Fog Light Guide: How & When to Use Them + Bulb Replacement Tips

INTRODUCTION

Living in an area with consistent weather or frequently encountering low visibility, fog lamps are a crucial component of your vehicle's headlights and serve an essential purpose when it matters most. Therefore, the requirements for their brightness and performance are constantly increasing. This article will concentrate on fog lights, when to use them, and how to install them, along with addressing common questions about fog lights. Let's explore this subject further to improve your comprehension of fog lights and promote safe driving.

WHAT IS A FOG LIGHT? 

A fog lights, also known as a front fog lights, is a type of automotive headlight that features a broad and downward-sloping low-beam pattern. This pattern is angled downwards to provide coverage over a wider area closer to the ground. At the top of the beam, there is a distinct cut-off line that prevents the light from spreading too far. This helps to minimize the reflection of fog or water vapor. By reducing glare and enhancing contrast, this design improves visibility in fog, snow, or rain, without causing discomfort to the driver's eyes. Consequently, fog lamps are well-suited for utilization in inclement weather conditions.

(Note that the symbols for front fog lights and rear fog lights do not match. The front fog light symbol is represented by a lamp with diagonal lines intersected by a wavy line to the left; while the rear fog light symbol is a light bulb with horizontal lines and a wavy line intersecting it as well.)

WHERE IS FOG LIGHT?

Fog lights are specifically created to enhance visibility during inclement weather conditions by illuminating the road ahead. Therefore, car manufacturers typically position front fog lights beneath the headlights, near the front bumper, in a lower location. This placement allows the fog lights to effectively penetrate through dense fog, heavy rain, and other similar conditions, while minimizing light reflection. This ensures that the driver can better see the road conditions ahead and the surrounding environment.

WHAT COLOR ARE THE FOG LIGHTS?

When it comes to choosing the color of front fog lights, there are typically two options: selective yellow light and white light. For yellow fog lights, the typical color temperature specification is in the amber or selective yellow spectrum between 2,700K and 3,000K. These lights have strong penetration and a minimal glare effect, allowing them to cut through fog and improve visibility. On the other hand, white fog lights have a color temperature of around 5500K-6500K. These cool white lights provide a brighter illumination and enhance the aesthetic appeal of the car.

Certainly, other manufacturers offer various color options for fog lights on fog light assemblies, LED fog light bulbs, and HID bulbs, including blue, purple, and so on. However, it is important to note that in the United States, only yellow and white front fog lights are currently permitted by law.

If you are interested in understanding why selective yellow fog lights produce less glare or are unsure about whether to choose yellow or white fog lights, you can refer to the article - Best Fog Light Color: Why Yellow?

WHEN TO USE FOG LIGHT?

Using fog lights correctly and following regulations is crucial for driving safely. So when should we use fog lights? Generally, fog lights should not be used in normal weather conditions because they are brighter and larger than standard headlights. Using them in normal conditions can blind other drivers and cause confusion, which is dangerous. According to the Highways Act (Section 226), fog lights can be used when visibility is less than 100m. Front or rear fog light must not be used unless visibility is severely reduced.

Hence, fog lights should only be utilized in situations where the road is affected by severe weather conditions like snow, dense fog, or sandstorms, resulting in significantly reduced visibility for the driver. They can also be employed when there is heavy fog on the highway. The reason behind this is that fog or mist reflects light, and relying solely on low beams in such circumstances would make it even harder to see the road ahead.

It is worth noting that it may also be against the law to simply activate your fog lights when driving in other weather conditions that impact visibility, such as fog. Based on the fog lights' beam pattern, the short and wide pattern is most effective in illuminating the ground and enhancing visibility at close range. However, due to the limited illumination of the road ahead, only part of the road can be illuminated. Therefore, it needs to be used in conjunction with low beam lights, which can improve the field of vision in bad weather, see the road ahead clearly, and allow other drivers to see it to ensure driving safety.

HOW TO REPLACE FOG LIGHT BULB?

After we have a comprehensive preliminary understanding of fog lights, you may be thinking about installation. In fact, the installation process of fog lights is also very simple, so there is no need to worry. The following is the installation process using a Toyota car as an example for your reference.

• Vehicle's Information: 2021 Toyota RAV4
• Installation Location: Fog Lights
• Product: H11 yellow LED fog light bulbs
• Tools Needed For The Install: Installation on the LED fog light bulbs is very easy, tools needed are just a clip removal tool and socket wrench to remove the fender liner.

Begin by replacing the fender liner on the driver's side. Take out a few screws and clips, specifically three in one area and two at the bottom.

Then utilize a screwdriver to remove the screws. Once all the screws are removed, simply flip the fender liner out and insert your fingers to pull it out, granting access to the fog lights.

Lastly, press the clip on the harness, pull it down, and twist it to detach. We were then ready to install the new LED fog light bulbs.

CONCLUSION

As auxiliary lights, fog lights are not commonly used in people's daily driving, but they play a very important role at critical moments. Especially in severe weather conditions, the characteristics of fog lights and the use of headlights can greatly improve our driving safety. It's better for you to understand the relevant factors and usage of fog lamps, so as to better exert the effect of fog lamps and ensure our driving safety.

FAQ

Question： Why is it illegal to have fog lights on during normal visibility?

Answer: The purpose of restricting the use of fog lights to specific weather conditions is to ensure the safety and comfort of all road users. Because fog lights are extremely bright and powerful and if used when there is no dense fog or falling snow can cause glare and dazzle other drivers, which is illegal under the road traffic lighting of vehicles regulations.

Question: Are fog lights on a car necessary?

Answer: Because fog lights are not mandatory equipment for motor vehicles under federal law, each state that uses fog lights can regulate them under its own laws. Though there is no uniform mandatory requirement for front fog lights in the Americas, in the case of severely restricted visibility, the front fog lights will also play a great role in helping. Therefore, it is necessary to consider whether to turn on the front fog lights according to the weather conditions in your area and personal needs. For safety reasons, I personally prefers to install the front fog lights as well. Readiness is all, have a second string to one’s bow.

Question: How can I prepare for a driving in fog?

Answer: Before driving in fog, make sure your mirrors are clean and wipe down the front and rear windshields. Top up with windshield washer fluid so you can use the wipers to keep the screen clean while driving. Then make sure you have a high-reflective jacket and a warning triangle with you in the car in case of an accident. Finally, when you approach fog on the road, check your mirrors and slow down for a safe start.

Question: When Should You Turn Your Fog Lights Off?

Answer: According to highway regulations, fog lights should be turned off when visibility becomes normal, or after a period of fog. This is because leaving the fog lights on can dazzle the driver in front of you. Including when the vehicle is parked, the front and rear fog lights cannot be turned on, otherwise you may be fined for incorrect use of fog lights.

Question: Is it illegal to drive without fog lights on foggy days?

Answer: It is not illegal to drive without fog lights in bad weather conditions. However, for the safety of the driving process and other drivers, it is advisable not to do so, as it is an additional safety measure. In addition, you have a legal obligation to use your headlights in foggy conditions. Also, make sure to ensure that you turn off your fog lights as soon as visibility improves or when you approach a vehicle traveling in the opposite direction.

Question: What light to use in fog？

Answer:

1. Low beam: When driving in fog, use your vehicle's low beam headlights. This is the single most important rule.
2. Fog lights use them with low beams, but do not use them instead of low beams: They supplement low beams, not replace them. Turn them off when visibility improves: Their wide, low beam can dazzle other drivers in clear conditions.
3. Rear fog lights (if equipped): Use them in conditions of severely reduced visibility (e.g., visibility less than 100 meters/yards).
4. What not to use in fog: High beam headlights (full beams). High beams project light far and high. In fog, this light reflects intensely off the water droplets and dazzles the driver, making it difficult to see the road ahead. Therefore, always switch back to low beams when entering fog.