Driving in floods and heavy rain

Heavy rain has left much of the South East subject to a Highways Agency flood warning or alert, so it’s essential that you and your car are prepared for driving in heavy rain and on flooded roads. Follow our guide and stay safe on the streets this winter.

Don’t underestimate the dangers posed by wet roads – driving in heavy rain or floods is hazardous and should be avoided as much as possible, but if you have no alternative, follow these tips to help ensure you remain safe.

Long Ques

While many vehicles – such as four-wheel-drive SUVs – are designed to negotiate relatively severe flooding, the water holds dangers that can leave even the largest car stranded and the occupants at risk.

Water and your car’s electrics don’t mix, which is especially bad news for petrol-powered vehicles with their complicated electronics. Moisture in your car’s wiring can result in a complete breakdown, or loss of essential systems such as lights, windscreen wipers and air-conditioning.

Driving through floods can also cause water to be sucked into the car’s engine – resulting in smashed pistons, damaged crankshafts and a written-off  engine. Merely an egg cup of water can destroy your car’s engine. All types of motors are affected by this, but turbo-charged and diesel units are most at risk.

Of course, these are just some of the risks to your car, but flooding can have far more dangerous consequences for the driver and passengers. Driving into flood water of just 12-inches can pick up your car and float it away.

So – avoid damage to yourself and your car – by following our guide to staying safe on sodden roads.

Don’t drive

This is the best advice for staying safe. If there’s any way of leaving your car at home in extreme conditions, then take it. Using public transport can be safer in times of extreme weather, with bus and rail companies having well-planned systems in place for just such times. However, ensure that trains and buses are operating before you pull on your wellies.

Driving in heavy rain

If you have to take the car, here are our tips for driving in heavy rain, and staying as safe a possible.

1) Plan your route: Choose a route avoiding areas that are prone to flooding. You’ll also need to drive at slower speeds, so allow more time for the journey. Tune into a local radio station, which will keep you up to date with weather conditions, flooding and road closures where you are. Use this website to find local broadcasters on your route. Avoid using smartphone apps, because they can be distracting while you’re driving.

Rain and roads

2) Check your tyres: Make sure your rubber boots are inflated to the correct pressure, before you leave home. This figure will be listed on the car and in the manual. Also check your tyre’s tread-depth – the deeper it is, the more water it can displace and help prevent skids and aquaplaning (where your car is essentially floating on a film of water – leaving you without any steering control). The minimum legal tread-depth is 2mm, but the AA recommends at least 3mm for winter driving.

3) Charge up and fill up: Don’t leave home without a fully charged phone and plenty of fuel to facilitate unplanned diversions around floods.

4) Inspect your windscreen wipers: Brittle or greasy wiper blades can leave you driving blind in heavy rain. Replacing them is quick and inexpensive, just contact the Crawley Down Group’s service centre now to make sure you’ve always got a clear view of the road ahead. Don’t forget to check your rear wiper at the same time. Also, make sure your air-conditioning is working properly, because wet weather will promote vision-sapping condensation on your windows.

5) Skids: Wet weather makes skidding much more likely, so slowing down is the best way to avoid one, but if it does happen, here’s how to regain control. If you experience a front-wheel skid, keep the wheels in the direction of the skid, while a rear-wheel skid requires you to steer into it – i.e if the rear wheels slide out to the right, you’ll also need to steer to the right. If possible, remove your feet from the pedals and allow engine braking to slow you, but if you need to brake, make it gentle.

6) Aquaplaning: Effectively, this is where your car is floating on a layer of water, leaving you with no steering control. If you find yourself heading for a large area of standing water, you should prepare to aquaplane. Do not slam on your brakes – ease off the accelerator and de-clutch the car if it’s a manual or gently feather the throttle for automatics. Keep the car as straight as possible as your enter the water – your tyres will need to be straight when they reach the other side and regain grip. Aquaplaning is caused by going too fast for the road conditions, so reducing your speed is the best way to prevent it occurring.

7) Turn on your headlights: This will help other motorists see you through the wall of spray that heavy rain creates. However, this does not mean illuminate your foglights – they will blind drivers and mask your brake lights. These are for periods of dense fog – the clue’s in the name.

8) Stopping distances: These increase dramatically in heavy rain, so make sure you’re aware of this while driving. See how distances increase by trying the Royal Society of Preventing Accidents’ wet weather stopping distance simulator.

9) Drop back: Always increase the distance to the car in front during rainy conditions, but especially so when it’s heavy and lying on the road surface. Keep at least five car-lengths back from the vehicle you’re following.

10) Look out for large or fast-moving vehicles: These can create large and blinding showers of spray as they pass you. Always be prepared to slow down or stop.

Driving through a flood

If you’re driving in extreme wet weather, make sure you travel at an appropriate speed – and that you’re able to stop quickly if you come across a flood. If this happens, park in a safe position and consider if you can turn around and avoid it. When this isn’t possible, make sure the water is no more than six inches deep of standing water, or four inches if it’s flowing. Don’t try wading through it to find out, watch as passing trucks or 4x4s negotiate it – looking for invisible dips in the road where the water could be even deeper.

Don’t attempt to drive over flooded bridges, the flowing water can easily float your vehicle and wash it into the river or stream – causing risk to life.

If you decide to proceed, stay in the middle of the road, where the camber will ensure the water is at its shallowest. Only do this if you have clear forward vision to spot oncoming cars. Keep your speed to a crawl, in a low gear with high revs – slipping the clutch will help keep the rpm high, but the speed low. This should stop the engine stalling – and prevent water being pushed into the engine’s air intake.

Driving in floods and heavy rain

Enter the water at 1-2mph, then speed up to no more than 3-4mph once in. Look out for pedestrians and other traffic while driving through the flooded section of road. Drive too fast and your tyres can lose contact with the road – this is known as aquaplaning. If this happens, hold the steering wheel straight and lift off the accelerator until your tyres regain grip.

Once out, make sure you gently test your brakes as soon as possible – stopping can be severely impaired while they’re wet.

Driving across a flooded Ford

A ford is where a road crosses a river or stream – and should not be underestimated in times of heavy rainfall or flooding. There are more than 2000 fords in the UK, but you shouldn’t assume the saying ‘safety in numbers’ applies.

Flooding and heavy rain can cause normally docile fords to become raging rapids. Don’t blindly follow your sat-nav if it directs you through one – the device has little road sense in times of adverse weather. You might be able to see the road emerge on the far side, but you have no idea how deep the ford is – or what else lies beneath the dark water.

First thing to do is look for a depth gauge – most fords have them – which will reveal how deep the water is. A visual inspection will show how fast the flow rate is. Only a few of the UK’s fords have warning gates or lights, so don’t assume it’s safe to cross just because there are no warnings or closures in place.

If you’re at all concerned, turn around and take another route. People have died while attempting to cross flooded fords, so a 20-minute detour is a small price to pay for you and your passengers’ safety.

However, if you decide to proceed, here are our tips for crossing fords in times of heavy rain…

1) Depth: Make sure the water is no deeper than 20cm if it’s fast flowing… just one foot of rapid water is enough to lift the average family car, while 60cm of standing water will do the same.

2) Slowly: Remain in a low gear and keep the engine revs high. Proceed at no more than 1-2mph and.

3) Be prepared: Always be prepared to stop and reverse out if the water deepens unexpectedly – don’t push on regardless.

4) Engine: Don’t speed up once in the water – this could cause water to be sucked into your engine and destroy it.

5) Stay safe: If you breakdown in mid-ford, gauge the depth and flow of water before leaving your vehicle. Just 15cm (six inches) of fast-flowing water can knock you off your feet – and much less for a child or elderly passenger.

Fords can be dangerous even when there’s a low risk of flooding, so check out wetroads.co.uk for advice on any crossings you may need to use.

How to get out of a sinking car

Here’s the AA’s advice for how to get out of a sinking car.

If you breakdown in a flood

In the event of a breakdown in flood water, don’t prop open your bonnet; this will make things worse. If the water isn’t too deep or fast-flowing, get out of your car, lock it and head to a safe location away from the flood and highway until assistance arrives.

If you’re stuck in fast-flowing water, call the emergency services immediately on 999. However, if it’s safe to leave the car, use a warning triangle to alert other drivers.

Avoid contact with the water if possible, it could be contaminated with sewage and fuel.

Wet weather Kit

  • Stay safe in wet weather by making sure you don’t leave home without this kit in your car
  • Mobile phone
  • In-car mobile phone charger
  • Warning triangle
  • Torch/flashlight
  • Light waterproof jacket
  • High visibility vest
  • Foil blanket
  • Spare clothing
  • Snacks
  • Fresh water
  • Wellies

Flood facts

Using common sense is another great way to help motorists stay safe while driving in wet weather and floods. A 2013 survey by the AA and Environment Agency suggests this isn’t always the case, though. Here’s what the research revealed…

More than 50% of UK drivers were happy to endanger themselves and their vehicles by  driving through floods.

The survey of 21,165 AA members also found that 27% of motorists would drive through flowing flood water deeper than 30cm – the depth at which moving water can lift a car.

The AA says that a third of flood-related deaths involve vehicles, because drivers don’t take the risk of flooding seriously.

The motoring organisation also revealed it rescued almost 9000 vehicles that were stuck in floods during 2013 – with the insurance bill totalling more than £34 million.

And finally…

As well as keeping yourself safe, make sure you do the same for other vulnerable road users, such as cyclists and pedestrians. Always slow down and give them a wide berth while passing.

It’s also worth remembering that splashing pedestrians is illegal and can result in prosecution.

Stay safe and dry on the roads.

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