Why Do Cars Have Lights On During The Day?

Often, you will see cars driving around town with their lights on in the middle of the day; the question is, why do drivers do this?

In this article, we will dive into why modern cars have Daytime Running Lights and whether or not there is any benefit to keeping the headlights on all day.

Here’s Why Cars Have Lights On During The Day:

Daytime Running Lights (DRLs) increase a car’s visibility during the day. These small strip lights on the front of the car make it more visible to oncoming traffic. It is not a legal requirement in the US for all new cars to have DRLs. However, there are other countries where it is legally required.

When are Headlights Required on Cars During Daylight?

In the United States, there is currently no national law that requires you to have your lights on during the day. The law states that all vehicles must have two fully functioning headlights.

However, there may different practices in different states.

  • In Georgia and Tennessee, headlights need to be turned on 30 minutes after sunset and 30 minutes before sunrise. In both of these states, drivers need to turn their headlights on in poor weather conditions – such as fog, rain or the presence of smoke – when visibility is low.
  • In California, drivers need to keep headlights on during the day when driving on mountain roads. And, from time to time, there are road signs that instruct motorists to keep their headlights on for the next X miles.
  • In California and New York, and several other states, the law requires drivers to keep headlights on if the windshield wipers are on.

Most modern cars will have DRLs built in from the factory. It is also worth mentioning that if at any time during the day, it becomes difficult to see other vehicles, drivers should turn on the lights to not only see where they are going but also to become more visible to other motorists.

Even though DRLs are not compulsory in the US, there is no doubt that when there is bad weather, Daytime Running Lights would definitely help make your trips that little bit safer.

In what Countries must Cars have Lights On During the Day?

Currently, there is no law in the USA that requires cars to have DRLs or daytime running lights on cars.

However, most new cars come with these lights as standard from the factory. This is not only for functional purposes, but also to keep up with modern designs in the motor industry.

In Sweden, for example, DRLs have been compulsory since 1977 and from 2011 in the UK.

Here is a list of countries where Daytime Running Lights are mandatory:

  • European Union Countries
  • United Kingdom
  • Canada
  • Most Nordic Countries 

In European Union countries, it is compulsory to have daytime running lights fitted to your car; these should be on a separate switch from the fog lights or headlights.

In general, most countries do not make it compulsory for you to have these lights fitted. However, in most countries, you are permitted to have them either fitted from factory, or to have them fitted afterward by an approved installer.

It is also worth mentioning that you can have DRLs in the back of your vehicle as well. There are many newer cars that come with DRLss installed from factory that also have rear-facing lights.

It would be safe to assume that having both front and rear-facing daytime running lights would be the most beneficial and would see the most success as the vehicle is now visible from more angles.

What is the Reasoning Behind this?

The main reason why certain countries have made DRLs a requirement is due to the climate of that region.

As we know, Sweden has required the use of DRLs for decades. This would make sense, since Sweden is mostly covered in snow during the winter, and is known for their challenging weather patterns and driving conditions.

Therefore, having extra lights on during the day is something that would help you navigate those challenging conditions.

The United Emirates also has prolonged periods of rain and thick mist, which makes normal day-to-day driving a challenge for motorists. In this region, while DRLs are mandatory, it is good practice to keep headlights on during the day in these conditions.

Countries that legally require vehicles to have daytime running lights, have made this law not only for other motorists to be more aware of you, but it also helps pedestrians to spot your car well in advance. Thus, minimizing the risk of accidents or injury due to poor visibility.

Do All New Cars Turn Lights on Automatically During the Day?

Most new cars that are in the medium to higher-end price gaps have automatic daytime running lights. Even some of your cheaper variants will still have some sort of light that runs automatically.

However, as it is not a requirement in most countries, there are still various models and manufacturers that do not include it.

The aftermarket options for DRLs are limitless though, and if your car did not come with any, then a quick search online will give you many options to choose from.

Always ensure that when they are being installed, it is done by a professional. Incorrect wiring or a bad DIY job can cause many electrical issues in your car, and in the worst-case scenario, it could lead to your car catching on fire due to improperly sealed wires.

It is also worth noting that most new cars also have automatic headlight activation, meaning they have sensors that pick up when it is necessary to have the lights on or off.

In many cases, you can switch off this automatic function through the menu of the car or by toggling a switch, however, when it comes to DRLs, you will rarely find an option to turn it off. This is to ensure that the DRLs are always on no matter what, eliminating the factor of forgetting to turn them on.

Are There any Statistics to Support Using Lights During the Day?

Studies have been conducted to establish whether or not fitting DRLs will reduce the risk of accidents, and if they are actually useful at all.

Some of these studies were carried out in Canada and the UK.

  • After analysis, it was found that over a period of a year, accidents went down by at least 5% when cars were fitted with daytime running lights. 
  • And, over a time period of a year, the overall accident number went down between 3 and 5% since the DRL legislation was passed.
  • Over a longer time period, you will find that these daytime running lights will slowly but surely decrease the accident rates as cars are more visible.

In fact, most studies show that 24-hour headlights reduce the number of daytime roadside accidents significantly.

Here are the results from other studies:

  • 37% reduction in left-turn-related accidents and a decrease in multiple vehicle accidents in Denmark.
  • In Canada, there was over 11% reduction in multiple vehicle crashes.
  • Results across different studies vary, but some have shown a reduction in pedestrian accidents by 12% and a decrease in accidents involving motorcycles by 23%

Keep in mind that there are millions of cars on the road that do not have DRLs at all, so as we progress into the future, these cars will be worked out of the system until most of the cars on the road will have daytime running lights.

This could see the number of accidents decreasing even more.

Final Thoughts

Daytime Running Lights are very bright, as during the day, you would need to have a bright and clear light to be able to spot it in direct sunlight.

These lights do not actually illuminate the road at all, your actual headlight is still responsible for that function. DRLs are purely used for visibility purposes.

In most cases, these lights will turn on automatically as you turn on the car, and they will automatically turn off when the car is shut off.

Not only are these lights useful, but they also give the front of the car a more futuristic look.

Most car manufacturers have their own signature DRL design that you could spot from a mile away. The most noticeable are Audi and BMW, who have been using DRLs in all of their recent vehicles with great success.

Our conclusion is that there is no doubt that DRLs are useful for day-to-day driving, they make it easier to spot your car in bad conditions, and they also make your car feel more modern and sporty. 

You could drive your normal everyday route without these lights, but they could help you arrive safely more often if they were fitted.


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