You’re driving down the road, and ahead of you, the two lanes merge into one. Do you join the crowd and patiently wait in line, or do you zoom to the front and merge at the last minute? And do you know which one is actually correct?

Well, legally, you can continue in either lane until you are told to actually leave the lane. This command is given with the “MERGE (left or right)” sign. All signs before that are simply warning you of conditions ahead.

When traffic is heavy and slow, it is actually much safer for motorists to remain in their current lane until the point where traffic can orderly take turns merging which is generally after the “MERGE” sign. Unfortunately, while the safer procedure is legal, it is not what has been taught.

A gentleman by the name of Tom Vanderbilt has actually written a book called Traffic, where he admits that after spending years frustrated, he became a late merger, and feels that life is better that way. He goes on to provide empirical data that it is indeed better, and safer, and in fact believes that this is what all that asphalt is for, after all.

Several countries, and US states, advocate something called “zippering” where cars weave in one by one, and essentially everyone late merges. But general consensus amongst the experts, is that piling up in a big long line to one side does nothing for the flow of traffic. Traffic studies by the Texas Transportation Institute and the Federal Highway Administration have shown that late merging promotes the full utilization of highway space and actually maximizes the flow of traffic. There’s a lot of sense, there, if you think about it: if the lane is available, why jump out of it and back up traffic instead?

But in the end, the reality is that it doesn’t matter what might be legal, or more efficient, most likely if you race to the front you’ll be deemed an a**hole by at least one person. I guess late merging isn’t for the faint of heart!