Save thousands on vehicle repairs with Endurance.
Get a FREE Quote

The Science Behind Your Car’s Headlights and 7 Safety Tips for Driving

BY: Alex Perrone
Man taping off his headlights to polish them

Being a better driver can decrease a person’s chances of being involved in an accident on the road, but all too often, drivers choose to focus on bettering their skills behind the wheel above all else. While this is certainly an important aspect of being a good driver, it’s crucial also to learn the intricacies of how a vehicle works in the event of a mechanical breakdown so that you can handle temporary repairs to stay safe on the road until getting your vehicle to a shop.

There are many components within a vehicle that you often don’t think about as you’re moving down the road. One of the important components that activates, particularly when the sun begins to set or in limited visibility, are the headlights of a vehicle. While most people simply switch their headlights settings to automatic and allow them to flick on whenever necessary by themselves, it’s worth understanding how these parts work in the event you need to troubleshoot them.

To that end, learn everything you need to know about how car headlights work and how you can begin to troubleshoot problems on your own.

The Evolution of Car Headlights Over the Years

The thoughtless ease of using car headlights has not always been around, as the technology has evolved quite a bit throughout the years. The earliest version of automotive headlights was introduced at the end of the 1800s, though they weren’t powered by electricity as they are today.

New cars back in the day utilized lamps that were heated with acetylene or oil due to their rain resistance. While mirrors were placed behind the flame in an effort to project the light given off further in front of the vehicle, they weren’t strong by any means.

It took another few decades for the first vehicle lighting systems to use electricity as vehicle manufacturers had issues shrinking down the bulbs efficiently. Sealed beam headlights were not introduced until the late 1930s, though this was also when they became mandatory on vehicles in the United States.

When the first vehicle-mounted halogen lamps utilizing halogen bulbs were introduced in the 60s, however, the technology in headlights really began to take shape. This iteration of headlights provided drivers with great visibility from their light beams using both low beams and high beams, which helped to revolutionize the industry.

Finally, modern-day high-intensity discharge lamps (HID) were introduced in the 1990s and used an electric arc between two electrodes through an inert gas known as Xenon to produce the light encased in the bulb. These lights traditionally lasted three times as long as Halogen lights and utilized far less energy.

Audi, BMW, Ford, Toyota, and other popular brands have recently begun introducing LED or light-emitting diode-based headlights into the market, however, which is revolutionizing lighting technology at this very moment.

The Components of a Car Headlight

While the science behind how a car’s headlight systems work will be examined shortly, it’s important to understand the components as well. Most modern-day vehicles utilize the following in their beam systems:

  • The Housing: In the vehicle headlights system, the housing is just the casing that contains all of the finer components of the system itself. It is the plastic or glass part that surrounds and protects the inner workings.
  • The Standard Beam: The arguably most used part of the headlights system is the standard beam. These are either the halogen, HID, or LED lights in the system.
  • The High Beam: The high beams are also contained in the housing and use the standard beams, though they distribute the light differently.
  • The Turn Signals: These are smaller lights and are separate from the standard and high beams, being activated only when you turn on the turn signal.

How Does a Car’s Headlight System Work?

With the components outlined, it’s time to break down how the headlights actually work when the sun begins to set or when you flip the lights on manually. First and foremost, photoelectric sensors gauge the amount of light around the vehicle to determine whether or not the headlights should be activated.

From this point on, how headlights work differs depending on the type of bulb, but this article will only focus on the two most common: halogen and HID. Halogen bulbs contain a tungsten filament in the middle that is heated by electricity to a scorching 4,500 degrees.

At this temperature, the filament burns white hot and produces the light you see on the road ahead of you, focused forward via a reflector and projector lens. Halogen gas inside of the casing combines with the burned-off tungsten atoms and rebonds them to the filament in a recycling process.

On the other hand, HID lights work slightly differently than halogen lights. This type of bulb contains two tungsten electrodes on opposite sides. When the light is activated, a pulse of electricity creates a constant spark between the electrodes utilizing Xenon gas. The current is then stabilized, and the light it gives off is projected onto the road via the reflector and projector lens.

Different Types of Car Headlights

As mentioned, there are currently three main types of headlight technology used in cars on the road today: halogen, HID, and LED. Halogen has been phasing out in recent years due to the fact that those bulbs last a shorter amount of time than the latter two types, and there is much more wasted energy seen in those types of bulbs.

Recent Innovations in Car Headlight Technology

Light-emitting diode-based headlights are still relatively new to vehicles being manufactured today. Rather than using a tungsten electrode or filament as with a halogen or HID light, LED lights pass a current through a semiconductor in one direction, which results in light being emitted, at a typically brighter scale, in a more energy-efficient way than both the other ways. The only problem is that LED headlights are currently more expensive to manufacture and can be more difficult to replace.

Additionally, adaptive headlights are a new piece of general technology that have been introduced to the automotive market in recent years. Using sensors and special light units, this technology will automatically adjust the shape, brightness, and direction of light emitted from headlights on a car.

This is either done using a manual shutter built into the housing component that blocks the light emitted or by using a number of smaller lights rather than one big light, then turning them on and off as needed.

Maintenance and Troubleshooting Headlights 101

The most common problem seen on the light source of a vehicle is a blown bulb, which simply occurs due to overuse after many years. On a halogen or HID bulb, this occurs when the Tungsten atoms eventually heat the quartz casing enough that it cracks. To fix this, many modern cars allow you to pop the hood and simply reach in to replace the bulb yourself.

To keep your vehicle headlamp operating perfectly for years to come, focus on checking the strength of the light periodically to ensure the light bulb is not dying. Additionally, as you drive down the road, always watch to see if your driving beam appears to be flickering to the driver’s eye, as this can represent a problem with the electrical system, regardless of the type of headlight you have.

Adaptive lighting and LED-based headlights are far more intricate than older types and will likely require the touch of a mechanic to fix issues.

7 Safety Tips for Utilizing Your Car Headlights

As LED and adaptive lighting technology continue to make car lights brighter on the road, it’s important to learn how to use your lights responsibly. In fact, considering that the latter was just recently approved by the National Highway Traffic Safety Administration (NHTSA), it’s never been more pertinent. While the white light given off by modern headlights makes things easier for you to see, it can hinder oncoming drivers if you are not careful. Therefore, keep some of the following safety tips at the top of mind:

  1. Turn off your high beams when there are oncoming vehicles on the other side of the road
  2. Avoid using your high-beam headlights when only low-beam headlights are necessary, as this will deplete the lifespan of your headlights
  3. Turn your fog lights on when driving in inclement weather conditions
  4. Switch your headlight settings to automatic so that you don’t accidentally use the wrong setting
  5. Inspect your tail lights regularly to ensure they are working properly
  6. Ensure that the light output of your headlights aligns with NHTSA regulations if your headlights are after-market
  7. Don’t replace your halogen headlights or HID headlights with LED headlights if your vehicle cannot handle the switch

Protect Your Vehicle’s Components With Endurance

The headlight system on your vehicle is only one of many complex systems that exist within your vehicle. While you may certainly be able to troubleshoot and fix smaller problems within a car, it’s inevitable that a mechanical breakdown will occur at some point, which requires the touch of a mechanic to fix.

This often comes with a high price tag and can leave you feeling frustrated as your car is in the shop for an extended period of time. Having an extended warranty package can soften the blow, however, by providing monetary reimbursement for covered repairs.

Endurance Warranty offers customizable extended warranty contracts for you to consider depending on the needs of your vehicle. From basic coverage designed for older vehicles all the way up to near manufacturer-level coverage with few exclusions, there is a package for everyone with Endurance.

Additionally, all contracts come with standard parks like 24/7 roadside assistance, towing, and lockout services. For a small activation fee, new customers can get additional Elite Benefits, including $1,000 in total loss protection, $500 in collision discounts, and reimbursement for up to two tires per year due to road hazards.

To learn more about how Endurance can help protect your vehicle on the road, give our award-winning customer service team a call at (800) 253-8203 and request a FREE quote. You can also shop online to see your price instantly.

Get started with a FREE quote.

    • Select Year First...
    • Select Make First...
    Get a FREE Quote