Barrier Lights and Traffic Barricade Lights: Type A, B, C and D

Barrier lights (also sold as traffic barricade lights) are the small yellow, battery-powered lights that clip onto drums, barricades, signs and barriers. The MUTCD sorts them into four types: Type A flashes at low intensity for night work, Type B flashes at high intensity day and night, and Types C and D burn steady to outline the path at night.

Type	Mode	When it's used	Must be visible from
A, low-intensity flashing	Flashing	At night, on a device standing alone or in a cluster to warn of a hazard	3,000 ft on a clear night
B, high-intensity flashing	Flashing	Day and night, usually on advance warning signs or their own stand	1,000 ft on a sunny day
C, steady-burn	Steady	At night, on a line of devices to show the edge of the path	3,000 ft on a clear night
D, 360-degree steady-burn	Steady, all around	Same as C, seen from every side	3,000 ft on a clear night

Source: MUTCD 6L.07. All four are yellow, lens-directed and enclosed, and they must meet the ITE equipment standard the manual names.

Flashing or steady: the rule people get wrong

A row of flashing lights doesn't show drivers a path. It shows them a lot of blinking. That's why Section 6L.07 is strict:

• On devices used alone or in a cluster to warn of a condition, lights flash.
• On devices used in a series to channelize traffic, lights burn steady (Type C or D).
• The one exception: sequential flashing lights on the devices of a merging taper, flashing in order from the upstream end to the downstream end, each 55 to 75 times a minute.

Where a curve is involved, steady lights go only on the devices on the outside of the curve.

Mounting

• At least 30 inches from the road to the bottom of the lens.
• Mounted so that if a car hits the device, the light won't go through the windshield. Use the bracket the maker sells for that device.
• On signs, a light can't cover the sign face.
• On temporary concrete or steel barrier, the MUTCD's option is steady-burn lights (6M.02). A line of lights along a barrier that guides traffic burns steady anyway (6L.07).

How many lights you need

The maximum spacing for warning lights is the same as for the devices they sit on (6L.07). In practice that means one light per device in the taper and along the work area, plus Type B lights on the advance warning signs if your plan calls for them. Use the calculator below to count devices, then add lights for each sign that gets one.

Batteries, LEDs and photocells

Nearly every light sold now is LED. Most run on one or two 6-volt lantern batteries, some on 12-volt packs, and some on a small solar panel with a rechargeable cell. A photocell turns the light on at dusk and off at dawn, which saves batteries on day-only Type A and C lights. Type B lights run around the clock, so check the rated run time, not just the price.

Two buying tips:

1. Buy one battery type for the whole fleet. Mixed lights mean mixed batteries on the truck, and dead lights.
2. Check the lens color and type against the job. Airport work uses red lights, not yellow ones. See airport barricade lights.

Mistakes we see on orders

• Flashing lights along a taper. Use steady-burn, or a true sequential system.
• Type A lights on advance warning signs for a day job. Type A is a night light. Signs that need a light in daylight get Type B.
• Lights mounted below 30 inches. Common on short cones; it's not allowed.
• Lights on the inside of a curve. Outside only.

What it costs

Ballpark U.S. prices in late 2026: $15 to $40 for a Type A or Type C LED light, $60 to $160 for a Type B, and $40 to $120 for a solar light. Batteries add $8 to $15 per light per change.

Where to buy

Traffic safety distributors and barricade rental companies. Ask for the type designation in writing and for the light's rated run time on one set of batteries.