The graphic we published on Sunday showing the traffic patterns for the interchange of U.S. 231 with the Shelbyville bypass drew a sharp response from some readers, pointing out that some people will have to make left turns onto or off of 231, and predicting that the intersection will be dangerous as a result.
Some good points have been raised, and I think there are some legitimate concerns, but I did want to point out one small factor in the line of being devil's advocate.
The vehicles using the bypass as a bypass -- going, in the vaguest possible terms, from Murfreesboro to Tullahoma or from Tullahoma to Murfreesboro -- will only have to make right turns at the 231 intersection. (You can also substitute "industries in the eastern part of Shelbyville" for "Tullahoma" in that sentence.) The Tullahoma-to-Murfreesboro traffic will turn right from the exit ramp onto 231. The Murfreesboro-to-Tullahoma traffic will turn right from 231 onto the entrance ramp.
Most of the left turns across 231 will be made by those using the bypass for local traffic rather than as a bypass. That will still be a substantial number of drivers, but perhaps TDOT was assuming it would be less than the number who are using the bypass as a bypass. I haven't spoken to anyone from TDOT about this; it's just speculation on my part.
As I said, I understand the criticism of the interchange design, and I think the critics may have a point. I just thought people were missing that nuance of the conversation.