Safety

The dangers of driving in flood waters

car driving through flooded waters

Jessica Taylor Yates

Posted October 25, 2022

The SES rescue more than 100 drivers who wrongly thought it was safe to drive in floodwater every year. Find out why it's so dangerous to drive through water and should be avoided at all costs. 

With the La Niña and negative Indian Ocean Dipole weather events forecast to continue to burden Victoria’s roads with heavy rain and flooding for the remainder of 2022 and start of 2023, it’s more important than ever to understand the danger of flood waters on the road.

According to the National Road Safety Partnership Program (NRSPP), driving in flood waters is the second deadliest natural hazard Australians face on the road.

RACV Driving School Senior Instructor Silvia Morris warns that no matter if you drive a small mini coupe or a large SUV, driving through flood waters “is a dangerous and life-threatening decision”.

Here’s what to do if you find yourself in a wet or flood prone area, and how to best prepare before finding yourself in unsafe territory.

Stay up-to-date via the VicEmergency website or app and check VicTraffic for road closures and hazards during storms. Phone VICSES on 132 500 for assistance or Triple 000 in an emergency.

Why is it unsafe to drive through flood waters?

The Victorian State Emergency Service (SES) has released a campaign called ’15 to float’ to educate motorists about the very small amount of flood water that is needed to make a car float.

A standard one-tonne small hatch or coupe can float in as little as 15 centimetres of water, while a large two-and-a-half-tonne 4WD can float in as little as 45 centimetres. For context: that’s below knee-height for an adult.

The SES has now responded to more than 100 requests for assistance related to vehicles that have become stranded in water over the past nine months.

While moving flood waters can cause your vehicle to lose traction and wash away without much difficulty, what belies the surface of the water is of equal concern. “You may not be able to see other hazards in large bodies of water, such as large potholes, or debris,” says Morris.

From a distance, flood waters may not appear to be too high or dangerous, but are often deeper and faster flowing than they appear. With severe flooding impacting large areas, harmful chemicals can also enter the water, along with debris and even animals that can cause severe illness.

Even if you are able to drive through a flooded road, you’re still not safe yet. Having so much moisture on your brake pads can seriously impair your ability to brake suddenly.

If you find your car has been sitting in deep water, do not attempt to drive it, as the car’s electrics may have also been compromised impacting critical safety equipment.

It is best to contact your insurer for assistance to navigate the next steps. 

What is aquaplaning? How does it happen?

Also referred to as hydroplaning, aquaplaning is when a layer of water on the road builds up between the surface of road and the vehicle’s tyres, causing the tyres to lose grip on the road. Aquaplaning then causes the driver to lose control of the vehicle, including steering, braking, and acceleration.

Aquaplaning, of course, occurs on wet roads, but the risks are exacerbated with tyres that have low tread and speed.

To avoid aquaplaning, keep up to date with your tyre safety, and ensure that they are up to the legal standard for tyre tread depth and pressure. 

 

driving on a wet road

It's imoprtant to keep a safe breaking distance when driving on wet roads. Image: Matt Harvey. 

Why do people risk driving in flood waters?

While evacuating and attending a rescue are common reasons why motorists find themselves in flood waters, social pressure is a major contributing factor as well.

When deciding whether to drive on a flooded road or not, seeing others do it successfully can act as a social pressure and motivate a driver to follow them.

“[It’s best to] set a good example, as people are more likely to drive through flood waters if they see others doing it, then do not encourage this behaviour by doing it yourself," says Morris.

"By choosing not to drive through it, you may not only save yourself, but you can lead by example and help keep others safe too.” 

What happens if your car is stuck in flood waters? 

If you find yourself coming up to a flooded area, even if you are experienced in driving in inclement weather, Morris advises to steer clear. “If in doubt, stay out,” she says.

“In extreme weather conditions, choose to postpone your journey. It’s just not worth the risk to put yourselves and others in danger”.

If you find yourself driving in heavy rain with wet roads, it’s best practise to:

  • Turn on headlights when visibility has been reduced
  • Reduce speed
  • Keep an eye out for changing conditions, such as flash flooding
  • Stop before a road that is flooded or covered in a large body of water

If other vehicles are on the road, as a guide, a driver should keep at least four to five seconds distance from the car in front, in order to give your car time to break in time safely.

If you unexpectedly find yourself on the road during an extreme event, the safest thing to do is to drive somewhere safe, including higher ground, and wait for conditions to improve.

Stay calm, dial 000, and signal to others for help if needed. Alternatively, contact the State Emergency Service (SES) on 132 500.

 

driving in wet weather

A car can float in as little as 15 centimetres of water.. Image: Getty. 

Flood prevention measures

If you are in an area that is at risk of flood, ensure you have adequately prepared your home and have evacuated if instructed to do so.

If you are in a high-risk area, ensure you have taken adequate steps to prepare an emergency flood plan, having a prepared emergency kit with your important documents, and monitor severe weather events though VicEmergency.

Plan your route before driving with arevo, which provides up-to-date information on road closures and flood warnings. 

 

Be prepared no matter the weather.
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The information provided is general advice only. Before making any decisions please consider your own circumstances and the Product Disclosure Statement and Target Market Determinations. For copies, visit racv.com.au. As distributor, RACV Insurance Services Pty Ltd AFS Licence No. 230039 receives commission for each policy sold or renewed. Product(s) issued by Insurance Manufacturers of Australia ABN 93 004 208 084 AFS Licence No. 227678.