So When SHOULD You Drive With Headlights On? It’s More Often Than You Think!

Knowing when to use your low-beam headlights is all about safety…  Forget the rules that you’ve seen in state drivers manuals; regrettably they are seriously inadequate on quite a few important topics!

A road sign / traffic sign in Massachusetts, advising drivers to keep headlights on at all times.
See?  It’s official:  Headlights on at all times for safety!  Unfortunately, this sign in Massachusetts applies only to one section of a single road. (Nevada has more.) However, the advice it gives is actually true everywhere and at all times.  (Copyright image, 2017.)

Here in the USA, turning on the headlights commonly has only two causes:  The first is the time at which they must be switched on in relation to sunset and can be turned off again in relation to sunrise.  The second criterion is that in most states, if not all, headlights must be switched on whenever there is any rain and the vehicle’s wipers are being used.  But in terms of good safety neither of these rules is adequate.

The next photo is one of the 15 that appear in random rotation as the big images on our Home page, but look at it more carefully, here.

Vehicles silhouetted by the sunset;  Interstate I-90.  (Copyright image, 2019.)

If you noticed only three vehicles in the sunset photo, above, then you missed one — there are four.  The fact that the fourth one is at the right-hand side of the two visible red lights, going away from the camera is irrelevant.  The photo shows that a vehicle can easily be hidden from sight in contrasty lighting conditions at any time of day.  (Dark shadows from hillsides, trees or buildings on bright sunny days can have the same effect.)

A massive mistake that many drivers make is to believe that headlights are only to help you — the driver — to see better at night, but that is simply not true.  They are also there to make your vehicle more conspicuous so that other road users can see you coming in plenty of time, in almost any conditions.

And as for that “wipers on, lights on” thing, there are plenty of times when the day can be bright while it is raining or alternatively it can often be gloomily dark when it is not raining, so that is a very poor rule.

People who drive with their head in the proverbial (rain) clouds are often a danger to others. This driver was oblivious to the fact that everyone else was using their headlights and was therefore visible. Even if this person was apparently looking at the road ahead, they were clearly not thinking at all about what was happening. And that is a serious but invisible form of distracted driving. (Copyright image, 2016.)

Sometimes when you see a car with no rear lights, like the SUV in the photograph above, their front lights are on but the back ones are not (although in this case none were on), even in total darkness in the middle of the night.  This happens due to a combination of two reasons:

Firstly, Daytime Running Lights [DRL] are designed to minimize the electrical output of vehicles in order to save an extremely small amount of fuel (for valid environmental reasons).  However, in what we suggest was as an extremely unsafe decision, some automakers decided it was therefore alright to rig the lighting so that low-beam headlights, in DRL mode, operated on reduced power and rear lights were turned off altogether.  The result was and still often is that cars can be seen being driven at night as shown below — front white lights on but rear red lights off, and the potential danger from this is self-evident.

A classic, nighttime danger directly due to automakers wiring Daytime Running Lights [DRL] to exclude the rear lights, and drivers who don’t care enough to have EVER checked their lights. (Copyright image, 2017.)
Secondly, many drivers have never been properly told about DRL and have never bothered to check their car or the handbook about safety.  Those same drivers might also have noticed that their dash lights don’t work at night and as a result they can’t read the instruments (which is a function of some DRL systems but not others) but presumably they’re either baffled or just not bothered and keep on driving regardless.

An SUV in thick fog but displaying ony Daytime Running Lights [DRL]. It would have been more conspicuous and much safer to turn on the regular low-beam headlights.
On only Daytime Running Lights [DRL], this SUV was much less conspicuous than it would have been had the driver had the knowledge and or the sense to put regular low-beam headlights on. (Copyright image, 2018.)
So what is the safer alternative to all these unexpected dangers?

Well, in Sweden the safety engineers got their heads around the issue around the end of the 1960s and it was made law that all cars had to display low-beam headlights all of the time when being driven — 24/7, and whatever the weather.  Perhaps this is one of the reasons that from around that year until now, Sweden has been one of the two most consistently successful nations in terms of cutting road deaths.

So, how do you and your loved ones maximize safety when driving, in terms of being seen in plenty of time?  Simple:  Use low-beam headlights at all times, every time you drive.  And we don’t even mean automatic headlights either; they cannot sense — for example — the dangers of contrasty lighting that was mentioned at the start of this article.  Be the author of your own safety destiny; turn your low-beams on before you move off, every time, then turn them off at the end of your journey.

Does that go against the environmental motivation for having DRLs?  Yes, sadly it does.  But since when has a person’s life been worth less than a tiny amount of extra fuel?

A related issue comes with when you should and should not have your front fog lights turned on, but that topic will be covered in a separate post.


Please let us know, below, if you have any comments or questions about this issue.

6 Replies to “So When SHOULD You Drive With Headlights On? It’s More Often Than You Think!”

  1. Thank you for this post. Black vehicles are especially not seen in many conditions, especially rain. Against the black pavement and darkened sky they just disappear.

    1. Thank you for your comment, Sondra. You are right about black cars; in conditions of deep darkness or black shadows they can be very hard to see. In conditions of poor light, such as fog, or dawn and dusk, it can be pastel-colored cars that become hard to see, especially grey and tan/beige vehicles.

  2. I will have to make a couple adjustments. I do use full headlights on low in many instances, especially country roads or long high or low contrast roadways. I also use them on high traffic holidays. I need to adjust to ALWAYS.

  3. Why cant the united states simply mandate lights on all the time and have automakers make this a non option on all future made cars? lights on front and rear simply save lives.

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