Having lights on is good advice, especially since you tend not to notice the evening getting darker gradually. If you've been outside since daytime, by the time you realize to turn on the lights it's already quite dark. In my country, all new cars need to be equipped with daytime lights and even before that rule, using lights at all hours has been mandatory.

However, this advice is a bit questionable:

"Flashing LEDs (front and rear) are especially effective for cyclists as they create contrast and the on-off flashing attracts the peripheral vision in the same manner that movement does."

Flashing LEDs as your only light is really bad, because it's impossible to judge distance and speed from a flashing light in darkness.

Having a flashing light on your helmet or handlebars in addition to a normal light may be beneficial but only if you have otherwise decent lighting on your bike.

In fact, in my country there are regulations that require a non-blinking white light on the front, a non-blinking red light on the back and reflectors on the pedals and wheels. There are actually quite strict rules where and how the lights should be placed.

Unfortunately not everyone complies with these regulations, and the worst offenders I see are children. I've seen kids riding bikes dangerously on the roads (and had closer calls than I'd like to) on otherwise affluent neighborhoods. Their parents (and themselves!) had completely neglected to put lights on their bikes (or check that they work, have batteries, etc).

Long ago, running as twilight came on, I noticed something odd. Those driving east had the sun behind them, and were more visible, yet they had their lights on because they were facing a darker sky. Those driving west were less visible against the darkening background, yet they faced a lighter sky and did not turn on their lights.

Turns out I always turn lights on in such HDR situations producing low-contrast areas: if you have a hard time seeing those in front of you, those behind you have a hard time seeing you. Same goes for haphazard tree shades, even though it looks like it's bright enough, the alternating areas of bright and dark makes you difficult to see. Also, I have excellent eyesight which biases me into what is seeable and what is not, but I try to take into account those who don't, and act accordingly.

It's actually mandatory in most (if not all?) of the EU. You must have your headlights on at all times.

Definitely not all of them, Austria even rolled back because it removed the visibility advantage of motorcycles and because daytime running lights are an arms race that some legal road users cannot keep up with. It makes those with no light (or with significantly weaker lights) practically invisible because drivers will inevitably reduce attention to the common case.

If your car cannot be operated legally, it should not be operated. You don't need automatic DRLs, you can always just turn your lights on.

I think usrusr is referring to non-car road users. Bicycles and motorbikes need to stand out from cars, but can't keep up with them in a lighting arms race due to power and weight.

And ox-carts. And walkers. And all kinds of other long tail surprises. The distinction between limited access roads and the regular kind exists for a reason.

I think it's mandatory that new cars have always-on lights, rather than being mandatory to turn on your lights all the time (if you've got an older vehicle). That's how it is in the UK, anyway.

Mandatory for cars type-approved after the 7th of February 2011 [1], not all new cars. Some manufacturers were selling models that were type-approved before that date for years later (the Peugeot 3008 is one example), and therefore weren’t required to have DRLs.

1: http://europa.eu/rapid/press-release_IP-08-1394_en.htm

Motorcycles maybe, cars have (by now) mandatory daytime running lights, but at least in Germany for older cars it's not mandatory to have lights on during daytime.

Worse, some of the daytime running "lights" are only visible from about 5 m directly in front of the car - plus on most cars, the "daytime lights" setting only switches front lights, leaving the back entirely off. That's a cure worse than the disease.

I remember that one country reverted its decision for mandatory daytime light for cars because it decreased visibility of motorbikes (for which daytime lights were mandatory).

That would be France. The idea is indeed to increase visibility of the most vulnerable vehicles. Motorbike riders behave differently than car drivers, hence it is critically important to be able to distinguish them easily in traffic (we downright suck at evaluating movements of light sources compared to solid objects). This is also a factor as to why always-on daylights are mandatorily placed lower than headlights.

In Croatia it's only during winter time for cars.

The EU has required DRL's on all new cars since 2011. As an EU member state this applies to Croatia too.

That may be so, but on older cars you don't have to turn on your low beams when it is daylight savings time.

I reckon a dynamo hub and good always-on lights is perhaps the best cycling purchase I've made for my commuter bike. No faffing around with charging batteries and blinking lights, just leave it go all the time.

("perhaps" because mudguards are pretty useful too). b&m lights, sensible ones that have a backreflector so you don't get horrible specular lights shining in everyone's eyes.

This is always my pet peeve. If there's a car coming, and I'm trying to cross, I can see there's a car coming. Simple. But if there's 10 cars coming, and most of them have their lights on - the one that doesn't looks like a gap.

I don't care if you need your lights on or not. If >50% of traffic have their lights on, I need your lights on too.

There was a lot of debate about this when daylight running lights where made mandatory on all new motorcycles in the EU.

Most of it was on the lines of if every vehicle had lights on you would no longer stand out, you are just another light which is also harder to judge distance in the mirror. Where as if yo have lights on but cars don't you are more likely to stand out for thr fact there's less motorcycles so not as many lights to blend in to the background.

In the AU everyone genrally has full beams on regardless, horrible experince driving at night.

They are not there to stand out, they are there for you to see an object that exists specifically at a point x. Are you instead proposing the situation where half of the drivers are invisible and the other half is (probably) safe?

Just as much as you shouldn't be driving into a motorcycle you should probably not drive into a car.

All in all: you're saying is a horrible experience, but you're not giving any better solutions.

I don't think you understand what's being discussed here.

Some countries force their car drivers to always have their lights on.

The fact that some idiots think it's the same as driving with the high beams on all the time is absolutely different.

> if every vehicle had lights on you would no longer stand out

From reading this article I don't think that applies. It's typically only one car or bicycle that needs contrast against the background so that you don't miss them. It's not about trying to pick out one car amongst a sea of other cars.

Even then as long as you're aware there's something there you can avoid the psychological problem of assuming nothing is there.

Effectiveness of daytime motorcycle headlights in the European Union, 43 page report https://www.swov.nl/sites/default/files/publicaties/rapport/... .

In the summary section it says the conspicuity of motorcycles is improved with daytime lights although may be less if cars have daytime lights.

It’s been a long time since I read that report but it has lots of real data and research.

Cars are easier to spot regardless of lights due to them being much larger than a motorcycle or cyclist and the reports being biased towards protecting the most vulnerable road users.

Interesting, thanks for the link.

Your comments don't seem to answer the question of cars having their lights on making it harder to spot motorcycles.

At night time cars will have lights on anyway, so I think it comes down to if cars having their lights on makes it harder to spot a motorcyclist in traffic.

Doesn't it also apply the other way though? Motorcyclists are more likely to spot cars with lights in their periphery? I don't know how much of a non-issue it would be given how restricted the view is from a motorcycle helmet.

More reading, although I'm having difficulties getting links for pdfs:

"Motorcycle Conspicuity and the Effect of Fleet Daytime Running Lights"

> The annual number of motorcycle rider fatalities in the United States has more than doubled from 2294 in 1998 to 5290 in 2008 (National Highway Traffic Safety Administration, 2009). Many multi-vehicle motorcycle crashes involve right-of-way violations where another vehicle turns in front of, or crosses the path of an on-coming motorcycle. Improving the frontal conspicuity of motorcycles with forward lighting may reduce these types of crashes. On the other hand, widespread use of DRL on passenger vehicles may reduce the safety effectiveness of daytime headlamp use by motorcyclists. Research is needed to address these questions. This study involved testing the Fleet DRL Hypothesis that widespread use of daytime running lights (DRL) among the motor vehicle fleet is associated with an increased risk for certain types of multi-vehicle motorcycle crashes. This hypothesis is based on the assumption that the conspicuity of motorcycles (which normally run with their headlamp illuminated all the time) is effectively reduced during the daytime when a high proportion of other vehicles have DRL illuminated. To test the hypothesis, crash data from Canada where DRL use is mandatory were compared to crash data from the northern United States where DRL use is not mandatory and fleet penetration of DRL has been modest. Based on several specific assumptions, we developed a set of ten testable predictions that follow from the hypothesis. We compared crash data from the Fatality Analysis Reporting System (FARS) for 24 northern United States for the period of 2001 – 2007 to fatal crash data from the Canadian National Collision Data Base (NCDB) provided by Transport Canada for the same years. Crash scenarios that were plausibly relevant to frontal conspicuity of the involved vehicles were defined as DRL-relevant. The proportion of DRL-relevant crashes was modeled by country, year, and whether the crash involved a motorcycle. We fit separate models for crash data that occurred in four groups defined by time of day (Day, Night) and location (Rural, Urban) of the crash. The results supported seven of ten predictions indicating that the Fleet DRL Hypothesis may be true for urban roadways (but may not true for rural roadways). These results suggest that there could be negative consequences for motorcycle riders of widespread DRL use in the vehicle fleet. For urban roadways especially, the proportion of two-vehicle fatal motorcycle crashes that are relevant to frontal conspicuity of the vehicles (DRL relevant) is higher in Canada than in the USA. This result and other related predictions verified by the modeling results support the Fleet DRL Hypothesis for urban roadways, that widespread use of DRL in the vehicle fleet increases the relative risk for certain types of multi-vehicle motorcycle crashes. This conclusion should be interpreted cautiously in light of some limitations of the analysis approach.

"The Effects of Motor Vehicle Fleet Daytime Running Lights (DRL) on Motorcycle Conspicuity"

> As a group, motorcyclists experience a high fatality rate, a significant number of which are attributable to right- of-way violations by other drivers. One factor behind the high crash rate is insufficient conspicuity of motorcycles, which is now of greater concern because of the increasing use of Daytime Running Lights (DRL) in the vehicle fleet. The hypothesis is that the additional lights on all vehicles will degrade the conspicuity of the previously unique DRL signal used by motorcycles. The main goal of the current study was to evaluate the effects of motorcycle conspicuity treatments on other drivers’ left turn gap acceptance. This study was comprised of three phases. In Phase 1, a test track study measured participants’ left turn gap judgment as a function of motorcycle DRL treatments. This study was designed to determine which treatments yielded the largest gaps, thereby making that treatment a good candidate for the on-road portion. No treatment was clearly better, so lighting systems currently in use on motorcycles were selected for the on-road study. In Phase 2, an on-road study measured gap acceptance, then followed up with intercept surveys of observed drivers. This phase included data collection in the United States (low fleet DRL use) and Canada (high fleet DRL use) in order to evaluate the effect of DRL use in the vehicle fleet. However, due to concerns about the comparability of the U.S. and Canadian data, the results are inconclusive, and additional research is suggested. In Phase 3, motorcycle side conspicuity treatments (retro-reflectors and marker lamp) were compared. Results indicated that there were no differences in detection distance between the treatments.

"Effects of 24-Hour Headlight Use on Traffic Safety"

> Effect of Automobile DRLs on Motorcycle Safety Minnesota law requires motorcyclists to use their headlights during daylight hours, and opponents of DRLs have argued that requiring headlight use for all vehicles could make motorcycles less conspicuous. A NHTSA study on this topic, Motorcycle Conspicuity and the Effect of Fleet Daytime Running Lights, is expected to be complete by the end of 2010.

> The findings of the 2008 NHTSA study regarding motorcycles were not statistically significant, and the 2004 NHTSA study found that DRLs reduced daytime opposite direction fatal crashes of a passenger vehicle with a motorcycle by 23 percent.

In Canada all vehicles since 1989 must have Daytime Running Lights. They come on as soon as you put the car in gear and take off the e-break. It's brilliant.

I have a car without DRL, and I always have my headlights on. However, in the daylight (the "be seen" mode), I always turn my headlight adjustment switch all the way down to prevent unnecessary glare for other drivers.