Ambulance Visibility: What You Should Know

By Jamie Thompson
EMS1 Senior Editor

A new study has highlighted best practices for emergency vehicle visibility and conspicuity but warned further research is "critically needed."

The report by the United States Fire Administration, in partnership with the International Fire Service Training Association, covers retroreflective striping and chevrons, high-visibility paint, built-in passive light, and other reflectors for EMS vehicles, fire apparatus, and law enforcement patrol vehicles.

Photo Adam ThielRetroreflective striping on GSA-compliant ambulance.

Photo Adam Thiel
Retroreflective striping on GSA-compliant ambulance.

Its key findings are:

• The increased use of retroreflective materials holds great promise for enhancing the conspicuity of emergency vehicles.

• Both visibility and recognition are important facets of emergency vehicle conspicuity.

• The use of contrasting colors can assist drivers with locating a hazard amid the visual clutter of the roadway.

• Fluorescent colors (especially fluorescent yellow-green and orange) offer higher visibility during daylight hours.

• There is limited scientific evidence that drivers are "drawn into" highly-visible emergency vehicles.

• It is theoretically possible to "over-do" the use of retroreflective materials and interfere with drivers' abilities to recognize other hazards.

• Effectiveness of the "Battenburg" pattern in the UK appears primarily related to its association with police vehicles 

The study concludes that a combination of both "active and passive" conspicuity treatments — such as enhanced emergency vehicle warning lighting systems and the increased use of retroreflective materials — will all help improve the visibility and recognizability (when desired) of emergency vehicles.

It adds that further research specific to emergency vehicle visibility and conspicuity is needed in the United States, with particular emphasis on the interaction between civilian drivers and emergency vehicles during responses and on incident scenes.

"With vehicle crashes and emergency responders being struck on the roadway being a major cause of on-duty fatalities, it is important to examine all technologies to reduce this tragic cause of death," said USFA Deputy Fire Administrator Glenn A. Gaines.

The study was supported by the U.S. Department of Justice - National Institute of Justice as part of efforts to enhance emergency vehicle and roadway operations safety for firefighters, law enforcement officers, and other emergency responders.

Aggregated data shows at least 67 EMS providers were killed in ground transportation-related events over a six-year period from 1992. Preliminary firefighter fatality statistics for last year show that 29 of 114 firefighters killed on duty died in motor vehicle crashes. In addition, more law enforcement officers have died in traffic-related incidents than from any other cause in the past 10 years.

The study also highlights potential opportunities for improving the safety of emergency vehicles using readily available products:

Photo Adam Thiel

• Outline vehicle boundaries with "contour markings" using retroreflective material, especially on large vehicles.

• Concentrate retroreflective material lower on emergency vehicles to optimize interaction with approaching vehicles' headlamps.

• Consider (and allow) the use of fluorescent retroreflective materials in applications where a high degree of day-/night-time visibility is desired.

• Using high-efficiency retroreflective material can improve conspicuity while reducing the amount of vehicle surface area requiring treatment.

• Applying distinctive logos or emblems made with retroreflective material can improve emergency vehicle visibility and recognition.

• For law enforcement vehicles, retroreflective material can be concentrated on the rear to maintain stealth when facing traffic or patrolling.

The latest revision to NFPA 1901 Standard for Motorized Fire Apparatus became effective in January, requiring retroreflective striping in multiple locations on new fire trucks.

In August 2007, the U.S. General Services Administration published the latest edition of its KKK-A-1822F Federal Specification for the Star-of-Life Ambulance. While it is not completely applicable to every ambulance operated in the United States, the GSA standard (also known as the "Triple-K spec") outlines conspicuity specifications for the basic ambulance livery.

In addition, with about 60 percent of fire departments providing EMS, the NFPA has formed a committee to write standards for ambulance design.

"NFPA 1901 did a terrific job in increasing the visibility and conspicuity requirements for new fire apparatus, and I would imagine this area could be explored in its standards for ambulances," said Bill Troup, fire program specialist at the USFA.

Sheeting materials
One of the key findings on retroreflective materials in the study was the apparent confirmation that properly applied and maintained retroreflective sheeting materials can effectively increase the nighttime visibility and conspicuity of treated objects.

"While generalizing practices (without rigorous evaluation) used in other disciplines and/or countries remains a concern, the current research suggests that leveraging the properties of readily available retroreflective sheeting products, by incorporating them into U.S. emergency vehicle designs, appears promising for enhancing emergency vehicle visibility and conspicuity, especially during dark lighting conditions," it said.

The study said there is limited scientific evidence to support the notion of the "moth effect" — that drivers steer toward bright lights such as those used to increase the visibility of emergency vehicles like "moths to a flame."

However, several recent studies suggest that while bright lights may not be the cause, drivers' fixation on roadside objects can cause their steering to drift in the direction of their gaze, according to the study.

"This effect may be more pronounced with other impairments," it said. "The implications of these findings on emergency vehicle visibility/conspicuity are unknown, but certainly support the need for additional research on how to design passive conspicuity treatments so they draw drivers’ attention enough to induce the appropriate ("stay away") response, without causing the potentially negative results of visual fixation," said the report.

The study was put together by a panel of experts spanning public safety and relevant manufacturers, and included Robert Tutterow, vice president of the Fire Industry Equipment Research Organization and health and safety officer at the Charlotte, N.C., Fire Department.

Tutterow, who also sits on the NFPA 1901 committee, said the study provides good baseline knowledge to enable further research, and confirms the importance of several key areas such as daytime visibility fluorescent colors.

He said the importance of emergency vehicle visibility and conspicuity on roadways is more vital today than it ever has been. "Drivers in cars are more distracted nowadays with mobile phones, GPS and entertainment systems," Tutterow said. "They are focused on everything but driving, which really highlights the importance of this study."


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