It’s Time to Listen to MoDOT: Poplar Street Bridge Access to I-70 Needs to Disappear

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map_broad_view2In 2001, after many years of study, public meetings, regional discussion, and E/W Gateway approval, the DOT’s received a Record of Decision (ROD) from the Federal Highway Administration to move forward with the New River Bridge project. This ROD would build a New I-70 River Bridge about one mile north of the Poplar Street Bridge. After I-70 was relocated to the new bridge, the PSB would only carry I-55 and I-64 traffic. As a part of that approved plan, the MO interchange on the PSB was to be rebuilt to eliminate the I-70 connection and build dual I-55 ramps in its place.

This is how MoDOT describes the rather mundane plan to reconfigure Interstate highway traffic in and around downtown St. Louis (full project description and slideshow below). Of course when you're talking about changing a highway, affecting someone's driving habits, the conversation quickly becomes anything but mundane. One might be led to believe that the right driving one's car from point A to point B via a particular route had been enshrined in our Constitution.

The plan since before 2001 has been to "eliminate the I-70 connection and build dual I-55 ramps" at the PSB. This, according to MoDOT would very nearly eliminate traffic back-ups on the PSB and connecting ramps. The redundant I-70 ramps must be removed to make room for dual I-55 ramps, the key to eliminated dangerous traffic conditions. And so MoDOT was apparently surprised in June 2011 when East-West Gateway effectively reinstated the I-70 ramps due to "a belief that removing the I-70 ramps from the PSB would negatively affect the Sauget area in St. Clair County". According to MoDOT, about 3 percent of PSB traffic today travels to and from the Sauget area.


{the MoDOT plan as it stood in May 2011}

And so MoDOT went back to work. The new challenge is to build the needed dual I-55 ramps while maintaining the unecessary I-70 connection. MoDOT found that the west bound ramp off the PSB and into the current I-70 has a negative safety effect, but could be maintained by adding a lane to the depressed section of Interstate from the PSB to the CityArchRiver planned exits at Washington Avenue (again, necessary only if Memorial Drive is closed). At this point, there are so many negative externalities to closing Memorial Drive, one must question the idea regardless of any suggested benefit. MoDOT goes on to say, "Although it is questionable whether or not this ramp is beneficial due to the fact that very little traffic is expected to use it, MoDOT is able and willing to replace the PSB ramp to West bound I-70 ( I-44)." Looking at east bound traffic, MoDOT found, "retaining the EB I-70 (I-44) ramp to the PSB is simply not feasible, nor is it safe."

To be clear, the misguided and unbalanced concern for 3% of PSB traffic combined with the blind devotion by CityArchRiver to close Memorial Drive is dictating millions of dollars in additional infrastructure investment, years of unnecessary construction and increased safety concerns at our most congested highway interchagne. In the end, 3% of PSB traffic might retain a westbound ramp from the PSB, but not an east bound. If not both, why either? In this instance, the MoDOT preferred alternative costs less, relieves more congestion and results in safer roadways. Concerns regarding access to and from St. Claire County, IL was recently covered by the Belleville News Democrat. Judging by reader comments to that story, metro east residents are overwhelming more concerned with eliminating backups on the PSB than with access for 3% to Sauget.


{the MoDOT plan as of June 2011, showing restored access to widened depressed lanes to remediate closing of Memorial Drive by CityArchRiver}

There is simply no reason to maintain access from the PSB to the depressed lanes. Highway infrastructure at the point creates a barrier between the city and Arch grounds 13 lanes wide. Currently, the first exit from those lanes is nearly two miles north of the PSB and north of the landing for the new Mississippi River Bridge. This access is for through traffic, not those entering downtown St. Louis.  The preferred option from the CityArchRiver project would rebuild and reverse highway ramps to provide a northbound exit to Washington Avenue. This is only needed because the group is seeking to close several blocks of Memorial Drive. This is the circular logic that passes for planning in St. Louis.

MoDOT serves clients. They also prioritize traffic flow at the exclusion of other considerations such as livability, the environment, neighborhoods, business development, walkability and local access. Those concerns should be expressed by local and regional planning authorities, residents and other stakeholders. With some irony, the focus on traffic throughput at the PSB could improve all of the above by eliminating recurring congestion and facilitating the reconnection of the city to the Arch and river.


{the MoDOT PSB interchange plan as it currently exists – green ramps rebuilt and red eliminated}

The narrative here is simple, if MoDOT engineers could rebuild the PSB west side interchange as they would like as part of the new Mississippi River Bridge project, the problematic connections between I-55/I-44 and the PSB would be largely solved. Even MoDOT knows that the purpose of Interstate highways is to funnel traffic around (and maybe through) cities and not to create access to neighborhoods. The PSB reconfiguration is necessary to take advantage of the $1.6B total project investment. In fact, the new bridge makes solving the problems on the PSB finally possible. It also makes it possible to consider converting what will become the former I-70 into an urban boulevard.

How should real access for more than 95% of the motorists encountering the west side PSB interchange be achieved? Listen to MoDOT. Eliminate the east bound PSB ramp from Memorial Drive and the I-70 depressed lanes, eliminate access to the north bound current I-70 depressed lanes from the PSB. Retain Memorial Drive as-is and eliminate the need for new highway ramps. This would not only offer by far the best solution for existing congestion, it would further lessen the amount of traffic on existing I-70 between the PSB and new Mississippi River Bridge (both depressed and elevated lanes). This would, in turn, best set the stage for this section of highway to be converted to an urban boulevard.


{the PSB interchange as it should be – rebuild green ramps, eliminate red and yellow – with possibility to retain yellow to a maintained Memorial Drive}
MoDOT Poplar Street Bridge Project

Full MoDOT PSB interchange project description:

In the early 1990’s the St. Louis Regional Leaders were concerned about the traffic issues in downtown St. Louis. In 1992, MoDOT and IDOT embarked on an environmental study (EIS) to look for solutions. The resulting EIS very clearly spelled out that the problem was the Poplar Street Bridge (PSB). The PSB is one of only two bridges in the nation that carry three interstates (I-70, I-55, I-64) across a river. The PSB was built in the 1960’s and was never meant to carry the amount of traffic it does today. It was designed to 1960 standards and for today’s traffic, the ramp radii are too sharp, and there is not enough room between the exits and entrances thus causing major weaving issues. This is the reason the accident rate at this location is three times greater than a normal interchange and why trucks periodically overturn on the ramps. The study recommended building a new river bridge to the north and making substantial safety changes to the PSB.

In 2001, after many years of study, public meetings, regional discussion, and E/W Gateway approval, the DOT’s received a Record of Decision (ROD) from FHWA to move forward with the New River Bridge project. This ROD would build a New I-70 River Bridge about one mile north of the PSB. After I-70 was relocated to the new bridge, the PSB would only carry I-55 and I-64 traffic. As a part of that approved plan, the MO interchange on the PSB was to be rebuilt to eliminate the I-70 connection and build dual I-55 ramps in its place.

PSB ramps

In the mid 2000’s, when both states realized that neither state could afford the nearly $2 billion dollar New River Bridge project, the EIS was revised to build the project in functional phases. The first phase, which is the New 4 lane MRB, is currently under construction. As this project is about halfway complete, MoDOT had placed the second phase of the project, the replacement of the PSB MO interchange ramps, on the Regional Transportation Improvement Project (TIP) for a summer of 2013 letting. The concept was to have the project on the TIP, funding in place, and plans prepared so that as soon as the MRB is open to traffic in early 2014, the construction of the PSB MO Interchange ramp project could start.

By removing the redundant I-70 ramps, MoDOT could make room for dual I-55 ramps that would greatly enhance safety issues on the PSB and almost eliminate the congestion on all the interstates in the area.

On June 29, 2011 at the E/W Gateway Board Meeting, E/W Gateway removed a TIP project involving the PSB Mo Interchange from the 2012-2015 TIP.

2015 AM Congestion

After the meeting, the department worked to determine why that project was removed from the TIP. It was determined that there was a belief that removing the I-70 ramps from the PSB would negatively affect the Sauget area in St. Clair County. Currently, about 3 percent of the traffic that uses the PSB travels to and from the Sauget area. MoDOT was asked to review options to replacing the I-70 ramps and to review findings from the ROD.

With this request, MoDOT has been reviewing all viable options of replacing the I-70 ramps to the PSB while maintaining dual I-55 ramps.

MoDOT first analyzed the WB ramp from the PSB to NB I-70 (newly named I-44). The replacement of this ramp, along with changes being made to the depressed lanes due to the City Arch River project, can be accommodated safely because an auxiliary lane can be added in the depressed lanes from the PSB ramp to the newly planned exit ramp at Washington Ave. MoDOT has also completed a traffic analysis of the affect of adding this ramp. The ramp does have a negative effect on the I-44 NB lanes coming from the south by lowering the level of service (LOS) from a C to a D in am rush-hour. Although it is questionable whether or not this ramp is beneficial due to the fact that very little traffic is expected to use it, MoDOT is able and willing to replace the PSB ramp to West bound I-70 ( I-44).

2015 PM Congestion

MoDOT then looked at adding the EB I-70 (I-44) ramp from the depressed lanes to EB PSB. This ramp has many safety andcongestion issues that make it undesirable to build. MoDOT has completed conceptual engineering on four different options to build this ramp. The traffic analysis done for all of these options shows that this ramp will cause major traffic concerns, lowering interstate congestion from a LOS C to an F at various locations. All of these options also include a very sharp ramp radius, (25 mph) which is sharper than the ramps that exist today and causes safety concerns involving truck rollovers. Several of the options called for very short tapered ramp entrances that are twice as likely to cause accidents as the typical parallel ramp entrances. Some of them have poor sight distance, entrance and exit ramps too close together, and left hand exits and entrances, all which are major safety concerns. Some of them involve ramp grades that are simply unacceptable and all lower the planned vertical clearance over the interstate from 16.5’ to 15’ or below. MoDOT determined that adding this additional ramp would be introducing safety and congestion issues that would contradict the intent of the improvements to solve those very issues. Access will still exist, with minor inconvenience, for the small amount of traffic that is generated from the area of concern via the new MRB or via I-170 to I-64. Building dual ramps between the PSB and I-55 while retaining the EB I-70 (I-44) ramp to the PSB is simply not feasible, nor is it safe.

PSB ramp condition

The condition of PSB ramps are beyond their useful life and are literally falling apart. They are rated a 3 out of 10, which means they are one step away from being closed to traffic. The do-nothing option will require MoDOT to consistently be working on the ramps just to maintain them. Eventually they will have to be closed due to safety reasons. The cost to rebuild them in place will be over $40 million- that money will have to come from the region.

The do-nothing approach, or replacing the ramps as they exist today, would undermine the $700 million dollar investment made in the MRB. Without making the changes as planned to the PSB, traffic congestion on the interstates in downtown St. Louis (I-64, I-55 and I-44) will still be at a crawl during rush hour.

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