March 15, 1997 It is with mixed feelings of humor and dismay that persons in the field of traffic safety read frequent headlines in the newspapers--even the largest dailies--blaming the weather for automobile accidents. Even some police departments (who should know better), according to accident stories in the newspapers, fall into the trap and take the easy way out of blaming bad weather for accidents. "Two Killed in Fog-Produced Crash", reads one headline. "Five Accidents Caused By Storm", we see bannered across the front page of one of our metropolitan dailies. Persons in the field of Traffic Safety have long known that no inanimate object, an object not in control of a motor vehicle, ever caused a vehicular accident. In every case, it was the failure of the driver (chauffeur) of that vehicle to adjust his driving to allow for or cope with the added hazards imposed by weather be it fog, ice, sleet, snow, rain or glaring sun --- which caused the accident. And for every one driver who had an accident under any adverse weather condition, there are hundreds, yes, thousands, of drivers driving under those same conditions and at the same time, on the same roads, who avoided accidents by adjusting their driving techniques to meet and beat the challenge imposed by bad weather. This attitude, in respect to bad weather causing accidents, is reflected in the investigation reports submitted by investigating officers of this department it is incorrect to give "Bad Weather" as the cause of any vehicular accident. The above, at first glance, appears to be a hard pill to swallow. It is especially hard to swallow for those of us who have had an accident during adverse weather conditions and rather than admit to a lack of perception, on our part, in recognizing the hazard of bad weather have been quick to blame such accident on the weather. Let us first of all give you important facts regarding weather that may be unknown to some of our officers and chauffeurs: 1. The early part of a rainfall is most hazardous for drivers. Accumulated oil and dirt on the roadway with the first few drops of rain is more skid-provoking than packed snow or ice. 2. Everyone has always known that driving in cloudbursts is dangerous, but until recently no one knew just how dangerous. National Aeronautics and Space Administration engineers have found that in heavy rain your tires actually lose contact with the road. With a halfinch of rain, you begin to lose contact at 30 mph; at 60 mph you're running entirely on water like a boat. 1
March 15, 1997 3. The Dunlop Tire Company in England has been conducting research in this area for a year and their findings brought out the following facts: "At 40 mph on a wet road, water starts to build up beneath a wheel like a ship's bow wave, reducing the contact area. As speed rises, the water moves in until, at 80 mph, the contact of the tires is a few square inches. Before the tread can grip the surface of even a moderately wet road, it has to disperse between 8 and 9 pints of water a second. At high speeds, the area of tread on the road has about 1/150th of a second in which to do it. Pressure forces the wedge beneath the front of the remaining contact area. Eventually it spreads to the rear and none of the tread touches the road and you start skimming like a surfboard. A well-worn tread would, of course, start you aquaplaning sooner." 4. In some recent tests by the National Aeronautics and Space Administration it was found that, in a 60 mile speed zone, an automobile traveling at 52 miles per hour actually "hydroplaned" on wet pavement surfaces. The tires were riding on the water out of contact with the pavement with loss of steering and brake control. 5. Here's how one company safety department used such information to alert their drivers to the hazards of high speed driving on wet pavements. The following is taken from a Pacific Motor Trucking Company Safety Department release: For years safety people have been telling drivers SLOW DOWN WHEN THE WEATHER IS BAD! We knew and still do that the reason was the lack of control over a vehicle on wet road surface --- but, we didn't know why! WE DO NOW! The answer came out of the space age of the solving of a tough scientific problem related to missiles and their need to know where they are in relation to the earth. In other words, a matter totally unrelated to our earthbound problem of safe vehicle operation on wet roads. By application of the principles discovered they found a car's wheels hydroplane on wet surfaces. That is, at around 50 mph they found the tire surfaces actually leave the road if there is as much as 1/16 of an inch of moisture on the road surface. The tire pressure had a part in the study and it appears the lower the tire pressure, and the faster the speed, the farther off the road surface does the vehicle `hydroplane'. They prove it with high speed photo studies too. So it's no wonder you can't steer or fully control a vehicle at normal speeds in wet weather --- you see, the doggone wheels aren't on the ground. Now you know too --- so heed the advice! SLOW DOWN IN WET WEATHER! 2
The above five pieces of information are important to our officers and chauffeurs for two reasons: 1. Fire apparatus cannot be as easily controlled in wet weather as it can in dry, and 2. Other drivers cannot control their vehicles in wet weather as they can in dry. Now with a little thought we can see the validity of the statement BAD WEATHER DOESN'T CAUSE ACCIDENTS and with the adoption of the proper driving techniques to compensate for such weather conditions we can largely overcome the problems caused by the weather. Some officers feel it unnecessary to remind their chauffeurs of the hazardous conditions existing, due to the weather, assuming that the conditions are obvious and the chauffeur will automatically recognize the situation. This approach fails to consider among other things, the fact that the chauffeur's idea of hazardous conditions and that of the officer may be far apart. Since the AUTHORITY AND RESPONSIBILITY for the safe response of the apparatus rests with the officer on duty, it behooves him to make certain that his chauffeur is fully aware of hazardous driving conditions brought on by the weather when in the opinion of the officer such conditions exist. The department feels that adverse weather conditions present enough of a problem and hazard to the uniformed force so that information on such conditions are broadcast over our department radio network, with the reminder to take all necessary precautions. The receipt of these messages and recording of same do not constitute the taking of the necessary precautions. The thought and the action that these messages generate while the apparatus is on the road, make for the necessary precautions. The receipt of these messages, or at other times when the officer feels it necessary, it would be proper for such officer to discuss with his chauffeur and entire company the following driving problems caused by adverse weather: 1. Poor visibility. 2. Slippery road surfaces. (See REFERENCE # 1) 3. Snow and/or ice ruts. 4. Failure of most other drivers to properly compensate for weather conditions. 5. The realization that once the precipitation that causes the condition has stopped, certain street surface conditions such as wet and slippery, snow, ice and ruts may be with us for some time and require much the same precautions as during the storm, when the adverse weather was obvious. 3
By adoption of the following, any unit can nullify these problems to a degree, and assure a safe response. 1. The necessity for the chauffeur to adjust his driving habits to compensate for the problems caused by the weather and the need for the officer to insure that this is done. a. Speed to meet conditions. b. Be alert to perceive hazards as soon as possible. c. Properly evaluate hazard and take necessary evasive action. d. DRIVE DEFENSIVELY. 2. Anticipate conditions that will be met at various locations in district and pre-plan necessary driving action to overcome these conditions as much as possible. 3. Consider the possibility of selecting alternate routes that provide safer driving conditions. In conclusion, your failure to perceive and properly evaluate the hazard caused by the adverse weather and to take the proper evasive action in your driving causes the vehicular accident and not the weather. BAD WEATHER IS A CHALLENGE TO A PERSON'S DRIVING ABILITY --- NOT THE REASON FOR AN ACCIDENT. 4
REFERENCE # 1 (FORMERLY SAFETY TIP # 54) FRONT WHEEL LIMITING VALVE A two-way valve which reduces air pressure to front wheel brakes when placed in the Slippery Road position. When roads are wet or slippery and valve is properly engaged, ladder trucks and pumpers can be braked with reduced possibility of jackknife or rear end skid. When road conditions are favorable, return the valve to the Dry Road position to avoid excessive wear on rear brakes. 5