"Vehicle Conspicuity" refers to the degree to which an emergency vehicle can be easily seen and recognized by the human eye, in direct and peripheral vision. Cutting edge research in the emergency response industry recommends several changes to emergency vehicle design: (1) the use of large contrasting blocks of color; (2) the use of highly reflective materials; (3) outlining the vehicle in retro-reflective material; and (4) the application of large chevrons of alternating, contrasting colors to the rear of the vehicle.
Aetna was the first in the state of Connecticut to use the large, contrasting blocks of color known as "Battenburg" design which are in use across Europe. For example, the world's largest EMS agency, London Ambulance Service, converted their entire fleet to this design in 2004. They achieved a vast improvement in crew safety through a decrease in emergency vehicle accidents. This decrease was found while the vehicle was traveling or stationary (parked on the scene of EMS calls).