I drive a lot.
I’ve mentioned this in previous blog posts but I feel the need to mention it again. I drive a lot.
Driving a lot means that I get to experience certain driver behaviors more regularly than many others. Almost daily, I’ll encounter the people who drive in the left lane without passing. I’ll see the people who drive for miles and miles with a blinking turn signal. I’ll also see those people who weave in and out of traffic and try to gain whatever minuscule advantage they can.
Across all of the different driver behaviors, there is one that I have taken on as my own personal mission: the zipper merge. If you’re not familiar with the term, the zipper merge relates to lane closings on a highway. You probably know the situation. You’re driving along and you see a sign that says, “Right lane closed in two miles.” This usually starts the countdown. Another mile down the road, you’ll see another sign that says, “Right lane closed in one mile.” In case you missed the previous two signs, you’ll be alerted again a half-mile, quarter mile and 1000 feet before the lane closure. For obvious safety reasons, departments of transportation are excessively vigilant about communicating pending lane closures.
The challenge, however, is what you as the driver do as you encounter the numerous signs. For many drivers, almost inexplicably, they choose to merge when they see the first sign. Maybe they don’t want to be rude and wait until the last minute to merge. Or maybe they were taught to merge when they see the first sign. Or maybe they just follow the actions of the majority of the other drivers on the road. Regardless of their rationale, they merge early, usually a mile or more before the lane closure.
But, here’s the bigger challenge. Research shows that traffic will move more quickly if drivers wait until the merge point. Many departments of transportation officially recommend the “zipper merge.” In practice, this means drivers should wait until the lane closure and take turns merging. The name actually comes from how the merging traffic would look like the teeth of a zipper coming together if viewed from above. In a study conducted by the Minnesota Department of Transportation, they found that the practice reduces the overall length of a backup by 40-50%. Research also suggests the practice makes merging safer for everyone.
I’ve been advocate of the zipper merge for a while. For some reason, however, the practice is viewed as rude, aggressive and ineffective. Despite numerous states advocating for the zipper merge as a driving practice, many people still merge early and cast an angry eye at those of us who wait until the lane closure to merge. I’ve gotten in my fair share of social media debates with friends and colleagues who look down on us zipper mergers. I’ve also received quite a few offensive hand gestures, honks and curses from neighboring drivers who chose to merge early.
This brings me to the larger point of this post. The zipper merge is but one example of how data and evidence don’t always align with practice. Despite research showing it to be safer and more efficient, the zipper merge is not widely used. But that’s the same result for a host of other evidence-based practices. As humans, we don’t always do the “right” thing.
Bringing this back to teaching and learning, we have to be sure that the practices we choose align with data and evidence. Give prompt feedback for growth. Incorporate active learning instead of lecturing. Provide explicit learning objectives and outline clear expectations. While I don’t know if any of these rise to the cultural dissonance created by the “zipper merge,” there’s a lot of evidence demonstrating the efficacy of these teaching practices. We just need to get instructors to merge into the “right” lane.