This document provides an overview of hydroplaning, including contributing factors, how to avoid it, and what to do if it occurs. Hydroplaning is when a layer of water builds up between a vehicle's tires and the road surface, causing loss of traction and control. It can happen at speeds as low as 30 mph and is a major cause of weather-related crashes. To avoid hydroplaning, drivers should slow down in wet conditions, avoid driving through standing water, and ensure proper tire inflation and tread depth. If hydroplaning does occur, the driver should take their foot off the accelerator and steer in the direction of any slide until traction is regained.
3. 1. IntroductionApril showersbringshydroplaning
* 75% of weather-related
crashes occur on wet
pavement*
* 47% involve active rainfall*
*15% involve snow or sleet *
* 13% involve ice/freezing
rain*
*11% a mix of snow/slush
covered pavement*
• Weather-related crashes
occur in adverse weather
i.e.;
⁄ Rain
⁄ Sleet
⁄ Snow
⁄ Fog
• or on slick pavement i.e.;
Wet
Snow/slush covered
Icy/frozen/untreated pavement
*Nearly 7,400 people are
killed and over 673,000 are
injured in weather-related
crashes every year.*
*Federal Highway Administration (FHWA) stats*
4. • Hydroplaning is when a layer of water builds up
between the vehicle’s tires and the road surface
causing the loss of traction and possible control.
• Tires enable vehicles to start, stop, change speed
and turn, but only if they can “grip” the road.
• Car and truck tires are designed to push away rain,
snow, and mud, but sometimes a tire may come
upon more water than it can displace.
5. When a tire cannot move water aside the water
pressure in front of the wheel forces a wedge of water
under the leading edge of the tire. This causes the tire
to lift off the surface of the road. The tire then “skates”
on a sheet of water with little or no direct contact with
the road. Without proper contact the ability to steer,
brake, or accelerate is compromised.
When a vehicle’s tire actually lifts up off the road, it
loses traction becomes uncontrollable.
When multiple tires hydroplane this can cause the
vehicle to lose directional control until it either crashes
or slows down enough for one or more tires to contact
the road again and regain traction (friction).
When multiple tires hydroplane this can cause the
vehicle to lose directional control until it either crashes
or slows down enough for one or more tires to contact
the road again and regain traction (friction).
Direction of travel
When a tire cannot move water aside the water
pressure in front of the wheel forces a wedge of water
under the leading edge of the tire. This causes the tire
to lift off the surface of the road. The tire then “skates”
on a sheet of water with little or no direct contact with
the road. Without proper contact the ability to steer,
brake, or accelerate is compromised.
When a vehicle’s tire actually lifts up off the road, it
loses traction becomes uncontrollable.
Surface of road
6. 2. Contributing Factors …
Inadequate tread depth – the grooves on tires channel
water, snow, and slush away so the treads can “grip” the
road.
If tire grooves are too shallow or non-existent the tire can
spin without effectively gripping the road.
Quarter test: If the top of Washington’s head is at the
top of the tread, the tread depth is OK (4/32”) but
getting close to inadequate.
Penny test: If the top of Lincoln’s head is at the top of the
tread, the tread depth is less than 2/32”. It is inadequate
and the tire needs to be replaced.
Quarter test: If the top of Washington’s head is at
the top of the tread, the tread depth is OK (4/32”)
but getting close to inadequate.
Penny test: If the top of Lincoln’s head is at the top
of the tread, the tread depth is less than 2/32”. It is
inadequate and the tire needs to be replaced.
7. Speed – as a vehicle’s velocity increases, tires can ride up on top of
snow, ice, and water. As the wheels turn faster, they lose the ability to
channel away water, snow, and slush. Hydroplaning can happen at
speeds as low as 30 mph.
Slow down if driving through standing water cannot be avoided.
Water depth – caused by heavy downpours or poor drainage
contributes to the possibility of hydroplaning. Loss of traction can
occur on any wet road, but all drivers must be extra careful when
encountering large pools/sheets of standing water.
8. Improperly inflated tires
Improperly inflated tires – especially under inflated –
Under inflated tires do not effectively push away water
Over inflated tires do not provide maximum traction or “grip.”
9. 3. How to Avoid Hydroplaning
SLOW DOWN
• Slow down before driving
across large puddles.
• Slow down during heavy
downpours –water may not
be able to run off highway
surfaces quickly enough.
• Take your foot off the
accelerator and allow the
vehicle to slow down
gradually. Immediately
stepping on the brakes can
cause the wheels to slide.
Proper maintenance &
driving behaviors
• Before you encounter hydroplaning
conditions – make sure the vehicle is in top
condition: check tire pressure; tread depth
and condition; use the right tire design for
the vehicle and type of driving.
• In extreme weather eliminate distractions
while driving (concentrate on the feel of the
vehicle and its sounds).
• Follow the directions offered by the vehicle
manufacturer for braking with Antilock
Brakes (ABS) if the vehicle is equipped with
this feature.
• Do not use “cruise control” when conditions
for hydroplaning are present. A vehicle’s
tires can speed up when they lose contact
with the surface of the road and ride on top
of the water.
• Do not tailgate – but follow in the tracks of
a preceding vehicle.
10. 4. How to know when a vehicle
is hydroplaning.
• If a vehicle’s drive wheels are hydroplaning, engine RPMs may suddenly
increase as the wheels spin on top of the water.
• While driving straight a vehicle may vibrate or “wiggle” in the steering
mechanism, or feel like the steering is “loose” or “soft.”
• Not seeing tire tracks (in the mirror) immediately behind the vehicle may be
due to the tires not “cutting through” the water effectively.
• Any sideways motion (skidding, fishtailing, etc.) while navigating curves is a
strong indicator of hydroplaning.
11. For Example: if the rear end of
the vehicle slides to the RIGHT,
steer quickly and smoothly to the
RIGHT. This is known as “turning
into the slide.”
• If a vehicle is sliding, skidding and/or fishtailing,
taking your foot off the accelerator – do not hit
the brakes. The sudden application of brakes can
lock the wheels, contribute to the slide, and loss of
control. As the tires slow down, traction should
return.
• Do not make sudden moves with the steering
wheel (if already in control) – do not try to swerve
to see if you are hydroplaning – it might not end
well.
• If in a slide, allow the vehicle to slow down to get
traction and make gradual moves instead of sharp,
sudden movements.
How to Recover
from Hydroplaning
12. Summary:
Avoid
Hydroplaning• Slow down during extreme
weather and slippery roads
• Avoid driving through
standing water
• Stay calm if the vehicle begins
to hydroplane
• Reduce speed to recover
traction and control
• Give extra space between
vehicles
• Make sure tires are properly
inflated, have adequate tread
depths, and are the right type
for the vehicle
13. HydroplaningPrint and post: SafetyFirst Systems, LLC MTMTT- April 2016
• Slow down before driving across
large puddles.
• Slow down during heavy
downpours –water may not run
off the highway surfaces quickly
enough.
• Take your foot off the
accelerator and allow the vehicle
to slow down gradually.
– Immediately stepping on the
brake can cause the wheels
to slide*.*Follow the directions offered by the vehicle manufacturer
for braking with Antilock Brakes (ABS) if the vehicle is equipped with this feature
• Check tire pressure, tread depth and condition
• Eliminate distractions
– concentrate on the feel and the sounds of
the vehicle
• Do not use “cruise control” when conditions for
hydroplaning are present.
– A vehicle’s tires can speed up when they
lose contact with the surface of the road
and ride on top of water.
• Do not tailgate – consider following in the
tracks of a preceding vehicle.
• Federal Highway Administration (FHWA) stats:
– 75% of weather-related crashes occur on
wet pavement
– Nearly 7,400 people are killed and over
673,000 are injured in weather-related
crashes every year.
Print and post: SafetyFirst Systems, LLC MTMTT- March 2016 *If the vehicle is equipped with Antilock Brakes (ABS) read and follow
the directions offered by the vehicle manufacturer for this feature.
Slow Down Proper maintenance & driving behaviors
