When I-69 Finish Line opened in August 2024, INDOT made a bit of little-known history. Indiana now is home to one of only three tri-concurrent interstate sections in the United States.
A concurrency in a road network is an instance of one physical roadway bearing two or more different route numbers. Such concurrencies involving interstates and highways are common in both Indiana and the country. However, before last August, there were only two triple concurrencies involving only interstates. In Wisconsin, I-39, I-90, and I-94 run together north from Madison for approximately 50 miles. Also, I-41, I-43, and I-894 are concurrent for a short distance in Milwaukee.
Now Indiana has joined the mix. I-69, I-74, and I-465 run together around a portion of I-465 on the south and east sides of Indianapolis. This became the case when the I-69/I-465 interchange on the south side of Indianapolis opened in August 2024. The three interstates are joined from the south side to where I-74 breaks off on the southeast side. Later, I-69 breaks off on the northeast side.
Indiana, and the nation, has many concurrencies beyond interstates. One reason is because the Federal Highway Administration mandates that U.S. routes must be contiguous. When a U.S. route enters a state, it can’t have a distance break. Hence, they become part of route concurrencies, also called travel-overs.
A prime example is in Indianapolis, where the nation’s second-highest concurrency is located.
In the one-mile section of I-465 between Exits 46 and 47 on the southeast side of Indianapolis, there are nine designations, albeit unsigned: I-465, I-69, U.S. 31, U.S. 36, U.S. 40, U.S. 52, U.S. 421, State Road 37, and State Road 67. Only a short segment of the George State Route 10 Loop in Athens, Ga., has more. That section contains 10 designations.
