Traffic Interchange Makes Good Sense for State Governments in Era of Tight Road Budgets

Here’s one of those instances in which what I do hits close to home. In the latest issue of Capitol Ideas and a recent blog post, I wrote about how a number of states are following the lead of Missouri in employing a relatively new type of traffic interchange called the diverging diamond or double crossover diamond interchange to improve safety and reduce congestion. The interchanges can be built in less time and at a lower cost than other types of interchanges. Now, it appears I may soon get to see firsthand how the diamond works. The Lexington Herald-Leader reports that Kentucky transportation officials announced this week that they plan to reconfigure a Lexington intersection that is part of my daily commute using the diamond model.

The area around the intersection of Harrodsburg Road and New Circle Road is traveled by more than 35,000 vehicles each day and has the highest crash rate of any major artery in the city. Planners believe reconfiguring the intersection will reduce delays, increase capacity and decrease the number of crashes. The diamond configuration will eliminate left turns that require drivers to cross in front of oncoming traffic. It will require drivers to instead cross over and drive on the left side of the road to access the on-ramps to New Circle Road, one of the city’s major beltways.

State officials say the project will cost an estimated $5.5 million because it will continue to make use of the existing infrastructure rather than requiring complete reconstruction of the intersection, which could run in the range of $15 million to $20 million.

Work on the new interchange is expected to begin in June and be entirely complete by November. Best of all for my daily commute, much of the work will be done on nights and weekends.

The project will be the first double crossover diamond in Kentucky, with two more being designed for Interstate 75 in the northern part of the state. Five of the diamond interchanges are currently in operation around the country.

But at least a few Lexingtonians appear to be skeptical about whether the new interchange will actually improve things. In a letter to the editor Thursday, one reader recalled when the city put in a roundabout a few years ago that seemed to cause mass confusion.

“I am not looking forward to what seems like something much harder to figure out,” the reader wrote. “Driving on the left? Crossover traffic? I drive this area every day, at all times in lots of traffic. The snarl this could cause boggles the mind. I do hope I’m wrong.”

State officials and city planners hope and believe that reader will be proven wrong. Based on the success of the diamond in Missouri and elsewhere, there’s no reason to believe it can’t be successful in my hometown as well. The potential benefits to state governments in these times of tight road budgets seem hard to deny.