Clearance & Marker Lights - Incandescent

What Are Incandescent Clearance & Marker Lights?

When you're towing a trailer, hauling a boat, or rolling down the highway in an RV, one of the most critical safety systems on your rig is also one of the easiest to overlook: clearance and marker lights. Clearance lights are typically mounted on the top corners and sides of a trailer or RV, while side marker lights run along the length of the vehicle. Together, they form a lighting outline that tells other drivers exactly how wide and long your rig is — information that's indispensable at night or in low-visibility conditions.

Incandescent clearance and marker lights use a traditional bulb-and-filament design that has been trusted in the trailering industry for decades. They produce the warm amber and red glow familiar on countless trailers, boat haulers, and RVs. One key advantage of incandescent units is their straightforward repairability — in most cases, lenses are removable and bulbs are easy to swap without replacing the entire housing, making roadside fixes simple and economical.

Why Proper Clearance & Marker Lighting Matters

Federal regulations require trailers and large vehicles over a certain width to be equipped with functioning clearance and marker lights. But beyond legal compliance, these lights play a direct role in road safety. In low-light conditions, other drivers depend on clearance and marker lights to gauge the shape and size of your trailer, helping them judge safe passing distances and merge decisions. A burned-out or missing marker light can create a dangerous blind spot for drivers sharing the road with you.

Regular inspection of your incandescent marker and clearance lights is essential — especially before long trips or after boat trailer submersion. Because incandescent bulbs rely on a filament, they can fail from vibration or moisture over time. Many incandescent units in this category are built with sealed, waterproof housings to combat the harsh conditions of marine trailering and highway towing.

Key Considerations When Shopping

• Color: Amber lights are required on the front and sides; red lights are used on the rear. Always verify the correct color for your mounting location.
• Mount Type: Surface mount, ear mount, stud mount, and grommet mount options exist — match the mount to your trailer's existing hardware for a clean, secure fit.
• Lens Replaceability: Look for units with user-removable lenses so you can swap a burnt bulb without buying a whole new light assembly.
• Waterproofing: For boat trailers that regularly submerge during launch and retrieval, choose units with permanently sealed compartments or waterproof-rated housings.
• DOT Compliance: Ensure the lights meet Federal Motor Vehicle Safety Standards for your trailer type and width.

Top Brands in Incandescent Clearance & Marker Lights

Optronics is one of the most recognized names in trailer and RV lighting, offering an extensive lineup of marker and clearance lights for commercial vehicles, cargo trailers, and recreational applications. Their incandescent units feature durable polycarbonate lenses and sealed waterproof housings, with multiple mounting and wiring options to suit a wide variety of trailer configurations.

Anderson Manufacturing has long been a go-to brand for boat trailer lighting, with clearance and side marker lights engineered specifically for the demands of marine use. Anderson's incandescent offerings are known for their rugged construction and wide availability, making them a practical choice for both new installations and like-for-like replacements.

Wesbar has been producing trailer lighting solutions since 1934, building a reputation on waterproof, sealed, and shock-resistant construction. Their incandescent clearance and marker lights are a popular choice for boat trailer applications, featuring quick-connect wiring methods and all-weather designs with replaceable lenses for easy maintenance.