Configuring a custom light bar setup for an emergency vehicle involves more than choosing a size and color. It's critical to ensure that the product format, mounting position, color combination, SAE class rating, and control system all work together to produce a compliant, effective warning system. Whether you are outfitting a police vehicle, a fire truck, a tow truck, or a construction fleet, the decisions you make in the planning and configuration stage will determine how well the system performs in the field and whether the system meets the legal requirements for your jurisdiction.

This guide walks through the key configuration decisions for custom emergency vehicle light bars, including the SAE and color rules that govern these lights and how to match the right product types to your specific vehicle and role.

What "Custom" Means for Emergency Vehicle Light Bars

A custom emergency vehicle lighting setup does not mean that you are using custom-manufactured hardware. Instead, this process involves selecting, combining, and configuring off-the-shelf SAE-certified products to match the specific requirements of your vehicle type, role, jurisdiction, and mounting. The customization happens at four levels:

SAE Certification: The Non-Negotiable Starting Point

Every warning light in a custom emergency vehicle setup must comply with SAE J845 (for omnidirectional 360° warning devices such as light bars, mini bars, beacons) or SAE J595 (for directional surface-mounted units such as grille lights or stick bars). Both standards define three intensity classes:

Both standards require a flash rate of 60–120 flashes per minute (FPM). Always verify the SAE class printed on the product specification against your state's requirements for your vehicle type before purchasing.

Color Configuration: What Colors Are Permitted for Your Vehicle

Color is the most legally sensitive decision you'll make for your light bar configuration. Red and blue lights are restricted to authorized emergency vehicles in virtually every U.S. state. Using prohibited colors on a non-authorized vehicle can result in fines, confiscation, or criminal charges. Here is the standard framework across most jurisdictions:

Always verify your state's specific color restrictions with the authority having jurisdiction (AHJ) before finalizing your configuration. Multi-color LED units that contain red or blue LEDs must not be installed on non-authorized vehicles, even if those colors are not actively used.

Custom Light Bar Product Types: Choosing the Right Format

The product format determines where the light is mounted, how visible it is, and what zone coverage it provides. Most custom setups combine two or more types of light bars to achieve full zone coverage:

Full-Size Light Bars

At 36–75 inches, full-size light bars are the primary warning unit for most truck-level builds. They are mounted on the roof or cab and cover both the front and rear warning zones simultaneously. Most models include a built-in amber traffic advisor in the rear section, or multi-color models that allow the bar to switch between the primary warning color and amber on demand. These full-size bars are standard for police cruisers, fire trucks, and tow trucks.

Mini Light Bars

At 14–27 inches, mini light bars offer a compact rooftop or cab-mounted solution for vehicles where a full-size bar is impractical. These light bars are often installed in pickup trucks, SUVs, supervisory vehicles, and service vans. SAE Class 1 options are available. Magnetic-mount models allow for quick deployment and removal. They are a common choice for volunteer firefighters and utility supervisors who need capable warning output without a full vehicle profile.

Surface Mount / Grille Lights

Surface mount lights are installed in the grille, bumper, or running board positions to fill warning zones that a rooftop bar cannot cover, especially in the front and side zones. They are also the standard product for builds where a rooftop bar is not used, such as unmarked vehicles with grille-and-dash setups. SAE J595 governs these units.

Hideaway Kits

Hideaway kits are installed with compact LED modules inside existing headlight and taillight housings, making them invisible when not in use. They are the standard configuration for slick-top and unmarked vehicles, including unmarked police, fire police, supervisory cars, and similar roles. When activated, they flash through the lens in the lens color. No exterior hardware modification required.

Traffic Advisor Stick Bars

A rear-mounted traffic advisor provides directional arrow patterns to guide traffic around the vehicle. It is a separate unit from the primary light bar and is essential for any vehicle involved in lane closures or roadside scenes. Traffic advisors come as standalone units or can be integrated into full-size bars. Amber is the standard color for all traffic direction functions.

Switch Boxes & Controllers

A switch box and control panel consolidate all warning functions into a single cab-mounted interface. Each button controls a specific zone or function independently: primary bar, traffic advisor, grille lights, and takedown lights. Make sure to choose the right controller for the number of outputs in your setup to ensure that everything can be configured correctly.

Configuration Guide by Vehicle Type

Zone Coverage: Making Sure All Four Zones Are Addressed

NFPA 1900 (effective January 1, 2024) defines minimum warning zone coverage requirements for fire trucks. Consult your upfitter to confirm compliance for any new fire vehicle purchase or retrofit.

Frequently Asked Questions

What does "custom" mean for emergency vehicle light bars?

In the context of emergency vehicle lighting, "custom" refers to the process of selecting, combining, and configuring SAE-certified products to match your specific vehicle, role, jurisdiction, and mounting geometry. "Custom" lighting doesn't mean custom-manufactured hardware. There are different configuration decisions that need to be addressed for product format, color selection, zone coverage, and the control system.

Do I need different SAE certifications for different parts of the setup?

Yes. Omnidirectional units (light bars, mini bars, beacons) fall under SAE J845. Directional surface-mounted units (grille lights, stick bars, hideaway kits) fall under SAE J595. A complete setup often includes both types, and each product should carry the appropriate SAE certification for its category. Always check the product specification for the SAE standard and class before purchasing.

Can I mix colors in a single light bar setup?

Yes, colors can be mixed as long as they are legally permitted for your vehicle type. For example, a police setup might use a red-and-blue primary bar with white takedown lights. A fire truck might use a red primary bar with an amber traffic advisor. The key constraint is that prohibited colors (most commonly red or blue on non-authorized vehicles) cannot be included, even if they are not actively used.

What is the difference between a full-size bar and a mini bar for emergency vehicles?

Full-size bars (36–75 inches) provide the highest LED count and broadest front-to-rear coverage from a single rooftop unit. They are the standard for vehicle-level builds, including police cruisers, fire trucks, ambulances, and tow trucks. Mini bars (14–27 inches) are compact alternatives that provide effective warning output in a lower-profile format. They are commonly used on pickup trucks, SUVs, supervisory vehicles, and any build where rooftop space is limited.

When should I use hideaway kits instead of surface mount lights?

Hideaway kits are the right choice for any vehicle where no exterior warning hardware should be visible when the lights are not in use, such as unmarked police vehicles, fire police, supervisory cars, or any slick-top build. Surface mount lights are the right choice when the vehicle needs visible exterior hardware in specific zones (grille, bumper, or running board positions) and concealment is not a priority.

How do I control all the lights in a multi-zone setup?

A switch box and controller setup consolidates all warning functions into a single cab-mounted panel. Each output button independently controls a zone or function, including the primary bar, traffic advisor, grille lights, dash lights, and takedown lights. The controller must have enough outputs to match the number of independently operated light groups in your setup.

What IP rating do I need for exterior-mounted emergency vehicle lights?

All exterior-mounted lights should carry at minimum an IP67 rating: fully dust-tight and waterproof to 1-meter immersion for 30 minutes. For low-mount positions (bumper, running board, undercarriage) that are directly exposed to water spray and road debris, IP-rated products are the better choice. Interior-mounted products such as hideaway kits and dash bars do not require high IP ratings since the cabin provides natural weather protection.