Accidents caused by cruise control and aquaplaning
Even some authorities have been fooled by false claims about cruise control and how the system can cause accidents on wet roads.
Poorly researched alarmist emails and news reports about the dangers of cruise control have left many motorists confused about the system. I have personally met many drivers who are afraid to use cruise control under any circumstances. Convincing them that using cruise control can actually reduce both fatigue on a long journey, and fuel consumption, is something of an uphill battle.
Cruise control, starting with its most primitive forms, has been around for almost as long as motor vehicles. The modern version, setting the road speed instead of the engine speed has been available on many cars for almost 50 years. In the last ten years even greater advances have been made with the technology.
But rumour persists that cruise control is dangerous. A typical circulating email tells of the car that starts to aquaplane on a wet road while on cruise control.
It was raining, though not excessively, when her car started to hydroplane and literally flew through the air. When she explained to the policeman what had happened, he told her something that every driver should know – NEVER DRIVE IN RAIN WITH YOUR CRUISE CONTROL ON.
He said that under those conditions the car would actually leave the ground and fly, attaining a higher speed than when it was on the road and was probably doing 10 to 15 km/h faster.
Perhaps that policeman missed his calling and should be advising aircraft designers and pilots on how to get the best performance from real flying machines.
Another persistent myth is that sometimes cruise control cannot be switch off. That one is totally without foundation. A quick check of the foot should tell the driver that the foot should be on the brake pedal rather than the accelerator.
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But the truth is that cruise control cannot cause an aquaplaning vehicle to fly or go faster. That proposition defies all the laws of motion, dynamics and aerodynamics. It is just impossible for it to happen while aquaplaning. However, basic cruise control systems do not control speed absolutely and host vehicles will decelerate or accelerate, while climbing or descending hills. It is also important for drivers to remember that cruise control cannot see ahead to corners or backed-up traffic. That is still up to the driver. A sound piece of advice here would be – NEVER DRIVE INTO A CORNER THAT YOU DON’T KNOW WITH YOUR CRUISE CONTROL ENGAGED.
Typically, an experienced driver will disengage the cruise control approaching a corner and engage it again as the vehicles straightens up again. It is not a major operation, and it is safer that way.
On all vehicles, disengaging the cruise control offers a choice. There is an ON/OFF switch, but for most situations that is not the preferred way. The brake pedal, or the clutch pedal on manual transmission vehicles, is usually the preferred means and a light touch of the foot will instantly disengage the system. On most vehicles it is not necessary to push the pedal down far enough to apply the brakes or to disengage the clutch. Just a light touch on the pedal is usually sufficient to put the vehicle into slowing mode. Braking can be applied after that as necessary.
Once safely around the corner the RESUME switch can be clicked and the vehicle will then accelerate again to its pre-set speed. If the ON/OFF switch is used, the driver will then have to select ON and re-set the chosen speed again.
The most modern cruise control systems are highly sophisticated, allowing the driver to select the degree of speed fluctuation for descending steep hills. For example if the driver selects +5 km/h, then the auxiliary braking system will take over at 5 km/h over the pre-set speed to stop the vehicle running away, and this may include changing automatically to lower gears. Automatic gear changes may also be possible while climbing with cruise control. Using cruise control with automatic gear changing guarantees gear changes timed for optimum efficiency, and the cruise control can do that better than the driver and save fuel, and wear and tear.
Finally, a driver who uses cruise control is less likely to inadvertently exceed speed limits and have fines to pay.