Amazing People, Amazing Innovations

 Aerial image of traffic in a roundabout.

Dimitra Michalaka is the definition of a busy college transportation engineering professor.

She teaches. She grades. She holds office hours. She attends faculty meetings. She oversees student research projects. She works on her own research projects. She publishes in academic journals. She reviews the research of other engineering faculty. She brainstorms how she could do it all better. She does it all again after lunch.

Dimitra Michalaka, The Citadel, Military College of South Carolina.

Click a button to watch an interview with Dimitra Michalaka:

But when you hear Dimitra talk about her work, you can sense that being so busy doesn’t bother her. In fact, you can tell that being bored isn’t even in Dimitra’s vocabulary. It’s not hard to see that she’s fascinated by her work, and passionate about its potential to improve our lives.

And lately, one subject in particular really takes the cake.

The roundabout intersection is one of Dimitra's areas of expertise. The roundabout is radically different than all other intersections. It’s also relatively new, at least to the United States. The amazing thing about the roundabout is its potential to save lives all over the country. Due to its circular shape and the details of its design, the roundabout intersection boasts 90% fewer fatalities and 75% fewer serious injuries than the traditional traffic intersection.1

Dimitra explained to Fast Forward a few of the key design features responsible for this huge safety boost.

For example, there are no left turns in a roundabout. Instead, cars drive in a loop until they reach their desired exit point going north, south, east, or west. This eliminates the possibility of passenger side collisions that happen at traditional intersections when a red-light-runner hits a left-turning vehicle.

Also, due to a roundabout’s shape, cars entering the loop are unlikely to collide with cars in the loop at a direct right angle, eliminating T-bone collisions. Instead of hitting the driver or passenger’s side head-on, impacts in a roundabout are more likely to affect a car’s front or rear quarter panels. Further, head-on collisions are not possible —unless someone is driving in the wrong direction. Roundabouts also force drivers to slow down dramatically, so that crashes that do occur are much less likely to be severe or fatal.

That’s what you call a marvel of transportation engineering.

Despite these benefits, roundabouts remain relatively uncommon in the United States for the time being. But they are becoming more popular, thanks in part to Dimitra.

City governments and planners are interested in roundabouts. But before building one instead of a traditional intersection, they want evidence that the roundabout will perform well in heavy traffic and won’t slow traffic down to the point of being impractical. Even Dimitra admits that some locations are poor candidates for the roundabout design. For example, when there is enough traffic that multiple lanes are required, or in areas known for major congestion, roundabouts might not be the best choice.

To determine whether an intersection is a candidate, Dimitra might be recruited by the city to conduct what’s called a feasibility study. She would gather data about the location of the proposed intersection, such as how much traffic it will see during peak hours. To do this, she would visit a similar intersection close by and literally count the cars (with the help of video cameras and graduate students of course) during rush hour. Back at her traffic lab, she'll create a lifelike computer simulation designed to look and behave exactly like the intersection in question would look and behave if it were built that very day. A computer program makes the simulation come to life and Dimitra can gather the evidence she needs to make a recommendation to the planning agency on whether a roundabout would be a wise investment.

Dimitra uses the driving simulator for other tasks, too. For example, she might recruit subjects to drive the simulator through a virtual roundabout to gather data on how much drivers actually reduce their speed or what causes the rare accident to occur. Dimitra says that the simulator is so realistic drivers often forget they are even in a laboratory. This is beneficial because it allows Dimitra to conduct experiments that mimic real life in the safety of a research lab—and for a lot less money.

Dimitra says being a college professor isn’t as glamorous—and definitely not as laid-back—as it’s cracked up to be. Her summers off are often spent conducting research, preparing her course curriculum for the fall semester, or publishing the findings of her research. But when she sees the results of her hard work paying off—whether it’s a roundabout being built, a paper being published, or a student graduating—she simply can’t image doing anything else.

1. Intersection Safety, Safety, Federal Highway Administration,

Aaron Mack
Fast Forward: Volume 3 Issue 2 - Highway