To avoid accidents during the rainy season, beyond focusing attention and adjusting speed to suit slippery road conditions, it also requires driving skills and vehicle readiness combined.
Many people often ask, "How much should one reduce speed when driving on wet, slippery roads in the rain to stay safe?"
According to general safe driving principles, when heavy rain makes roads wet, speed should be reduced to two-thirds of the normal speed used on dry roads. Slowing down to an appropriate speed helps tires expel water and grip the road surface better, while also giving the driver more reaction time to assess situations, steer away, or respond to emergencies promptly.
Moreover, not driving too fast in rain is crucial to reducing "hydroplaning," a condition where a layer of water separates the tire from the road, causing loss of grip. At high speed, the vehicle will skid immediately, and the driver loses control of steering and braking, which is a leading cause of severe accidents repeatedly occurring in the rainy season.
If you are driving well but suddenly hit a water puddle causing "hydroplaning" or the vehicle starts to skid, the first thing to do is remain calm and not panic. Although this sounds simple, it's difficult because sudden skids often cause drivers to panic and make mistakes.
The most important rule is "never slam on the brakes." Hard braking causes the wheels to lock and stop spinning immediately, leading to a severe loss of traction, making the car spin uncontrollably in the middle of the road and nearly impossible to recover control.
What to do when hydroplaning begins:
Immediately lift your foot off the accelerator to allow the speed to decrease smoothly.
Hold the steering wheel firmly and steadily, keeping the direction straight.
Once speed decreases and tires regain grip on the road, gently tap the brakes to slow down safely.
The best prevention is to reduce speed as soon as rain starts to avoid hydroplaning altogether. For vehicles with good tire condition and deep tread, the safest speed in heavy rain with standing water on roads should not exceed 80 kilometers per hour.
As speed decreases and water is expelled beneath the tires, they regain road contact, allowing you to control the steering normally again.
According to driving physics, at around 45 kilometers per hour, most of the tire surface remains in contact with the road. But increasing speed to 90 kilometers per hour or more causes water pressure to lift the car, breaking tire contact and causing hydroplaning when passing puddles.
A clear example is the case of the rear-wheel-drive BMW Z4 sports car involved in a tragic accident. Traveling over 140 kilometers per hour in rain, hitting a puddle forced water under the front wheels, causing the wheels to lose traction instantly. This led to rapid loss of control beyond any steering skill to recover.
Additionally, for heavy-load vehicles like pickup trucks, it is important to evenly distribute weight before traveling in the rainy season, alongside checking tire tread depth, brake functionality, windshield wipers, and all lighting systems for proper operation.
Additional guidelines during heavy rain crises:
If caught in a severe storm with poor visibility, do not stop on the roadside due to high risk of rear-end collisions. Instead, use turn signals to pull into a gas station or find a safe parking area well away from the shoulder.
Do not turn on hazard lights while driving through rain because it confuses other drivers, especially at intersections, possibly causing them to think your vehicle is stopped or turning, which can lead to secondary accidents.
At the first sign of rain, immediately increase the distance from the car ahead to twice the normal gap, as wet roads significantly extend braking distances. Slowing down and maintaining safe distance not only prevents rear-end collisions from skidding but also provides time and space to brake or swerve safely in emergencies.
Another overlooked risk is "windshield tinting." Dark or overly opaque tint severely reduces visibility in rain, especially at dusk when natural light fades and rain impairs vision, possibly obscuring obstacles ahead.
For maximum safety, windshield tint should not be too dark, as even premium-grade tints cannot provide clear visibility during rainy conditions comparable to normal weather.
Reminders
Prepare for rainy driving by checking equipment such as tires, windshield wipers, brakes, lighting, mobile phone battery, and emergency contact numbers.
Do not reduce tire pressure in an attempt to increase grip, as this does not improve road holding but causes rapid tire wear and heat buildup, risking blowouts.
Use appropriate speed and heightened caution. Remember that excessive speed can cause accidents via increased braking distance and loss of control during braking.
Maintain greater distance from the vehicle ahead, calculating stopping distance carefully, considering water and slippery conditions as variables. Always prioritize safety.
Avoid overtaking unless necessary, and if not overtaking, allow faster vehicles to pass.
Skilled and proper brake use according to the situation helps keep you safe from accidents in the rain.
Be cautious of water splashing onto pedestrians; understand and respect others sharing the road with you.