Danger: High Winds
On Wednesday, Nov. 11, 2015, at least three tractor-trailers rolled over in Iowa. Wind gusts are suspected to have contributed to the crashes. This is a concern because truck rollovers are the number one cause of fatalities for commercial drivers, especially if the driver is not wearing a safety belt.
Facts on the Wind
Weather reports usually tell us two or three characteristics of wind: direction and speed and sometimes the speed of any gusts. A straight tailwind is great. Pushing air is one of the biggest reasons trucks do not get great fuel economy. A headwind always takes extra fuel to overcome air resistance (drag).
There are several ways wind is defined. Basic wind speed is a measurement of average wind over a period of ten minutes. (ISO 4354) As it is an average, that means actual wind speeds can be higher. Wind speed fastest mile measures the speed of the wind as it moves one mile and are typically higher than wind measured over a period of ten minutes.
Wind gust speed, a sudden increase or decrease in wind velocity, is determined by a gust factor (about 1.5) applied to the average wind speed. Surface winds are considered dynamic and are constantly changing.
Trucks pulling dry vans or reefers are most at risk for high-wind hazards. A trailer does not have to be moving to be damaged. A strong enough wind gust can break a trailer sitting in a parking lot.
The most critical wind direction is wind blowing perpendicular to the direction of travel or a side-gust wind. Drivers may first notice a rocking sensation from the wind gust, as if riding in a boat.
Vehicle speed has an effect on whether or not a loss of control will occur at a given wind gust speed.
Loss (or gain) of vehicle control may be induced by driver inputs as steering, accelerating or braking.
Here the driver was able to make an unbelievable recovery by pulling off the road into a Kansas field.
Wind gusts can cause the trailer to swing out in low traction conditions as standing water, snow or ice.
Leave plenty of following distance between other commercial motor vehicles. A number of states enforce a 500 foot following distance rule for trucks. Drivers may be given tickets for following too closely on bridges also.
One company had three of their trucks traveling together, blown off the road in strong winds.
Gusts approached 50+ MPH, lifting this trailer’s wheels off of the road.
Tips for Driving in Windy Conditions
• Check the weather as part of the trip-planning routine.
• If the weather turns bad, keep a “weather radio” handy and tune in to the the National Oceanic and Atmospheric Administration (NOAA) Weather Radio All Hazards (NWR) system. NWR is a nationwide network of radio stations broadcasting continuous around-the-clock weather information.
• Keep in mind that actual wind speeds and gusts may be higher than broadcast weather reports. Wind can be unpredictable.
• Reduce speed in windy conditions.
• Reduce speed in inclement weather: rain, snow, or when driving on icy roads.
• Reduce speed in low traction conditions as rain, snow, or ice.
• Don’t bunch up several trucks in a road convoy.
• Don’t drive in risky, high wind conditions.
• Insure any freight is properly distributed for a low Center of Gravity.
Thank you for reading this.