The wail of sirens, flashing of lights, and appearance of a red fire truck provoke interest, excitement, and a sense of danger. There is danger not only in fire fighting but also in responding to the fire scene. The National Fire Protection Association reports that fire apparatus accidents are the second-largest cause of firefighter deaths (Washburn, LeBlanc, & Fahy, 1995).
Driver safety training is a common component of fire department injury reduction programs and has been for several decades. Yet fire apparatus accidents continue to occur. In this article we will explore the possible contribution of fire truck color to these accidents and make recommendations for improved visibility.
Color and Safety
A review of human visual color functions sets the stage for questioning the [choice of red for] fire vehicles. In the mid- 1800s, Helmholtz wrote about the human eye as red-weak. When human eyes are adapted to daylight (photopia), the color red is seen with much greater difficulty that are most other colors. At night, when eyes are dark adapted (scotopia), they are practically red-blind (Hart, 1992; Southhall, 1961). Traquair (1949) found that certain colors can be seen farther into the visual periphery than others, thus offering earlier detection. Red has a narrow lateral range, whereas yellow's range is much wider (Traquair, 1949). Allen (1970) stated that color-defective individuals struggle with the color red but can see yellow much more readily. In fact, 8% of the male population is red/green defective; of this group, 25% are red-blind (Allen, 1970).
In an attempt to make fire apparatus more visible, fire officials often paint the vehicles in two tones. The most popular combination is red and white - the logic being that red is used for tradition and white for visibility. Unfortunately, red/white two-tone lists tenth (near the bottom) on the visibility list for paired colors (Nathan, 1969). Sleight, in his research for the Highway Research Board, pointed out that two-tone colors may actually camouflage vehicles against the background (Leonard & Sleight, 1967). These findings lead us to ask, Does the choice of fire vehicle affect accident probability? What color is the safest?
We recently demonstrated that the probability that red and red/white fire apparatus will be involved in an accident is greater than that of lime-yellow/white fire apparatus. We focused our analysis on a single city - Dallas, Texas - to reduce the effect of variables such as training, law enforcement, traffic densities, weather conditions, apparatus operation, vehicle inspection and maintenance, and length of runs. We chose Dallas because both lime-yellow/white and red and red/white fire apparatus were simultaneously in service and geographically uniformly distributed during the period 1984 through 1988.
Which Color Is Safest?
Recently, DuPont researcher Dr. David H. Alman measured chroma and reflectance of DuPont paints typically used in the transportation industry; his studies were conducted under controlled lighting representing daytime and nighttime illumination. Lime-yellow (reflectance peaking near 550 nm wavelength) was shown to have the "best fit" for the sensitivity curve of human photopic (daylight) vision. Thus, the daytime and nighttime eye response to lime-yellow is strong, enabling more rapid reaction. Because lime-yellow is also an intense color, it is easily distinguished from rural and urban backgrounds (Allen, 1970). These factors, combined with reflectance approaching white, make lime-yellow a prime candidate for the safest color for fire apparatus.
Where Do We Go?
Color choice within a given finish type is not cost driven, so vehicle safety can be enhanced without added cost. From a human factors perspective, there are two broad areas of professional application: First, the fire service must be convinced to move from the traditional but unsafe paradigm of red apparatus to safer lime-yellow colored vehicles. Second, the manufacturers and purchasers of motor vehicles must be educated as to the potential of color to reduce accident rates and accident severity.
Excerpts from "Fire Truck Visibility" by Stephen S. Solomon & James G. King, in ERGONOMICS IN DESIGN, Volume 5, Number 2, April 1997. Copyright 1997 by Human Factors and Ergonomics Society, P.O. Box 1369, Santa Monica, CA 90406-1369 USA; 310/394-1811, fax 310/394-2410, hfes@compuserve.com. To obtain a copy of the entire article, which includes full references, contact Lois Smith at the address given above.