Rules of the Road

Driving well below the speed limit? You may want to brush up on the law

There is a law that addresses vehicles traveling a lot slower than the posted speed limit.
There is a law that addresses vehicles traveling a lot slower than the posted speed limit.

Question: The speed limit on Mount Baker Highway is 55 mph. Often in the mornings I am stuck behind a person driving a scooter with a max speed of 40. Sometimes they drive on the shoulder; more times they drive in the lane.

This creates an unsafe environment as speeding trucks and cars quickly approach and have to slam on their breaks to avoid a collision. Are scooters allowed on Mount Baker Highway?

Answer: I agree with you about the danger of slow-moving vehicles on high speed limit roadways. Speed differential (the difference between the speeds of vehicles traveling on the same section of roadway) creates all kinds of mayhem.

As drivers, we expect consistent behavior from each other – a signal before turning, functional brake lights, and speeds somewhere close to the posted limit.

As I write this there are several inches of snow on the ground, so I’ll add the caveat that speed should be tempered by road conditions. Ice, snow, fog and rain are all good reasons to travel at a slower and safer speed.

Assuming good road conditions, most drivers don’t anticipate encountering a vehicle traveling 15 mph slower than the rest of traffic, and that can, as you mentioned, result in rear-end collisions, or at least some close calls.

We’ve established that it’s not a good idea to drive a vehicle with a top speed of 40 mph on a road with a posted limit of 55 mph. But is it legal?

The Revised Code of Washington has a couple of laws on the topic. Many people are familiar with the five-car rule. This is the law that states that if you’re traveling on a two-lane road slower than the rest of traffic, and you have five or more vehicles behind you, you’re required to pull over and let them pass. This law applies to all vehicles, which includes bicycles.

There is also a law that addresses vehicles traveling a lot slower than the speed limit, like the scooter on Mount Baker Highway. RCW 46.61.425 states that “No person shall drive a motor vehicle at such a slow speed as to impede the normal and reasonable movement of traffic ...”

The law goes on to give some exceptions for safety, but basically, if your vehicle can’t come close to the speed limit of a given road, you’re not allowed to drive it on that road. This one only applies to motor vehicles, so bikes are not included.

However, there is a law that requires cyclists to ride as far to the right as is safe when traveling slower than the normal flow of traffic. Whether you’re a cyclist or a driver, keep in mind that it’s not “as far right as possible,” but “as far right as is safe.”

Washington law doesn’t use the term “scooter” to describe the vehicle we’re discussing. Instead, it has several categories of two-wheeled vehicles, two of which could apply.

A scooter fits the legal description of either a motor-driven cycle or a motorcycle. What’s the difference? Mostly power. A motor-driven cycle cannot exceed five horsepower. Since the top speed of a five horsepower vehicle is not even close to 55 mph, Mount Baker Highway is clearly off-limits for a motor-driven cycle.

Like a motorcycle, a motor-driven cycle requires an additional license endorsement. This is different from a moped, which only requires a driver’s license for operation. What’s the difference between a motor-driven cycle and a moped? Again, mostly power. A moped must have an engine no bigger than 50 cubic centimeters and produce no more than two horsepower.

As long as I’m digging into two-wheel legal trivia, there is a category that includes the term “scooter” as part of the title. It is called a “motorized foot scooter.” This is essentially a stand-up kick scooter with a motor. It is limited to a top speed of 20 mph and doesn’t require any kind of license to ride.

Road Rules is a regular column on road laws, safe driving habits and general police practices. Doug Dahl is the Target Zero Manager for the Whatcom County Traffic Safety Task Force. Target Zero is Washington’s vision to reduce traffic fatalities and serious injuries to zero by 2030. For more traffic safety information visit Ask a question.