Driving in adverse weather conditions (226 to 237)
Rules for driving in adverse weather conditions, including wet weather, icy and snowy weather, windy weather, fog and hot weather.
Overview (rule 226)
Rule 226
You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves (see Rule 236).
Wet weather (rule 227)
Rule 227
Wet weather. In wet weather, stopping distances will be at least double those required for stopping on dry roads (see ‘Typical stopping distances’). This is because your tyres have less grip on the road. In wet weather
- you should keep well back from the vehicle in front. This will increase your ability to see and plan ahead
- if the steering becomes unresponsive, it probably means that water is preventing the tyres from gripping the road. Ease off the accelerator and slow down gradually
- the rain and spray from vehicles may make it difficult to see and be seen
- be aware of the dangers of spilt diesel that will make the surface very slippery (see Vehicle maintenance, safety and security)
- take extra care around pedestrians, cyclists, motorcyclists and horse riders.
Icy and snowy weather (rules 228 to 231)
Rule 228
In winter check the local weather forecast for warnings of icy or snowy weather. DO NOT drive in these conditions unless your journey is essential. If it is, take great care and allow more time for your journey. Take an emergency kit of de-icer and ice scraper, torch, warm clothing and boots, first aid kit, jump leads and a shovel, together with a warm drink and emergency food in case you get stuck or your vehicle breaks down.
Rule 229
Before you set off
- you MUST be able to see, so clear all snow and ice from all your windows
- you MUST ensure that lights are clean and number plates are clearly visible and legible
- make sure the mirrors are clear and the windows are demisted thoroughly
- remove all snow that might fall off into the path of other road users
- check your planned route is clear of delays and that no further snowfalls or severe weather are predicted.
Rule 229: Make sure your windscreen is completely clear
Rule 230
When driving in icy or snowy weather
- drive with care, even if the roads have been treated
- keep well back from the road user in front as stopping distances can be ten times greater than on dry roads
- take care when overtaking vehicles spreading salt or other de-icer, particularly if you are riding a motorcycle or cycle
- watch out for snowploughs which may throw out snow on either side. Do not overtake them unless the lane you intend to use has been cleared
- be prepared for the road conditions to change over relatively short distances
- listen to travel bulletins and take note of variable message signs that may provide information about weather, road and traffic conditions ahead.
Rule 231
Drive extremely carefully when the roads are icy. Avoid sudden actions as these could cause loss of control. You should
- drive at a slow speed in as high a gear as possible; accelerate and brake very gently
- drive particularly slowly on bends where loss of control is more likely. Brake progressively on the straight before you reach a bend. Having slowed down, steer smoothly round the bend, avoiding sudden actions
- check your grip on the road surface when there is snow or ice by choosing a safe place to brake gently. If the steering feels unresponsive this may indicate ice and your vehicle losing its grip on the road. When travelling on ice, tyres make virtually no noise.
Windy weather (rules 232 to 233)
Rule 232
High-sided vehicles are most affected by windy weather, but strong gusts can also blow a car, cyclist, motorcyclist or horse rider off course. This can happen on open stretches of road exposed to strong crosswinds, or when passing bridges or gaps in hedges.
Rule 233
In very windy weather your vehicle may be affected by turbulence created by large vehicles. Motorcyclists are particularly affected, so keep well back from them when they are overtaking a high-sided vehicle.
Fog (rules 234 to 236)
Rule 234
Before entering fog check your mirrors then slow down.
If ‘Fog’ is shown on a sign but the road is clear, be prepared for a bank of fog or drifting patchy fog ahead. Even if it seems to be clearing, you can suddenly find yourself in thick fog.
Rule 235
When driving in fog you should
- use your lights as required (see Rule 226)
- keep a safe distance behind the vehicle in front. Rear lights can give a false sense of security
- be able to pull up well within the distance you can see clearly. This is particularly important on motorways and dual carriageways, as vehicles are travelling faster
- use your windscreen wipers and demisters
- beware of other drivers not using headlights
- not accelerate to get away from a vehicle which is too close behind you
- check your mirrors before you slow down. Then use your brakes so that your brake lights warn drivers behind you that you are slowing down
- stop in the correct position at a junction with limited visibility and listen for traffic. When you are sure it is safe to emerge, do so positively and do not hesitate in a position that puts you directly in the path of approaching vehicles.
Rule 236
You MUST NOT use front or rear fog lights unless visibility is seriously reduced (see Rule 226) as they dazzle other road users and can obscure your brake lights. You MUST switch them off when visibility improves.
Hot weather (rule 237)
Rule 237
Keep your vehicle well ventilated to avoid drowsiness. Be aware that the road surface may become soft or if it rains after a dry spell it may become slippery. These conditions could affect your steering and braking. If you are dazzled by bright sunlight, slow down and if necessary, stop.
Driving in Adverse Weather: What You Need to Know for the Theory Test
The key principles are to reduce speed, increase your safety margin, improve visibility and anticipate sudden changes in road and weather conditions.
Use lights when visibility is seriously reduced
You MUST use headlights when visibility is seriously reduced. Front or rear fog lights may also be used in these conditions, but must be switched off when visibility improves.
Think beyond what you can see
Poor weather affects both your ability to see and other road users' ability to see you. Slow down, increase your following distance and keep your lights, windows and mirrors clear.
When should fog lights be used?
Remember the trigger: seriously reduced visibility. Fog lights are not for ordinary rain or simply because the weather is poor, and they must be switched off when visibility improves.
Wet roads need more stopping space
Wet roads reduce tyre grip and can at least double stopping distances compared with dry roads. Rain and spray can also make it harder to see and be seen.
If steering feels unresponsive
Water can prevent the tyres from gripping the road properly. Ease off the accelerator and slow down gradually rather than making sudden steering or braking inputs.
What changes in wet weather?
The key answer is less grip and greater stopping distance. Keep well back, look further ahead and be especially careful around cyclists, motorcyclists, pedestrians and horse riders.
Ice and snow demand gentle control
Avoid unnecessary journeys in severe winter conditions. If driving is essential, clear the vehicle completely before setting off and expect stopping distances and grip to be significantly affected.
Avoid sudden actions on ice
Use a slow speed, gentle acceleration and progressive braking. On bends, reduce speed before the bend and steer smoothly rather than braking or steering sharply.
Why are sudden actions dangerous on ice?
Ice gives tyres very little grip. Sudden braking, acceleration or steering can cause loss of control, so the safest approach is slow, smooth and progressive.
Strong winds can move vehicles
High-sided vehicles are particularly affected by strong winds, but cars, motorcycles, cycles and horses can also be blown off course, especially on exposed roads.
Expect sudden gusts
Be particularly alert when passing gaps in hedges, bridges or exposed stretches of road. Large vehicles can also create turbulence, so give vulnerable road users extra space.
Who is most affected by crosswinds?
High-sided vehicles are particularly vulnerable, but do not overlook cyclists, motorcyclists and horse riders. Turbulence from large vehicles can also affect them.
Fog reduces your safe stopping distance
Before entering fog, check your mirrors and slow down. In fog, you must be able to stop well within the distance you can see clearly.
Do not follow rear lights blindly
Rear lights can create a false sense of security. Keep a safe distance, use wipers and demisters, check mirrors before slowing and be prepared for vehicles without headlights.
What is the key fog rule?
You must be able to stop within the distance you can see clearly. This is especially important on faster roads where vehicles may approach quickly.
Hot weather can affect driving
Keep the vehicle ventilated to reduce drowsiness. Hot conditions can soften road surfaces, while rain after a dry period can make roads slippery.
React safely to glare
If bright sunlight dazzles you, reduce speed and stop if necessary. Do not continue at a speed that prevents you from seeing the road safely.
What can hot weather change?
Expect questions about drowsiness, glare and changing road surfaces. The correct response is to reduce risk and adapt your speed and driving to the conditions.
Remember Before the Theory Test
Don't Mix These Up on the Theory Test
Adverse weather questions often test whether you understand the difference between visibility, grip, stopping distance and vehicle control.
Driving in Adverse Weather: Theory Test FAQ
When must you use headlights in poor visibility?
You MUST use headlights when visibility is seriously reduced. The Highway Code gives a general visibility guide, but the key Theory Test principle is to recognise when you cannot see far enough ahead to drive safely.
When should you use fog lights?
Front or rear fog lights should only be used when visibility is seriously reduced. They MUST be switched off when visibility improves because they can dazzle other road users and obscure brake lights.
How does wet weather affect stopping distance?
Wet roads reduce tyre grip, so stopping distances will be at least double those required on dry roads. Keep well back from the vehicle ahead and plan further ahead.
What should you do if your steering becomes unresponsive in wet weather?
It may indicate that water is preventing the tyres from gripping the road properly. Ease off the accelerator and slow down gradually. Avoid sudden steering or braking.
What should you do before driving in snow or ice?
Clear all snow and ice from the windows, clean the lights and ensure the number plates are visible and legible. Clear the mirrors, demist the windows and remove loose snow that could fall onto other road users.
How should you drive on icy roads?
Drive slowly and smoothly. Avoid sudden acceleration, braking and steering. Reduce speed before bends, brake progressively on the straight and steer smoothly around the bend.
Which vehicles are most affected by strong winds?
High-sided vehicles are particularly affected, but strong gusts can also move cars, cyclists, motorcyclists and horse riders. Be especially careful on exposed roads and when passing large vehicles.
What is the most important rule when driving in fog?
You must be able to stop well within the distance you can see clearly. Do not let the rear lights of the vehicle ahead give you a false sense of security.
What should you do if you are dazzled by bright sunlight?
Slow down and, if necessary, stop. You should never continue at a speed that prevents you from seeing the road and other road users safely.
Why can rain after a dry period be dangerous?
The road surface can become slippery after rainfall following a dry spell. This can affect steering and braking, so adapt your driving to the changed conditions.
How can hot weather affect driving?
Hot weather can contribute to drowsiness, soften the road surface and affect driving conditions. Keep the vehicle ventilated and remain alert to changes in steering and braking.