Safe Driving in Fog

Written by John

On September 21, 2020

For some, driving in fog is not a pleasant experience. Others don’t mind it. But do your fleet drivers, who are driving lots of business miles, know what to do?

They could be travelling through all different types of weather depending on how far they must go. I recall starting a journey when I was training the RNLI: I had to go to North Wales to do one session over there. I set off in the early morning. It was damp and misty, but you could see a good distance ahead. This then turned to rain as I got to the motorway. I arrived at the RNLI station and set off to train a candidate round Snowdonia. Throughout the morning, we had rain, hail, strong winds, fog, and, as we went higher, a little snow.  After that I had to travel to the South East coast for another RNLI session. On my travels I had rain, sleet, then sun.

So you can see when you are on the road a lot, you must always be prepared for what may come. But fog is a tricky weather that seems to confuse many drivers.

When Do You Use Fog Lights?

You may think, “this is easy: when foggy.” If you ask a learner driver when should you use fog lights, you get a variety of answers such as: when foggy, when you can not see in front, 3 metres, 1 metre. So it is not so simple. But you may say they are learning and do not know. Ok, yes, but what about the drivers you see with them on when they are not needed or vice versa.

Do You Know When to Turn Them On?

A key confusion for many people is; what is the difference between mist and fog? The Met Office says that if visibility is less than 1,000 metres then it is foggy, if visibility is greater than 1,000 metres then it is misty. As a driver you need to know when to use them. When you’re driving in poor weather you should always use dipped headlights. When visibility is reduced to 100 metres (328 feet) or less, you should use fog lights. This is about the length of a football pitch. Therefore, you need a reasonably thick fog to use fog lights. This comes down to what fog lights are for. Fog lights are there to make you more visible rather than to enable you to see further ahead. Always remember in fog, reduce your speed.

Do All Cars Have Fog Lights?

Fog lights on the rear of vehicles are required by law in the UK. Front fog lights are not, but may be found on higher spec vehicles. Some have the daytime running lights instead; these are brighter LED lights you see on all new cars that are on all the time and designed to make your vehicle more visible. However, they can go off when you turn on your dipped headlights. Also, when you have your daytime running lights on, there are no lights showing at the rear. So, in bad weather use dipped head and tail lights. When you visibility is less than 100m (328 feet), use your fog lights.

How Do You Use Them?

Sometimes if you have not used them in a long while or you get a new vehicle, it is easy to forget where the switch is. Always spend some time getting familiar with your vehicle, looking at the switches, and reading the manual. This prevents you from suddenly having to figure out where things are when you are driving. They are normally on a separate switch to your dipped lights switch: it may be a different button on the dash and a light will display on the instrument panel to show they are on. If your vehicle has auto lights do not assume they come on in the rain or poor light as it may not be dark enough to activate.

If you are not sure where switches are never be afraid to ask for help. Local driving instructors will always help you understand a new vehicle or familiarise you with your vehicle if it has been a while.

What If You Forget to Use Them?

This is very dangerous. As you will be hidden from traffic behind you if you do not use fog lights when needed. Let’s look back to 2017, there were 16,404 incidents in rain, sleet, snow or fog on Britain’s roads, including 205 fatal incidents, according to the figures from the Department for Transport. Fog lights are there for your safety and the safety of others.

Why Turn Them off Then?

The Highway Code is very clear about this. It says:

You must not use front or rear fog lights unless visibility is seriously reduced as they dazzle other road users and can obscure your brake lights. You MUST switch them off when visibility improves.

As you can see the word MUST, misuse of the fog lights can result in a £30 fine.

What Else Can You Do When Driving in Fog?

To start, you should turn on your dipped head lights, this will show tail lights also. You should slow down so you can stop in the distance you can see clear and increase the gap between you and the vehicle in front in case of needing to brake harsh for something further ahead that you can not yet see. If it is really thick fog, you can open your windows at junctions or roundabouts to hear traffic approaching. But if conditions are really bad, you should consider: is your journey essential? Could you wait until the weather improves? Then, when the weather has cleared, remember to turn off your fog lights.

You May Also Like…

Safety Tips for Driving at Night in the Dark During Winter Months

Safety Tips for Driving at Night in the Dark During Winter Months

There is no doubt that driving at night in the dark is more dangerous than in clear visibility. A survey that was conducted by ROSPA in 2017 showed that 40% of collisions occur in the hours of darkness. The study  also found that falling asleep behind the wheel was...


Want to know how to stay safe on the road?

Download Our Six Daily Vehicle Checks Printout