Editor’s note: This article is part of Police1’s Vehicles Week, which explores how patrol vehicles have become one of the most important tools officers use every shift. Throughout the series, we’ll examine vehicle interiors, fleet trends, officer feedback and practical resources to better understand how today’s patrol vehicles are evolving to support policing. Thanks to our Vehicles Week sponsor, Setina.
By John Hearne
One constant in policing is the reliance on warning lights to help officers do their jobs safely. Opinions and laws governing emergency lighting vary by jurisdiction. For that reason, this article isn’t intended to tell you exactly what to do. Instead, it shares observations from more than 30 years of operating, building and writing technical specifications for law enforcement vehicles. Some of these mistakes can significantly affect officer safety, while others are small details that are often overlooked.
Before going too far, it’s important to recognize that police lighting should fulfill multiple purposes. These include:
- Requesting the right of way during an emergency response.
- Notifying the public of a stopped police vehicle and the need to safely pass it.
- Identifying the vehicle as a law enforcement vehicle to heighten public awareness.
- Providing auxiliary lighting to illuminate scenes or enhance officer safety by temporarily blinding suspects.
Many common errors result from overemphasizing one of these needs at the expense of the others. Lights and sirens should be selected and installed with all of these functions in mind, not simply based on what is cheapest or what looks the “coolest.”
Poor flash patterns
Modern warning lights offer a variety of flash and steady-burn patterns. One of the most common mistakes is using the same pattern for every situation. Having one pattern for a vehicle in motion and another for a parked vehicle is a better way to balance the competing roles of emergency lighting. Better yet, consider a third configuration for when the vehicle is responding with both lights and siren activated.
When evaluating warning lights, it’s common to stand only a few feet from the vehicle and choose the fastest flash patterns because they look impressive. A much better test is to park the vehicle farther away and drive toward it. What looks good at 20 feet may not be nearly as effective when viewed from 200 yards away. Years of experience have shown that, for a parked vehicle, flashing all of the lights on and off at once (synchronized) is more effective than having multiple lights flash randomly.
With many lightheads capable of producing more than one color, another effect of flashing too quickly is that the colors blur together. Flashing red and blue lights in rapid succession can make them appear purple at a distance. If you’re going to alternate colors within a flash pattern, use a slower sequence that gives the eye time to recognize each color. It’s been said that much of music is the space between the notes. The same is true of effective warning lighting. Allowing the lights to remain “off” long enough between flashes can make them easier to recognize.
Related to flash patterns is the largely forgotten steady-burn light. While a forward-facing steady-burn light is required by law in California, research and field experience suggest it should be used more often, especially for stationary vehicles. Once a vehicle is no longer in motion, the most important information to convey is its location. Because a steady-burn light isn’t flashing, it appears to be easier for the human eye to track, helping approaching drivers safely maneuver around the vehicle.
If your state allows you to choose warning-light colors, available research suggests that red and blue provide the most effective combination. Red is generally more visible during daylight conditions, while blue performs better at night or in fog and smoke. For reasons unrelated to officer safety, some agencies continue to reject this combination or refuse to incorporate amber traffic advisors despite their well-documented advantages.
Blocked light considerations
Even the best warning lights cannot do their job if they are blocked from view.
The classic example is a sedan equipped with a roof-mounted lightbar. When the trunk is opened, the trunk lid can completely obstruct the lightbar, reducing visibility for approaching traffic. This has contributed to crashes and, in some cases, officer fatalities. Installing two warning lights in the trunk that remain visible when the lid is open is a simple solution.
A similar problem can occur with an internal lightbar mounted behind the rear glass of an SUV. Raising the hatch directs those lights upward instead of toward approaching traffic.
Another concern involves SUVs equipped with an external roof-mounted lightbar. When the vehicle is parked on a hill, drivers approaching from below may not see the lightbar because the rear of the vehicle blocks it. Mounting additional rear-facing lights lower on the vehicle helps solve this problem.
Putting lights behind tint
There are many reasons to tint a police vehicle’s windows. Tint serves an important purpose by reducing the amount of light entering the vehicle. However, it also reduces the amount of light leaving the vehicle when warning lights are mounted behind the glass. Even the most effective warning light can lose much of its output when mounted behind heavy tint.
There are several ways to avoid this problem. Some vehicle manufacturers offer the option to delete the tint at the top of the windshield, which is especially useful if you plan to mount an internal lightbar. Another option is to cut away the tint directly in front of the light. This works particularly well for lights mounted on the rear deck of a sedan. Simply leaving the bottom few inches of the rear window untinted allows the lights to operate at full intensity.
Another solution is to move the light outside the vehicle. Instead of mounting a light behind the heavily tinted C- or D-pillar glass on an SUV, consider mounting it externally above the rear wheel.
If mounting behind tint can’t be avoided, using a lighthead with more LEDs can help compensate for the reduced output. Some manufacturers also offer lenses that focus the light into a narrower beam rather than dispersing it broadly, allowing more light to project through tinted glass.
Poor light mounting
Emergency lightheads are designed to project most of their light straight ahead while also providing some off-axis visibility. For that reason, they should be mounted as close to perpendicular to the roadway as possible. Lights mounted at steep upward or downward angles won’t reach full intensity for approaching motorists until the last second.
Orientation also matters. Most lightheads are designed with a horizontal beam pattern. Rotating them vertically changes that pattern, sending more light into the trees or onto the roadway instead of toward approaching traffic.
While the major manufacturers of emergency warning equipment produce excellent lights, their mounting options aren’t always ideal for every application. Several aftermarket companies have developed innovative mounting solutions that position lights more effectively. In some cases, achieving the best result means combining one manufacturer’s lights with another company’s mounting hardware.
Intersection warning
Related to light mounting is the often-overlooked issue of intersection warning. Intersections remain the most common location for crashes during emergency responses. Despite that risk, many agencies equip their vehicles with numerous front- and rear-facing lights but provide minimal warning to the sides.
Depending on whether the vehicle has an external lightbar, agencies should consider mounting at least two warning lights on each side of the vehicle. The first should be positioned near the part of the vehicle entering the intersection first, typically on the side of the push bumper. A second light mounted farther back improves visibility not only at intersections but also when the vehicle is parked sideways to block a roadway or while making a U-turn.
Traffic advisors/arrows
One of the most useful tools for improving the safety of a parked patrol vehicle is the traffic advisor, sometimes called a traffic arrow. These devices use a moving sequence of lights to direct traffic to the left or right of the vehicle while also providing an additional rear-facing warning signal.
Like any warning device, however, they must be installed correctly.
A common mistake is mounting the traffic advisor within the lightbar or relying solely on the traffic advisor function built into the lightbar. Traffic advisors and flashing warning lights communicate different messages, so they should be physically separated to make each one easier for approaching motorists to recognize.
For example, on a sedan equipped with a roof-mounted lightbar, mounting the traffic advisor on the rear deck provides adequate separation. On an SUV, the most effective configuration is often to mount the flashing warning lights on the rear of the vehicle and the traffic advisor higher on the vehicle.
Final thoughts
Effective warning lighting depends on more than simply installing bright lights. Flash patterns, warning-light colors, mounting locations and proper placement all influence how quickly motorists recognize an emergency vehicle and respond safely.
Taking the time to evaluate these details during the upfit process can improve officer safety and help agencies get the most from their emergency warning systems.
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About the author
John Hearne is a retired federal law enforcement officer whose public safety career spanned more than 35 years. For more than 20 years, he designed, built and specified equipment for emergency vehicles, ultimately serving on his agency’s national advisory board on vehicle equipment. He was also an early tester and adopter of smart vehicle controller systems.
