Tailgating – How Close is Too Close?

Q: Is it just me, or is there is a tailgating epidemic happening in Whatcom County? It seems like it’s happening all the time. Why aren’t the cops enforcing it?

A: I hear variations of this question a lot. Tailgating is definitely a problem. (I should mention that while I, and most people, use the term “tailgating,” the legal term is “following too closely.”)  Last year over 300 crashes in Whatcom County were attributed to following too closely. Is it an epidemic? The dictionary defines an epidemic as “a widespread occurrence of an infectious disease in a community at a particular time.” I don’t think it’s infectious, but tailgating is a widespread occurrence happening right now in our community, so if two out of three is still a win, then yes, it’s an epidemic.

Part two of the question asks why the cops aren’t enforcing it. To answer that question, I got myself invited to ride in the passenger seat of a Whatcom County deputy’s patrol car to interview him while he did some tailgating enforcement. You can probably see where this is going; the cops are doing enforcement, but you wouldn’t know it based on the behavior of many drivers.

It turns out that the tailgaters often don’t realize they’re committing a traffic violation. When drivers were asked about safe following distances, responses included “I don’t know” and “ten feet.” We tend to think of tailgaters as aggressive drivers, but most of the time they’re unaware; equally dangerous but without the hostile motive.

If the answer is not “ten feet,” then how close is too close? The Revised Code of Washington states that “the driver of a motor vehicle shall not follow another vehicle more closely than is reasonable and prudent.” That answer may seem nebulous, but “reasonable and prudent” fits with where I’m going. The Washington Driver Guide suggests that at speeds below 30 mph a following distance of two to three seconds might give you enough time to avoid an unexpected hazard, but the guide recommends a four second following distance.

In case you’re not familiar with how to measure following distance, let me explain. (If you already know it, you can skip to the next paragraph.) Watch when the rear of the vehicle in front of you passes a sign, pole or any other stationary point. Count the seconds it takes you to reach the same spot. When I was a kid playing football on the vacant lot in our neighborhood we had a five-Mississippi rushing rule, so I use Mississsippi’s, but if you prefer you can count one-thousand-one, one-thousand-two, and so on. You are following too closely if you pass the mark before you finish counting.

It takes human drivers, on average, 1.5 seconds to respond to an unexpected hazard while driving. That’s assuming the driver is paying attention. If you’re not even looking at the road (texting drivers I’m talking about you) it’ll take a lot longer. If the car in front of you slams on its brakes, by the time your eyes perceive the danger and send a message to your brain, your brain relays that message to your foot, and your foot applies pressure to your brake pedal, about 1.5 seconds have elapsed. So as long as you’re more than 1.5 seconds behind that vehicle you’re good, right?

That time is an average. We get an average from a bunch of results; some are more and some are less than the average. When you’re in a good mood, you’ve had plenty of sleep, and you’re focused on your driving your reaction time will be faster than if you’re grumpy, tired, stressed, and barely paying attention. Which scenario more closely describes your morning commute? A two second following distance starts sounding like a risky minimum and that four second recommendation starts looking “reasonable and prudent.”

Here’s the scary part: the deputy I interviewed is able to keep busy only stopping drivers that are following at less than one second behind another driver. The closest one I saw in my short time with him was a half-second. The people who enforce this law regularly have seen even closer, down near a quarter second.

If you are a driver that hasn’t given much thought to following distance, I challenge you to measure it on your next drive. You may be surprised to discover how close you are. A few seconds is a pretty good trade for keeping yourself and others safer on the road.




  1. THANK YOU, Doug Dahl for writing this article! People drive way too close to each other even in pouring rain. It’s scary. And if you, as a safe driver, stay further behind the person in front of you, oftentimes the person driving too close behind you will whip around you to fill in the space in front of you, as if to admonish you for leaving too much space. People need to know just how long it takes a two ton vehicle to stop when it’s going 60 mph. It’s definitely NOT 10 feet.

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