Kayak Overhang, Flag and Light Laws

Check your state’s current vehicle code before driving with a kayak that extends beyond your car. That projecting part of the load is your overhang. Check the maximum permitted projection separately from the point at which flags, lamps or reflectors become required. Washington’s code illustrates why these are separate checks: adding a flag does not establish permission to carry a longer load.¹²

Repeat the check for every state on your route. This article is not legal advice. If the wording or measurement is unclear, ask the state Department of Motor Vehicles (DMV) or State Patrol (the state highway police) which current sections apply to your vehicle and carrying arrangement.

This page summarizes published safety guidance. It is not a substitute for instruction, and conditions on your water may differ. Check the current rules for the state and water you paddle.

Key Takeaways

Check the current vehicle code for each state you will drive through.
Find the permitted projection before choosing a flag or light.
Measure from the part of the vehicle named in each rule—its measurement point.
Record flag, lamp and reflector requirements separately.
Ask the state DMV or State Patrol about wording you cannot confidently apply.

What an overhang rule covers

An overhang rule governs a load extending beyond a vehicle. For this task, the state vehicle code is the place to start. State legislatures enact the laws; agency guidance can help you find and understand them. Washington’s legislature describes its code as the compilation of current state laws and says it is updated annually to reflect enacted changes.³

Look for these categories rather than assuming one number answers everything:

Projection limits: how far the load may extend forward, backward or sideways.
Flag requirements: the threshold, color, size and placement.
Lighting requirements: lamps, reflectors, visibility distances and placement.
Lighting conditions: the times and visibility conditions that activate those requirements.

Washington’s separate projection, marking and lighting provisions demonstrate these categories. Their measurement points and thresholds differ, even within the same state.²¹⁴

Washington: one example of how the wording matters

Washington’s projecting-load statute, RCW 46.37.140, has an official PDF certified on July 12, 2024. Its current HTML was checked on October 13, 2026. The certification date is a document date, not a claim that the law changed that day.¹⁵

Check the maximum projection first

For a vehicle operated alone on Washington’s public highways, RCW 46.44.034 generally limits front projection to three feet beyond the front wheels, or beyond the front bumper when the vehicle has one. Its general rear limit prohibits a load extending more than fifteen feet beyond the center of the last axle. An axle is the assembly at a pair of wheels; here, the last axle identifies the rearmost wheel position used for measurement.²

These are the provisions for the ordinary single-vehicle setup considered here. Read the current section for your arrangement, especially if you use a trailer.

For passenger-type vehicles on public highways, RCW 46.44.060 prohibits a load extending beyond the line of the fenders on the left side or more than six inches beyond the line of the fenders on the right side. Measure the rear maximum from the center of the last axle, flag projection beyond the vehicle’s sides or rear, and rear lamp and reflector projection beyond its bed or body—the pickup’s cargo bed or the car’s body.²¹

Check flags separately

Washington requires flags when a load projects more than four inches beyond the vehicle’s sides or more than four feet beyond its rear. The statute specifies:

“red or orange fluorescent warning flags, not less than eighteen inches square, marking the extremities of such loads.”¹

“Fluorescent” describes a vivid color that appears especially bright in daylight. The extremities are the load’s outermost ends or edges. Keep the words “more than” in your notes: the rear flag threshold is not worded the same way as the rear lighting threshold.¹

Check lamps and reflectors

Washington’s rear lighting provision applies when a load extends four feet or more beyond the vehicle’s bed or body, at the lighting times specified in RCW 46.37.020. It requires the following at the extreme rear end of the load:¹

Two red lamps visible from at least five hundred feet behind the load.
Two red reflectors visible at night throughout the range from one hundred to six hundred feet behind the load when directly illuminated by headlights set to low beam and meeting legal requirements. They must indicate the load’s maximum width.
A red lamp on each side, visible from at least five hundred feet to that side and positioned to indicate the maximum overhang.¹

A reflector returns light from another vehicle’s headlights; the statute lists it separately from a lamp. Describing this requirement as simply “a red light at night” would leave out required equipment and placement.¹

Washington’s lighting times run from half an hour after sunset to half an hour before sunrise. They also include insufficient light or weather that reduces visibility so people and vehicles are not clearly visible one thousand feet ahead.⁴

For a moving vehicle, check both the time and visibility conditions. Treat flags and lighting as separate duties when reading the code.

Do federal rules give your personal car an allowance?

The federal provisions discussed here do not supply a national overhang allowance for an ordinary personal car carrying a kayak.

The Federal Motor Carrier Safety Administration’s warning-flag rule, 49 CFR 393.87, covers a legally defined category of vehicles used in commercial transport. The equipment rules in that part apply to vehicles meeting that definition.⁶⁷

The general applicability section includes commercial motor vehicles transporting property or passengers in interstate commerce—commercial transport between states. Unless otherwise specifically provided, it excludes occasional transportation of personal property by individuals when it is neither for compensation nor in furtherance of a commercial enterprise.⁸

A separate federal provision concerns specialized boat transporters. Its definition describes vehicle combinations designed and used specifically to transport assembled boats and boat hulls. A kayak on a passenger car’s roof does not, by itself, fit that definition. Do not use the transporter provision as your car’s permitted projection.⁹¹⁰

How to look up your route’s rules

Work through the applicable code, measurement points, marking requirements and lighting conditions in that order. This checklist is a practical reading method based on the distinctions in Washington’s provisions.²¹⁴

Find the official pages. Search your state’s legislature, DMV or State Patrol website for “projecting load,” “overhang,” “flags” and “lights.” Repeat for each state on your route.
Confirm the vehicle covered. Open the current code section and check whether it applies to your passenger car, pickup or trailer arrangement. Keep commercial permit guidance separate from the provisions applying to your setup.
Record the projection limits. Write down front, rear and side limits and each measurement reference. Measure your loaded setup from that point; do not automatically use the bumper or the end of the roof rack.
Record the marking requirements. Preserve “more than” versus “or more.” Note flag color, dimensions and placement, along with every required lamp and reflector.
Follow the lighting references. Read the linked section for time and poor-visibility conditions. Note the document date and check for amendments.
Resolve uncertainty before driving. Give the DMV or State Patrol your vehicle type, carrying arrangement, measured projection and expected lighting conditions. Ask which current sections apply. Washington’s State Patrol provides an equipment-inquiry contact on its vehicle requirements page.¹¹

Where next

Use the care and transport guide to plan the rest of your setup. For securing the load, read how to tie down a kayak. If your arrangement involves additional boats or towing, continue to carrying two or more kayaks or kayak trailers.