The new I-70 river bridge: Not the best project that could be

The new Mississippi River bridge currently being built north of downtown St. Louis is supposed to relieve congestion on the PSB. However, for many reasons, it may have not been the best project that could have been pursued. Consider:

* Westbound I-70 traffic already has a non-stop alternative to the PSB via the MLK Bridge. Eastbound I-70 traffic only has to face one light before entering the MLK Bridge. Using the MLK Bridge for through movements to WB I-44 or SB I-55 requires a long trip through downtown to return to the interstate. EB I-44 or NB I-55 through movements have a slightly easier time accessing the MLK - except when special events close Memorial Drive - but it still requires a mile long drive through downtown. This route also includes a sometimes difficult right turn onto Convention Plaza to access the MLK Bridge.

* The I-55 PSB ramps seem to back up regularly outside of rush hour, while the I-70 ramps are almost always free flowing outside of rush hour, excluding ball games.

* Sure, MoDOT says they will fix the access issues if a companion bridge is built in the future. However, there is no guarantee that the companion bridge will ever be built. In addition, what happens should the PSB become unusable for a long period due to a barge collision, severe hazmat accident, or increasing maintenance issues?

Driving Distances
For traffic heading to I-70 or I-55 beyond Troy:

• From the I-70/I-270 interchange:

- 30.8 miles via I-270
- 38.9 miles via the PSB
- 37.23 via the new bridge (initial build)

• From the I-55/I-270/I-255 interchange:

- 34.7 miles via I-255
- 32.7 miles via the PSB
- 34.3 miles via the new bridge had access been provided in the initial phase

• From the I-44/I-270 interchange:

- 40.5 miles via I-270 and I-255
- 35.4 miles via the PSB
- 45.1 miles via I-270
- 37.0 miles via the new bridge had access been provided in the initial phase

For traffic heading to I-64 east of St. Louis, using the point where the I-255 ramps merge onto I-64 as the eastern end:

• From I-44 at I-270:

- 26.5 miles via I-270 and I-255
- 23.2 miles via the PSB
- 24.66 via the new bridge had access been provided in the initial phase

• From I-55 at the I-255/I-270 interchange:

- 20.6 miles via I-255
- 21.9 miles via the PSB
- 23.36 miles via the new bridge had access been provided in the initial phase

• From the I-70/I-64/US 61 interchange at Wentzville:

- 48.2 miles via I-64 and the PSB
- 47.2 miles via I-70 and the PSB
- 58.5 miles via I-64, I-270 south, and I-255
- 56.3 miles via I-70, I-270 east, and I-255
- 52.7 miles via I-70, I-170, I-64 and the PSB
- 45.45 miles via I-70 and the new bridge

What Could Be Done
Since it is too late now to abort the project and instead look again at a new bridge south of the PSB, there are a couple of changes to the new bridge project that could make this project much more useful to all.

* Add a new WB I-70 exit and a new EB I-70 entrance between Memorial Drive and the new bridge. While not an ideal solution, this would at least make it easier to access the new bridge from the south without as much time sitting at stoplights. The best location would be at Cass Avenue, but new ramps here would require closing the existing EB exit/WB entrance to/from Broadway or using a more costly braided design.

* Replace the current entrance to WB I-70 south of St. Louis Avenue with a new WB exit. This would at least allow a somewhat indirect U-turn option that might aid in any closure of the PSB

* Simply add the ramps to the south. Supposedly adding those ramps now would be incompatible with a future companion span, but the current design is not entirely compatible with the companion either. The connection between EB I-70 and the first bridge will be unneeded and require modification and removal, so why not modify it in the initial build to allow a more useful product?

The fun begins on I-270

MoDOT will soon begin preparations for bridge work on I-270 for the bridges over Rott Road and I-44:


It will be interesting to see how this project impacts traffic.

More work on I-270 Chain of Rocks Bridges, commentary on the proposed replacement

IDOT begins more repairs on both the Chain of Rocks Canal Bridges and the main channel bridge on I-270 today.

Commentary/rants
It is because of the frequency of this work that IDOT is currently studying a replacement of the canal bridges. However, based on the presentation at the public meeting for the canal bridge replacement, the replacement will be partially obsolete as soon as it is built. There will only be four foot shoulders on the eastern end of the new bridge, and should I-270 ever get its much needed widening to six lanes between IL 111 and Lilac Avenue, there will be four foot shoulders for the whole bridge. The widened route may also have issues with the merge for IL 3 southbound traffic onto westbound I-270. If IDOT is going to undertake a total replacement for the canal bridges, they should build the new one right with a full right hand shoulder.

Design changes for I-270 interchange with Page Avenue (MO 364/Route D)

MoDOT is announcing a major design change for the interchange between I-270 and Page Avenue (MO 364/Rte D). The NB I-270 to WB MO 364 ramp will be changed from a semi-direct flyover (like the ones at the I-255/I-270/I-55 cloverstack) to a more looping, turbine ramp with separate bridges for crossing the mainlines of Page Avenue and MO 364 like the NB I-465 to WB I-70 ramp on the west side of Indianapolis). The new design also changes access from WB Page to Bennington Place; instead of a braided design, traffic from WB Page will have to weave with traffic from SB I-270 desiring to access WB Page. The official site for the I-270 projects at Page and Dorset has a map showing the new deisgn while the older project site still has a map with the old design.

The new design for this interchange will lessen impacts on I-270 and Page Avenue in the short term - pier construction for the original flyover design would probably require closing the left lanes on both routes - and saves more than $1.4 million. Long term, however, I have concerns that the new design will repeat the weaving failures experienced on the WB I-44 ramp to I-270.

In addition, the future second phase project for this interchange has been changed. The original second phase was to add a flyover for the SB to EB movement. Now the future second phase will be adding a similar turbine ramp for the WB to SB movement. As seen in the animation MoDOT has posted, this design requires construction an underpass to get this ramp under MO 364. Such a design will require a temporary shoo-fly for MO 364 to enable this bridge to be constructed. Without more design information, it is my opinion that an overpass for the new ramp would be better. In addition, this new design is not weave free; EB MO 364 traffic wanting to access NB I-270 will have weave with SB I-270 traffic wanting access to EB Route D. This design is less safe, and may have congestion issues depending upon future volumes. Unless there is a hope to eventually remove another loop from this interchange (in a perfect world with more funding, I'd make this interchange loop free), the second phase should stick with replacing the SB to EB loop.

(Disclaimer for the heck of it: I have no current affiliation with MoDOT or anyone involved with this project.)