Why Do Some Pickup Trucks Have Lights On The Roof? Here's What They're For.

It's not uncommon to see pickup trucks with either factory-installed or aftermarket lights on their roofs on American roads, although they may appear intimidating and perplexing to those unaware of their use. These lights are called clearance lamps or cab marker lights, and they actually serve various purposes. Many heavy-duty pickup trucks come equipped with this feature as part of their standard or optional trim packages. For instance, the Ford F-450 Super Duty models have them as standard. Some trims of the Ram 2500 and 3500 and the Chevrolet Silverado 2500HD and 3500HD also have them as standard, while the other trims can have the lights added for an additional price. 

Cab marker lights are more often than not added not for their aesthetic appeal but because of federal regulations. The Federal Motor Vehicle Safety Standards (FMVSS) indicate that vehicles over 80 inches (2032 mm) in width must have clearance lamps to improve their visibility to other drivers, particularly in low-light conditions. Because of this directive, larger pickup trucks, including the dually models, have these lights on the roof as a standard safety feature. Though the rule does not apply to smaller pickup trucks, like the Chevrolet Colorado, whose 2025 model we recently reviewed, and the feature-packed Toyota Tacoma, owners can still choose to install them for stylistic and practical reasons.

Large pickup trucks, including dually trucks, occupy a lot of space on the road. Hence, it could be a struggle for nearby vehicles to estimate their size and position at night, even with their headlights and taillights on. The main purpose of clearance lamps on large pickups, as mandated by federal authorities, is to improve vehicular visibility. The lights give other vehicles an idea of the truck's height and width at night or in adverse weather conditions. The amber-colored cab marker lights, which are installed on the front, help indicate the width, while the red clearance lamps, typically placed on the rear, also serve the same function. Both are useful for preventing accidents in poor visibility scenarios, such as fog or heavy rain.

Apart from their regulatory purpose, these roof-mounted lights can also serve practical and aesthetic roles. Many pickup truck enthusiasts install aftermarket LED clearance lights to enhance their vehicles' rugged, off-road-ready appearance compared to the standard package. Additionally, some off-road or work-oriented pickup trucks, such as the Ford F-450 Super Duty or Ram Heavy Duty models used by the police, may upgrade to roof-mounted light bars for increased forward illumination in the dark. Meanwhile, utility companies and emergency response teams rely on clearance lamps to ensure their vehicles remain visible while workers perform roadside tasks, especially at night.

If your pickup truck does not come with roof marker lights as standard and your dealership offers them as an option at a hefty price, or if your old roof-mounted lamps need replacing, you may opt to buy a set from online marketplaces. Amazon has a huge selection of clearance lights for different heavy-duty pickup models. One credible option is the pack of five amber smoked top cab clearance lights from Shinefit, which retails for $65.99. These easy-to-install LED lights are compatible with a variety of trucks and have a fully sealed design, so they lock out moisture during rainy days.

A brand called Nilight offers round red LED clearance lights with 60-lumen brightness — a pack of 10 retails for $9.95 and has earned the Amazon's Choice badge for its competitive pricing and high ratings. It has a sustainability certification for being made of recycled plastics and bio-based materials. When you buy a set, you are getting two-wire leads, with black for ground or negative and red for positive, alongside the round lights. Each light is covered in rubber for waterproofing and can be mounted not only on the roof but also on the side and rear as clearance or marker lights.