wipers on" law may be disregarded even more than laws about using turn signals and allowing faster traffic to pass on the left.

[J N Winkler]

I was under the impression that the AC compressor was the only thing that drew power specifically from the engine and everything else just used power that was being generated already anyway just from the engine turning.

Not true--everything that is connected to the engine crankshaft by a drive belt does draw power from the engine, although I think the air conditioning compressor is the only accessory for which the idle speed is automatically adjusted so that the engine can continue running smoothly while driving the A/C at idle.  (If you turn on the A/C at idle, you should feel a thunk as the compressor clutch engages, and then see the tachometer jump about 100 RPM.)

The load other accessories apply to the engine varies depending on conditions:

*  Power steering--maximum effort (and thus maximum power draw from the engine) should occur only when the wheel is turned almost to the stop on one side or the other.  When the wheel is straight ahead, high-pressure fluid from the pump is supposed to be returned immediately to the reservoir, so that power steering applies at most a frictional loss.

*  Water pump--always runs.

*  Alternator--always runs, but the actual load on the engine depends on battery voltage (which is used as the measure of how far discharged the battery is).  Power draw from headlamps, tail and side marker lamps, etc. can be substantial (about 100 W overall on low beams).

In regard to windshield wiper use versus Rain-X, I use Rain-X extensively, to the point that I don't use my windshield wipers at all when moving at freeway speeds--air resistance acting on raindrops is sufficient to skid them right off my windshield.  One thing that helps considerably with visibility that I think most drivers neglect is to clean sun film off the inside of the windshield, especially if the car is stored outside instead of being garaged.  Sun film is difficult to shift and badly degrades visibility after dark.  Windex (blue solution), sprayed on heavily after carefully masking the dashboard with towels, is the gold standard; a lot of other household glass cleaners are wishy-washy and won't cut sun film.

[kphoger]

Windex (blue solution), sprayed on heavily

I get streaking when using paper towels.  What do you wipe with (and don't tell me toilet paper)?

[J N Winkler]

I get streaking when using paper towels.  What do you wipe with (and don't tell me toilet paper)?

No, not TP (eurgh).  I use secondhand cotton bath towels.  We have a bin full of them in the garage that is left over from the days when we still hand-washed cars (we have been taking our cars to Little Joe's and using spot-free rinse for about 15 years now), and I now use them for taking care of window glass.

[deathtopumpkins]

I think the law is "headlights on when wipers on", else you'd need to have the wipers on when you drive at night

Yes, that's what I meant to say. 

That was the law back in Virginia, I believe signs were posted at major roads entering the state, and I'd say a good 95% of drivers followed the law. It was wonderful compared to up here in Mass where if there is such a law it's not publicised and hardly anyone actually turns their lights on in the rain.

J N Winkler:
You may be correct, I was just going off of what my mother explained to me (she has little experience with cars made in the last 20 years but extensive experience working on classic cars) and what a mechanic confirmed when we were having battery issues a few years ago and what I've observed in the hundred thousand or so miles I've driven so far in my life.

I just assume that if I can run accessories off just the battery without the engine running, they draw power from the battery, and if I cannot run them off just the battery, the engine has to be running, they draw power from the engine.

[1995hoo]

I think the law is "headlights on when wipers on", else you'd need to have the wipers on when you drive at night

Yes, that's what I meant to say. 

That was the law back in Virginia, I believe signs were posted at major roads entering the state, and I'd say a good 95% of drivers followed the law. It was wonderful compared to up here in Mass where if there is such a law it's not publicised and hardly anyone actually turns their lights on in the rain.

....

Signs are posted in Virginia, although they could really be more effective if they said "STATE LAW" somewhere. The signs for the "Move Over" law have a black-on-yellow "STATE LAW" banner and then say, in black-on-white, "MOVE OVER OR REDUCE SPEED FOR STOPPED EMERGENCY VEHICLES." The headlight signs are simply black-on-white and say "HEADLIGHTS ON WHEN USING WIPERS." (Compare to the white-on-black signs that say "RADAR DETECTORS ILLEGAL.") I find the black-on-yellow "STATE LAW" banner makes a sign a lot more attention-grabbing, especially in an area near the state line when they're already posting a large number of signs with various state laws and the like such that it's easy to overlook yet one more.

It's funny, though, that you say Virginians follow this law. I find that all too many people do NOT comply with it and that the compliance rate is maybe 60% at best. But then, more and more often lately if I'm out on the road at night I see people driving around with no headlights on regardless of the weather, so I guess if people can't be bothered to use their lights at night it's irrational to expect them to do it in the rain. (Thankfully the "no-lights-at-night" crowd is a much smaller group than the "no-lights-in-bad-weather" crowd.)

[Scott5114]

Windex (blue solution), sprayed on heavily after carefully masking the dashboard with towels, is the gold standard; a lot of other household glass cleaners are wishy-washy and won't cut sun film.

Previous Googling on this topic turned up a car enthusiast forum that recommended "Stoner Invisible Glass" for this purpose. It is available in the car section of Walmart as well as most auto parts stores. I've had better experience with it than Windex.

[cpzilliacus]

Signs are posted in Virginia, although they could really be more effective if they said "STATE LAW" somewhere. The signs for the "Move Over" law have a black-on-yellow "STATE LAW" banner and then say, in black-on-white, "MOVE OVER OR REDUCE SPEED FOR STOPPED EMERGENCY VEHICLES." The headlight signs are simply black-on-white and say "HEADLIGHTS ON WHEN USING WIPERS." (Compare to the white-on-black signs that say "RADAR DETECTORS ILLEGAL.") I find the black-on-yellow "STATE LAW" banner makes a sign a lot more attention-grabbing, especially in an area near the state line when they're already posting a large number of signs with various state laws and the like such that it's easy to overlook yet one more.

It's funny, though, that you say Virginians follow this law. I find that all too many people do NOT comply with it and that the compliance rate is maybe 60% at best. But then, more and more often lately if I'm out on the road at night I see people driving around with no headlights on regardless of the weather, so I guess if people can't be bothered to use their lights at night it's irrational to expect them to do it in the rain. (Thankfully the "no-lights-at-night" crowd is a much smaller group than the "no-lights-in-bad-weather" crowd.)

Maryland (only recently) enacted a "move over" law, and compliance is not that great. 

But it's needed - I know personally a Maryland trooper who was forced to retire after his elbow was hit (and his body part was badly injured) by a truck mirror while he was out on a traffic stop on I-495 in Montgomery County.

[bugo]

okay, it was a poor example.  (that said, I only use the wipers under moderate to heavy rain - for light rain, I find it a lot safer to not have anything waving in front of my face)

In my case, the wipers actually make the problem worse in light rain by streaking.

Especially if you have old wipers.  If you have a good set of wipers, the streaking is minimal.