More than 100 people took part in virtual meetings regarding possible improvements to I-55 in southern Jefferson County, according to the Missouri Department of Transportation, which held the meetings on Jan. 19-20, the agency reported.
According to the MoDOT website, the project is intended to improve safety along the 7.5-mile stretch of I-55 from the Hwy. Z interchange at Pevely to the Hwy. 67 interchange south of Festus, which has a higher crash rate than statewide averages. In addition, regular traffic, combined with recreational traffic, along the I-55 corridor leads to periodic traffic congestion, MoDOT reported.
The start of construction on the improvement project is not expected to begin for at least a couple of years as information is gathered and improvements are designed, according to MoDOT officials.
During the meetings held last month, the department displayed two conceptual design alternatives for potential upgrades to the stretch of I-55.
Jenn Becker, a MoDOT transportation project manager, said both designs recommend adding a third lane in both directions along that stretch, as well as options for new interchanges at Pevely, Herculaneum, Hwy. A in Festus and Hwy. 67. There also could be a new bridge across I-55 between Hwy. A and Hwy. 67.
Below are the interchange alternatives as described by Becker:
■ Pevely: Alternative 1 – Relocate Weier Road east of its current location to line up roughly across from the current I-55 southbound off-ramp, install signals as part of the Hwy. Z interchange and install a roundabout. Alternative 2 – Relocate Weier Road west of its current location to line up across from the truck stop entrance. The intersection would not have a signal, but would allow drivers on both Weier Road and the entrance to see better. It also puts more space between Weier Road and the southbound I-55 ramps, which would allow room for vehicles to change lanes to make left turns. The I-55 southbound ramp would be extended to allow more space to accelerate onto the highway.
■ Herculaneum: Alternative 1 – Install roundabouts at the ends of the interchange ramps. Alternative 2 – Convert the interchange to a single-point urban interchange. The two signals at the interchange would be changed to one signalized interchange. The design is similar to the existing configuration at Hwy. A and I-55.
■ Festus: Alternative 1 – Convert to a diverging diamond interchange, which would create two signals on either side of the interchange, but would only have east and west traffic on Hwy. A crossing each other. The left-turn movements on and off the interstate would then not conflict with traffic from other directions. Alternative 2 – Modify the existing single-point urban interchange, which would consist of minor geometric improvements to the existing right turns from Hwy. A onto the ramps to better encourage the intended yielding movements to improve safety.
■ I-55 and Hwy. 67: Alternative 1 – Convert to a diverging diamond interchange like the Hwy. A interchange described above, with two signals on either side of the interchange where the two directions of Hwy. 67 would cross each other. Hwy. 67 also would be relocated to go over I-55. Alternative 2 – traffic from northbound Hwy. 67 would exit before I-55 and circle around the interchange on a much larger radius curve so vehicles could enter I-55 without going through the signal. There would be two signals on Hwy. 67 on either side of I-55 to serve all the other left- and right-turning movements at the interchange.
■ Related to the I-55 improvement project, MoDOT also would change the Hwy. 67 and Hwy. CC interchange. Alternative 1 – Convert it to a grade-separate intersection in which Hwy. 67 would be lowered under Hwy. CC to eliminate the hill between Hwy. CC and I-55. Hwy. 67 median crossings would be closed and drivers would make U-turns at the new interchange or a signal at the revised I-55-Hwy. 67 interchange. Alternative 2 – Add a third lane in each direction from west of Hwy. CC to I-55, while closing median crossings in the same stretch.
Becker said MoDOT solicited feedback from those who participated in the January meetings, and as of Tuesday was still compiling the comments the agency received.
For more information, visit MoDOT.org/I-55-Corridor-Improvements.