If used properly, cruise control can provide benefits that will help you operate more efficiently and profitably. You can reduce fuel consumption, reduce maintenance costs, and comply with speed limits – and realize significant savings along the way. However, there are two traction-related hazards of driving in the rain. First, during the initial minutes after it begins raining, the oil, grease, and dirt on the road can create slippery conditions, so reducing speed during this time is important. Drivers who aren’t paying attention will forget that cruise control is maintaining a constant speed, and as a result, speed will not be reduced as needed, increasing your chances of losing control and getting into a crash.
Secondly, especially after heavy rain, a film of water may form between the tires and the roadway. When this happens, you will actually ride on top of this film, losing all traction, and you may be unable to steer, brake, or accelerate. This dangerous condition is called “hydroplaning,” and it can happen at speeds as low as 35 mph. The higher your speed, the greater the chance of hydroplaning.
Cruise control presents a problem during these conditions because it will want to keep your vehicle going at a constant speed. When you begin to hydroplane, the system may sense a loss of traction and will respond by increasing speed, and this increases your chances of losing control and getting into a crash.
Some drivers think that braking will help if this occurs, because braking disengages the cruise control. However, braking is the last thing you should do if you begin hydroplaning, because it may cause you to lose control. Your first response should be to take the foot off the accelerator and then brake once you sense traction has been restored. For these reasons, the safest thing to do when it begins raining is to turn off the cruise control and reduce speed.
Finally, operators of CMV’s (Commercial Motor Vehicles) should remember that FMCSR §392.14 states "extreme caution in the operation of a CMV shall be exercised when hazardous conditions… adversely affect visibility or traction.” In any case, drivers of all types of vehicles must be sure to fully comprehend how to use cruise control on the specific vehicle they operate, how to disengage it, the hazards of misuse, and its limitations.
Michael Nischan, CDS
Loss Control & Safety Consultant
NATMI Instructor
michael.nischan@mccart.com
678.475.5720 office
678.938.2012 cellular
678.475.3852 fax