Q: One time I helped a person drive home a car that could not achieve the speed limit. The road was two-lane and curved. I put on my emergency flashers, concerned that some speeding driver would come from behind. The only car around was a WSP trooper who pulled me over and made me turn off the emergency lights. I see slow-moving trucks with their emergency lights all the time. What gives?
A: Let’s acknowledge a couple things: the misuse of hazard lamps is not why we’re having more traffic crashes, and I can’t answer on behalf of the trooper that asked you to turn them off. But I think hazard lamp laws are fascinating. (That might be the first time anyone has written that sentence.) Note that I said “laws” plural. On its own, Washington’s law on hazard lamps is pretty ordinary. Where it gets interesting is when you start comparing laws around the country.
Traffic laws are similar from state to state, but not the same. States adopted much of the Uniform Vehicle Code (created back in 1926 and updated until 2000), but they all can (and do) diverge from it. While some traffic laws are nearly identical across the country, the laws on hazard lamps are all over the place.
For example, In Alaska you’re not allowed to use your hazard lamps while driving (with a few exceptions for utility and maintenance vehicles). In California you can use them while driving to warn other drivers of an approaching hazard but not if you’re driving the vehicle creating the hazard. In Virginia you can’t use them when driving over 30 mph. In some states you can use them almost whenever you want.
Washington’s law states that hazard lamps are for “warning other operators of other vehicles of the presence of a vehicular traffic hazard requiring the exercise of unusual care in approaching, overtaking, or passing.” The law doesn’t specifically prohibit using hazard lamps if you’re the vehicle creating the hazard, so you could go with the principle that “everything which is not forbidden is allowed.” However, (and the lawyers reading this can correct me) that’s more of a concept than an actual rule of law in the US. Also, when trying to understand the law it’s not uncommon to look to other states for clarity. In this case, your conclusions could vary depending on which states you look to.
Regardless of where you come down on hazard lamps, there’s a higher principle we should consider. We have a law (in the part about speed limits) that says that obeying the speed limit isn’t enough. There’s something called due care; using a level of caution appropriate for the circumstances. Turning on your hazard lamps to avoid being rear-ended when traveling well below the speed limit on a winding road might be an example of a driver exercising due care.
Laws are useful, but not perfect. The legislators have a tough job crafting traffic code; they have to write a few sentences that apply to any possible driving situation. Then officers have to apply the laws to what they see on the roads. Maybe the trooper saw you and didn’t think you were the hazard you thought you were. I wasn’t there so I can’t say, but here’s my take: As drivers we have a limited number of ways to communicate with other road users, so if I have a tool (like hazard lamps) that helps alert other drivers of a hazard (even if it’s me) and a law can be understood two ways, like you, I’d err toward safety.