Driving in heavy rain and flooding: Checks, tips and advice

Published on 9th February 2016 in Driving tips

Rain Car 600

Motorists are used to a Britain battered by floods and near-total washouts that wreak havoc. The winter of 2013 to 2014 was the wettest for nearly 250 years, and this year might fare no better with torrential rain sweeping in from the Atlantic to cause persistent flooding. But while there are public awareness-raising campaigns in place for people and property protection such as the Environment Agency's #floodaware and the nationwide #FloodFreeHomes, there are few comparable schemes for motorists driving in heavy rain and on flooded roads.

That's why we've put together this series of crucial car checks and driving tips to prepare you for tackling wet roads in monsoon-like downpours. According to a recent report by the Department of Transport, there were 9,802 accidents in 2014 caused by 'slippery roads due to weather' - accounting for eight per cent of all road accidents. Supporting studies by the Royal Society for the Prevention of Accidents (RoSPA) show that most of us have very little experience of driving in extreme conditions - and even those who feel they've mastered the art of rain-related driving are at risk.

No matter how much state-of-the-art technology your car is kitted out with, it's not fully water resistant. Nor will it cope well with higher-than-average rainwater. It takes as little as 60cm of standing water to float a car and around 30cm of fast-flowing water to push an average family-sized car off the road, so you need to get it right. Here's our go-to guide:

Top checks to perform on your car prior to driving in heavy rain and floods

Test your tyres

It's crucial your tyres perform when it comes to straight line braking, cornering, and gripping wet and flooded roads. Prior to driving in rain, inflate all tyres to the correct pressure level and make sure none has cuts, cracks, bulges or punctures. To check that the tread depth meets the legal minimum requirement of 1.6mm across the central 3/4 of the tread, try this simple trick. Park your car on level ground and place a 20p coin flat in one of the grooves of the tread. Repeat on all tyres. If you can see some of the outer edge of the coin, the tread is too low.

Sort wiper blades

When driving in heavy rain, it's vital that both the front and rear wipers are functional - and that the rubber-stripped blades are not torn, split or worn out. As soon as you hear a dragging sound as you watch them struggle to clear the glass, replace the single rubber blades or buy a new clip-in unit. While easy to change, your local IMI-registered technician can troubleshoot any fitting problems. Equally important is screenwash to keep your windscreen clean and clear. Top up the washer bottle with a 50:50 mix of screen wash and water - and check the washer jets work.

Flash your lights

According to the Highway Code's Driving in Adverse Weather Conditions (Rule 227), motorists must use headlights when visibility is seriously reduced - usually when you can't see for more than 100 metres. Before driving in rain, give all interior and exterior car lights a quick once-over, turn on your dipped beams, and check that every single bulb (including the indicators) is fully illuminating. No light should be dirty, obscured or misaligned. If your car has automatic headlights, make sure the sensors activate correctly.

Get brakes checked

Neglecting your braking system can be lethal, especially when facing the challenges of wet and flooded roads. If a problem arises, contact your local IMI-registered technician immediately for rigorous checks - and prompt replacements - of key hydraulic and mechanical components. These include brake discs and drums, brake pipes, the brake servo operation, and more. Also check that your car’s brake fluid levels are correct, referring to the user handbook if need be.

In-car tech checks

Things have changed somewhat since the Marconi eight-valve receiver was fitted into the rear compartment of a Daimler Light 30 in 1922. Nowadays, in-car audio technology is a necessity for all-weather driving. If you don't have a fitted state-of-the-art stereo system, portable battery-operated radio will do the job just as well for weather warnings and local travel updates. Equally important is an in-car mobile phone charger - a lifesaver if you break down.

Top tips and advice on driving safely in heavy rain and flooding situations

Adjust your driving style

Driving in rain is about getting back to basics. Stopping distances double in the wet, so you'll need to keep good distance from the car in front and apply your brakes moderately. When driving through surface water, keep your engine revs high and reduce your speed to no more than five miles-per-hour in order to dodge sprays, splashes and skidding. Remember never to use your fog lights as they will dazzle other road users - stick to headlights only. Should steering become unresponsive, ease off the accelerator and slow down gradually.

Always act with caution

No motorist sets out intending to negotiate his or her way through a flood, but it's sometimes unavoidable. If you are not sure of the water's depth, look for an alternative route. But if you deem the road shallow enough to cross, take extra caution. Watch the cars in front of you to gauge the water level, crawl through the flood in first gear, keep the engine speed high by slipping the clutch, and always test your brakes before pushing on with your journey. Once you're committed to crossing the flood, just keep going. Stopping the car mid-way due to an attack of nerves will worsen the situation and increase your chances of getting stuck - and stranded.

Avoid aquaplaning

Unlike skidding where some traction is preserved, aquaplaning is what happens when the water between your tyres and the road surface cannot be cleared quickly enough. This makes the four tyres lose all traction and your car unresponsive to steering, braking or accelerating as it’s 'lifted' from the road's surface. Terrifying as it sounds, in 99 per cent of cases it only lasts for a second or two. If it happens to you, do not make any speed or directional changes. Hold the steering wheel, ease off the accelerator, and do not use the brake. To avoid aquaplaning, reduce your speed, consider driving in a lower gear, and refrain from driving through standing water.

Do not panic

There is no 'right way' to tackle standing water in very stressful situations, and in many cases, your flood-damaged car will break down. Depending on your whereabouts and the severity of the situation, pull over in a safe place, call the emergency services and/or roadside assistance, and switch on your hazard lights to alert other drivers. Immersion in water can wreak havoc with your car's engine and electrical system, so if your car has stood in water for an hour or more book it for a post-flood inspection with an expert listed on the IMI Professional Register.

Drive only if necessary

Simple as it sounds, avoid non-essential journeys - or postpone them until the heavy rain or flash flooding has subsided. Never take risks, nor defy advice issued by the Met Office's National Severe Weather Warning Service. Accessible via smart phone apps, radio and TV, social media, RSS, email alerts, and its own website, it is committed to flagging up weather conditions that affect safety - and helps the public to make informed decisions about their day-to-day travel.

Get tips and advice direct to your inbox

Share this article

Get tips and advice direct to your inbox

Related Articles

Driving tips
Carwingmirror rain 470x264

9th February 2016 by The IMI

Driving in heavy rain and flooding: Checks, tips and advice

Make sure you are prepared for driving in heavy rain by checking out these handy tips and safety advice.

Read more

Driving tips
IMI BlogPicv0101 470x264

19th January 2016 by The IMI

Driving Safety Infographic: Common causes of road accidents due to vehicle defects

Find out about the common vehicle defects that cause road traffic accidents and how you can avoid them.

Read more

Driving tips
Tyre 470x264

22nd December 2015 by The IMI

Winter Driving Safety Tips: Driving from A to B with no accidents

For more information on preparing your car for the cold this winter, check out our winter driving tips article.

Read more