One of the most underrated safety devices on emergency vehicles may well be a retro-reflective/fluorescent tape. It is always visible, requires no electrical power, adds negligible weight and is highly cost-effective.
The retro-reflective portion works only at night and is energized by oncoming lights from other vehicles. The fluorescent portion works only during daytime (from dawn till dusk) and is activated by the ultraviolet rays from the sun.
While the retro-reflective/fluorescent products are available in many colors, several stand out from the rest. The most visible colors, day and night, are yellow and lime-yellow, with lime-yellow having the safety advantage because of visual impact.
When considering chevron pairs, offering a contrast to lime-yellow is the red stripe. The result is lime-yellow, offset by red, is the most visible and safest of the chevron color choices and offers superior attention-getting responses. This fluorescent lime-yellow and red chevron pattern should be used on all emergency vehicles that use chevrons, regardless of service branch.
Why not white? While white can be measured as reflecting light, it does not have the brightness of lime-yellow or yellow. White does not attract attention. Pairing red and white in a chevron pattern is not as safe as the lime-yellow/red choice.
Around the clock, the fluorescent lime-yellow/red chevron choices are the highest rated. And either day or night, those tape applications that are free of dirt are most effective.
In addition to the selection of color, the patterns selected are of prime importance. The large-area chevron pattern on the rear is the standard but more attention needs to be paid to the overall patterns on the sides of vehicles. While logos are popular, they do not provide enough visual information relating to the outline of the vehicle.
Especially at night, it is important to use enough retro-reflective material to offer a general outline of the sides of the vehicle. This gives a high level of information to the oncoming driver. Currently, a civilian driver sees a horizontal band along the beltline, and this is insufficient, even if it exhibits ribbon-like artwork, emblems or EKG waves.
Emblems, logos, images and company insignia are all fine as long as they are not used as a replacement for the outline tape.
By providing additional material horizontally along the upper and lower edges of the cab and chassis, the outline of the vehicle becomes apparent. They do not have to be solid lines but rather can be segmented. Our brain can add in the missing details to make it appear complete.
Why is tape color, rear chevrons and overall vehicle tape outline so important? They provide the oncoming driver with additional visual information, both day and night, in fog and smoke, and weather-induced poor visibility, because it improves reaction time. This provides for a safer driving and accident-avoidance response. The importance of improved reaction time should not be underestimated as is a vital component of emergency vehicle highway safety.