While sitting at a stoplight, have you ever thought, “There has to be a better way?” I don’t think I have, but clearly a few traffic engineers have decided the normal intersection design just doesn’t deliver the kick they’re looking for. They wanted something more. Something intense. Something like…


The Diverging Diamond Interchange

I have quite a bit of experience with DDIs because the first two ever constructed were built right here in Springfield, MO.

Diverging Diamond Interchange

This is designed for highway exits onto major roads. You’ve probably gathered from the picture that the lanes of traffic cross over each other with stoplights at the two crossovers. That’s right: you’re driving on the left side of the road. Everyone gets to feel British for a few seconds.

There are several advantages to this over a typical highway exit. For one, people getting onto the highway don’t have to wait whether they’re making a right or left, eliminating left-turn lanes. Additionally, all foot traffic goes to the middle, which means there is only need for one sidewalk. This maximizes the amount of space for lanes in both directions.

My personal opinion is that this helps keep traffic flowing smoothly and removes things that lead to gridlock-causing bottlenecks (like people waiting to take a left onto the highway).

The Michigan Left

Sharing the term for Democrats from Michigan, this oddball method of turning left involves going straight through an intersection, THEN getting into a turn lane, making a U turn into a special lane, and making a right turn. Two wrongs don’t make a right, but a U-turn and a right do make a left. Just like I learned in Sunday school!

Michigan Left

This one is easy enough to get by looking at the picture, though I’d have to see the data to decide whether it actually improves throughput while retaining safety. Unlike the DDI, I don’t have personal experience with this one.

However, there are some designs that you can’t help but look at and think that creative traffic engineer was getting his ideas from an LSD trip. Actually, just one:

The Continuous-flow Intersection

Continuous Flow Interchange

Deep in the bowls of the lifeless mountains in northern Mexico, there arose a cult so evil that Hell itself spat them out. From this boiling cesspool of unrighteousness arose a leader skilled in all things profane, and he vowed it his life’s work to create the Continuous-flow Intersection. Francisco Mier, known as Beelzebub Mier to his friends, possessed several members of the México Departamento de Transporte to build one of these, after which they took off like wildfire, or Hellfire, whichever burns faster in the local climate.

There have been only 37 implimented so far, but don’t be fooled: this is merely part of their plan. 37, after all, is just 666 divided by 18, the number of years until their prophesied doomsday.


Like what I’ve written? Let me know in the comments below. Also, check out some less extreme alternatives to normal intersections like the Jughandle, the Superstreet, and perhaps least logical of all, the Hook Turn.

edit 7/14/12: I realized just now that somehow the image for the Continous-flow Intersection didn’t get inserted into the post. It’s on now. Definitely helps drive my point home.