Daytime running lights: what are they and why do you need them

2022 Hyundai Tucson
2022 Hyundai Tucson

Which came first, the chicken or the egg? We may never know the answer to this question, but there are others we need to address, such as whether you really need daytime running lights (DRLs). We’re a little more confident in the CSR question than the chicken or the egg, so we’ll give it a try.

Some governments believe that DRLs prevent accidents and have mandated their use on motor vehicles. These are usually governments sitting together in northern climates and wishing the sun would shine. For example, Sweden, Finland, Norway and Canada made CSR mandatory decades ago. However, the European Union also made them mandatory for most new motor vehicles by 2012.

So far, the United States government has refused to include the CSR cause, citing a lack of meaningful studies indicating that CSRs reduce accidents or save lives. It is much easier to define CSRs than to argue why you need them. Let’s start there.

What are daytime running lights?

Despite the government’s lack of action, most new passenger cars, SUVs, and light trucks sold in the US have CSRs. You can also hear them called ‘signature lights’. These low-wattage white lights activate automatically when you turn on the vehicle’s ignition. DRLs are often located around the headlights and are located on the front near the sides of the vehicle.

2022 Hyundai Tucson

2022 Hyundai Tucson

DRLs are the Baby Bear among the headlights. That is, they are neither too bright nor too weak. They are just right for illuminating the front of a car, somewhere between parking lights and low beams.

What is the purpose of daytime running lights?

The purpose of CSRs is not to illuminate the view in front of your car. Instead, they make your car more visible to the drivers and pedestrians approaching you. Therefore, they point forward rather than downward, as headlights and fog lamps do.

DRLs perform most effectively when the ambient light is dim — dusk, dusk, cloudy days, and so on. That is why Scandinavian countries, with notoriously short days, were eager to give them a mandate.

2020 Kia Telluride

2020 Kia Telluride

One unintended benefit (at least for car manufacturers) of CSRs is that they are another way of branding. That’s where the term ‘signature lights’ comes in. Audi pioneered the creation of a distinctive DRL pattern for most of its range. In addition, CSRs give your car or truck a more technical and expensive appearance.

How do you use daytime running lights?

Not much learning curve is needed here. DRLs all work on their own. They light up when you switch on the ignition and go out when the headlights are activated. The driver has no real control over the operation of CSRs because there is no CSR on/off switch.

2020 Kia Telluride DRL

2020 Kia Telluride DRL

Under limited circumstances, such as when parked with the engine running, your vehicle may provide a method of extinguishing the CSRs. However, the procedures differ from model to model.

Can you add DRLs to a car?

Yes, you can add DRLs to your vehicle if it doesn’t have them. We recommend that you do not do the work yourself unless you are an experienced DIYer. While installing a universal CSR system is not brain surgery and can be done in an afternoon, it is your car’s electrical system. Any misstep can have a negative ripple effect throughout the electrical system. In addition, the installation must comply with specific regulations for the location and direction of CSRs, both by you and by a professional installer.

If you choose to do the job, there are dozens of DRL aftermarket kits to consider. We recommend a universal kit that can be adapted to almost any car, truck or SUV.

How much does a DRL kit cost?

Do-it-yourself DRL kits are available online and at some brick-and-mortar stores. Expect to pay from $50 to $200 for a universal kit.

How Much Should DRLs Be Professionally Installed?

Here’s the less good news. In addition to the local dealer for your vehicle’s make, you may need to do some work to find a competent professional installer for your DRL kit. That’s not to say they aren’t there, but many auto shops just don’t have experience with the installation.

Your search efforts may pay off. Look for custom auto stores that specialize in outdoor lighting. Expect to pay around $750 in many parts of the country. That rough estimate of the cost would cover a $150 universal daytime running light kit and three or four hours of labor for the auto fitter.

The good the bad and the ugly

Now we come to the question of why (or if) you need CSRs. It seems intuitive that lighting at the front of a vehicle would help pedestrians and other drivers see it. However, the studies measuring their effectiveness during daylight are mixed. As mentioned above, the US government feels no obligation to make them mandatory.

What are the minuses?

  • Driver confusion – The most common complaint about DRLs is that they throw out enough lighting to fool some drivers into thinking their headlights are on when they aren’t. While oncoming drivers will still see you, and you will see them, CSRs don’t do much to light the road. In addition, if your headlights are not on, your taillights will not be either, posing a major safety risk in the dark.
  • Extra fuel consumption – Believe it or not, DRLs add to the load on the alternator, requiring more fuel to be burned to meet power requirements. This also means a bit more tension on the alternator. However, the extra gas and the extra load on the alternator are minimal and hardly worth discussing. In addition, most DRLs on today’s new cars are LEDs, which consume very little energy. Heated seats and heated steering wheels also take power from the alternator, requiring additional fuel.
  • They draw attention away from other things – Most motorcyclists drive their vehicles with illuminated headlights, regardless of the time of day. They do this with the belief that it makes them more visible to other traffic. Many of these same motorcyclists claim that the proliferation of CSRs distracts motorcycle headlights, decreasing their safety. Some anti-CSR advocates argue that all CSRs draw too much attention from other drivers, making them less likely to notice pedestrians, cyclists and other objects on the road.

What are the pluses?

Statistical Evidence – Despite the government’s position that there is not enough evidence to make CSR mandatory, there is some evidence. A 2010 publication from the Minnesota Department of Transportation stated that DRLs reduced daytime accidents from 5% to 10%. A 2008 study by the National Highway Traffic Safety Administration (NHTSA) placed the accident reduction rate with DRLs at 5.7% for light trucks and vans.

Dimmed Ambient Light – If there is enough light that you don’t need headlights, but the light fades, CSRs are at least somewhat effective. They can increase the chances of you seeing an approaching vehicle, especially a dark colored vehicle.

Insurance discounts – Some insurance companies can give discounts to drivers with vehicles that use CSR. Such discounts may vary by state.

They look cool – There’s no doubt about it, the current crop of DRLs is adding some spark to the face of cars, trucks and SUVs by making vehicles look more technologically advanced.

What is the future of daytime running lights?

2022 Chevrolet Silverado High Country Driving Lights

2022 Chevrolet Silverado High Country Driving Lights

There is no reason to believe that CSRs are going anywhere, whether the government changes its mind and makes them mandatory or not. Car manufacturers are always looking for economies of scale. That is, lower the price of a feature by installing it in more vehicles. CSRs are already relatively cheap, even in the aftermarket. It makes sense that manufacturers would continue to install them as standard on cars they sell in the US to keep prices down in markets that require CSR.

Our Take

We agree that CSRs are likely to help reduce accidents in low-light situations, such as cloudy days or twilight. However, we’re not sure if it’s worth the time and expense to install an aftermarket kit on your 10-year-old beater that doesn’t have it. On the other hand, we don’t see any real harm in having them, even if they don’t offer extra security. Mandated or not, they are here to stay for the foreseeable future.