Driving in fog: when to use fog lights

It takes no rocket science to understand that fog lights are the lights that need to be switched on in foggy conditions. Yet, it is not as simple as that. Both front fog lights and rear lights have their own functions and times to use. Most people struggle to understand when to use which light. In this guide, you will get to know how fog lights are the safest choice while driving in inclement weather.

What Are Fog Lights?

Fog lights, in layman’s terms, are the lights to be used in foggy conditions. However, technically, they are low-beam lights that provide a short-range illumination with a wide and low light cutoff.

For this property, they are used to aid visibility in fog and other low-visibility conditions, where strong illumination at the front of the vehicle is essential. Usually, fog lights use H11 bulbs, which typically have a halogen light source. These bulbs have a PGJ19-2 base and operate at 55W.

More often than not, fog lights are confused with the headlight bulbs and DTR lights. In fog lights vs headlights, it is assumed that when headlights are enough for the illumination job, why use fog lights?

Contrary to the common perception that more light means better visibility, in fog, excessive light creates glare. Using high beams in fog can reduce visibility because the light reflects off the fog or mist.

Therefore, fog lights are a necessity to combat reduced visibility in poor weather conditions. They enhance the safety of motorists on the road in challenging circumstances.

What Is the Fog Light Symbol?

Fog light symbols are the icons commonly found on the buttons located on the dashboard or to the left of the steering wheel on the indicator stick. Their sole purpose is to indicate the location of the fog light buttons and inform the driver if the lights are on or off.

What does the fog light symbol look like?

The appearance of fog lamp symbols is universal. However, the front fog light symbol looks different from the rear fog light symbol. Here’s how the fog light indicator may look in your car;

Front Fog Lamp Symbol:

It is depicted by a half oval-shaped lamp pointing to the left. The left direction of the symbol denotes a forward orientation visually. In front of the oval are lines pointing diagonally. The three diagonal lines intersected by a wavy vertical line represent light cutting through fog.

Rear Fog Lamp Symbol:

It is depicted by a half oval-shaped lamp pointing to the right. This direction represents a backward orientation. In front of the lamp are three lines pointing horizontally straight. The three horizontal lines bisected by a vertical wavy line, which again represents light cutting through fog.

So, for a general understanding, the wavy line is meant to represent fog. Since both symbols point in opposite directions, a simple rule to remember is;

Rear fog light = points right
Front fog light = points left

Where do you see the fog light symbol in a car?

The location of the fog light controls is the same in most vehicles. However, the location can vary depending on the generation or model. Here are the common locations you can find the buttons in;

• Steering Wheel Stalk: On older vehicles, fog light controls are located on the indicator stalk.
• Dashboard Panel: In newer vehicles, the fog light can also be controlled through a knob on the panel directly under the air conditioning vent.
• Infotainment Screen: In modern cars, the controls for fog light bulbs appear on the infotainment screen. They don’t have physically separate buttons for these lights.

If you don’t find your fog light switches where we have told you, check your owner’s manual.

When and How to Use a Car’s Fog Lights?

Although fog lights are meant to be used in poor weather, you cannot turn them on just like that. Not using fog light bulbs under the right conditions can cause hazards rather than enhancing security.

Fog lights are designed to be employed in any condition that obscures visibility. Thick fog is one use case that calls for turning the fog light bulbs on. Other conditions include heavy rain, snowfall, highway mist covering the road, even dust or sandstorms, and any situation where visibility drops.

However, since the extent of visibility can be subjective, the UK Highway Code has specified the conditions for using fog lights. Under code 226, it states that fog lights  MUST only be used when visibility is severely reduced. It is typically when you cannot see more than 100 meters ahead.

Law and Regulation

There are different requirments by the law regarding fog light bulbs. They are stated below;

• Having front fog lights is not a legal requirement in various states. However, if a vehicle has them, it is then a legal requirement that they should only be used in severe visibility conditions.
• All cars must have at least one rear fog light as it is a legal requirement in the UK. In the US, both front and rear fog lights are optional.
• It is not allowed to use a fog light as a primary light source in normal weather. This occurs because fog lights can’t illuminate far enough ahead when driving at highway speeds.
• In the Road Vehicles Lighting Regulations 1989, it is stated that using lights that dazzle other motorists is unlawful. So, using the fog light in normal conditions is dealt with strictly.
• The Highway Code states that you must switch off fog lights when visibility improves to avoid dazzling other drivers. Code 236 states that you MUST NOT use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves.

Where Are Fog Lights on a Car?

In the car, front fog lights and rear fog lights have specified positions. Front fog lights are mounted lower than headlights to illuminate the road directly in front of the vehicle.

Rear fog lights are located in the taillight cluster of the vehicle, either on the driver’s side or both sides. They use very bright bulbs to alert other road users to their presence in poor visibility.

Front vs Rear Fog Lights Function

Front fog lights illuminate the path in front of the vehicle. So, their function is to help you see and aid visibility. In the car, front fog lights are represented by a left-sided green lamp icon with a wavy line through it.

Rear fog lights use a concentrated beam of red light. Their function is to help other cars see you. Rear fog lights are represented by a right-sided yellow or amber lamp icon with a wavy line through it.

What is the 100-meter Visibility Rule?

It is a driving code defined by the UK Highway Code to ensure the safety of drivers on the road. According to the rule, if you can see clearly beyond 100 meters, there is no need to turn on fog lights. There are two aspects about it;

• If you keep the lights on despite having visibility beyond 100 meters, it can dazzle the oncoming traffic. So, drivers must switch off fog lights when visibility improves.
• If you keep the fog lights off despite having a visibility range of less than 100 meters, everyone on the road will be at risk.

Why is It Dangerous to Leave Fog Lights On?

Every car light has its own use and situation to be used in. When front lights for fog are left on without challenging conditions, they become dangerous. Here’s why neither the front nor the back light should be left turned on.

• Incorrect use of fog lights can obscure the brake light and dazzle other vehicles.
• The white light of front lights can produce glare for the road vehicles coming from the other side.
• In clear weather or conditions, using fog lights is considered illegal in various areas. So, using fog lights when visibility is not reduced can result in a fine from the police.
• Fog lights don’t provide extra illumination. Thus, using them instead of headlight bulbs will reduce your ability to see the road ahead.
• In drizzle or on wet road surfaces, it is advised not to use fog lights because the intense, low-mounted beams reflect off the water.

What Makes High-Quality Fog Light Bulbs?

The quality of light bulbs cannot only be judged by brightness. It is also influenced by the technology used to make them, as well as their housing and heat control. The following are the factors that make the fog light bulbs high-quality for modern cars.

• Optical Alignment: In high-quality bulbs, the light source is engineered to be a 3D position. This location ensures that the light produces a wide, flat beam with a sharp upper cutoff.
• Consistent Concentration: Premium fog lights also provide a light beam with a consistent concentration throughout their lifetime.
• Controlled Light Output: Many manufacturers market higher brightness as good quality. A quality bulb produces controlled light within 2000 – 4000 lumens. An excessively bright bulb is likely to produce dazzle for other road users.
• Thermal Management: Premium-quality fog lights feature baseboards made from aluminum or copper. They are efficient conductors that pull heat away from the chips to ensure maximum lifespan. It is contrary to the regular lights that often undergo overheating.

What Should You Do If Your Fog Lights Are Not Working?

Front fog lights and rear fog lights both withstand the inclement weather while illuminating the road ahead for you. However, they are also prone to undergoing different issues. In this section, we will expand on what are the common fog light problems and their solutions.

• Flickering: Your fog light can flicker or become dim due to either moisture buildup or aging. It is especially true for halogen bulbs, as they lose their brightness with time. Moreover, most vehicles have CANbus system that can trigger the flickering of low-resistance LED-based lights.
• Heat Damage: Low-quality fog lights are also damaged due to excessive heat when used for a long time. It happens because of poor housing material.
• Patchy Beam: Another problem is an uneven beam pattern. It occurs due to misalignment of housing or the wearing out of reflectors. A patchy beam can affect the visual of other road users.

When your fog lights stop working, you can follow two courses of action. If you are a daily commuter, you can get them repaired. Contrarily, for commercial vehicles and fleets, working fog lights improve visibility and help other drivers see them.

So, they must get their front and rear fog lights replaced when damaged. CarLightVision offers premium-quality fog light bulbs that last for a long time. You can trust them for bulk orders of fog lights for your fleets.

How to Choose the Right Fog Lights for Your Business?

Choosing the right front and rear fog lights is important for the safety of your fleet on the road. Whether you run a travel agency or a car rental service, saving a little on cheap fog lights can lead to costly damage later. So, we will tell you how to choose the right fog lights for your business.

What Should Buyers Look For in Fog Lights?

The following features set high-quality fog lights apart from the cheap ones. Look for these features to make sure your investment yields a long-term value.

• Durability: Choose the lights that are known to have longer lifespans. When it comes to life expectancy, LED outlasts halogen and HID options. So, look for good LED-based fog lights to reduce your replacement cost.
• Compatibility: Also consider whether the variant you are choosing is compatible with your vehicle’s model. Match the mounting requirement and identify the socket type.
• Waterproof: Look for designs that have an IP-67 rating. This standard ensures that your fog light will remain protected under harsh conditions.
• Certification: Opt for the options that meet the DOT/ECE regulations of your region.

OEM vs Aftermarket Fog Lights: Which is Better?

Both OEM and aftermarket fog lights have their own features and pros. The option you may choose depends on the features you prioritize. However, as a general rule of thumb, OEM fog lights are better than aftermarket fog lights.

Here’s a table that compares the features of OEM and aftermarket foglights.

Conclusion

Fog lights are not just any lights that provide illumination in fog. They are special lights that can produce a focused beam with the ability to cut through heavy spray or fog. They are also mounted at specific positions on the car.

Unlike headlights that just light up the road, their purpose is to enhance safety for you and other drivers. So, you must choose high-quality fog lights from trusted suppliers that offer a warranty and certifications, such as CarLightVision.

Get Bulk Fog Lights with OEM Customization by CarLightVision

CarLightVision has been providing full-service OEM/ODM customization for 15 years. We have a 7-step quality inspection system to ensure we produce premium quality fog lights. With around 70 highly qualified R&D staff, we produce new car light designs every month.

So, if you are looking for car lights for your business, we can help you decide. Contact us now and get a discount on bulk orders.

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