TWM Contributor: Nick Correnti, PE Transportation Project Manager

Infrastructure Enhancements to Missouri Route 100 (Manchester Road)

Rehabilitation of a Major Arterial Roadway

TWM’s transportation group was recently involved in a multi-phase project that involved robust infrastructure enhancements along the historical Missouri Route 100 in St. Louis County. Missouri Route 100 is 121 miles long in total and spans five counties. It begins at U.S. Route 50 in Linn, Missouri and concludes at South Broadway in downtown St. Louis at the I-55 overpass. Much of the road between St. Louis and Gray Summit was part of the original U.S. Route 66. Most of Route 100, as it exists today, is part of the Lewis and Clark National Historic Trail. Known locally as Manchester Road, Route 100 is a major arterial roadway in the St. Louis Metropolitan Area. St. Louis County needed 4.7 miles of rehabilitation from N. Kirkwood Road to Big Bend Road. TWM was pleased to be selected to team up with the Missouri Department of Transportation (MoDOT) to resolve a variety of critical traffic and pedestrian issues along this corridor.

Conceptual stripmap

Design Elements | The project required key design elements including pavement resurfacing and improved drainage, pavement markings, pedestrian facility analysis and ADA improvements, bridge replacement, traffic signal upgrades and replacements, structural design of an impressive pedestrian underpass and adjacent retaining walls, and streetscape elements. Additionally, sidewalks were upgraded to current ADA standards, bicycle facilities were added in key locations to provide better connectivity for non-motorized transportation users.

Existing roadway safety was reviewed along the corridor, and features such as midblock crossings equipped with Rectangular Rapid Flashing Beacons (RRFB) were placed at strategic points to provide added visibility for pedestrians crossing this 4-lane roadway in locations not near signalized intersections. It also included a grade separation for a trail extension intended to keep bicyclists and pedestrians safe from traffic as they cross seamlessly underneath Manchester Road.

During construction in Kirkwood

Collaboration | TWM’s extensive coordination with local municipalities and adjacent agencies included working with St. Louis County, Metro Transit/Bi-State Development (Metro), Metropolitan St. Louis Sewer District (MSD), Great Rivers Greenway (GRG), and numerous utility companies. As the prime consultant on this complex project, we managed client coordination, conducted progress meetings, and held internal team meetings as needed. We interacted directly with MSD on everything related to water quality and stormwater detention and Metro on finalizing bus stop locations and coordinating improvements on MoDOT right-of-way throughout the life of this project. Our scope varied throughout the process, from stakeholder coordination, planning and traffic studies, surveying and staking, and engineering design to construction support, and public engagement. We provided quality control and quality assurance in all procedures and project deliverables to ensure they achieved a high standard.

Completed construction in Kirkwood

Tom Blair, MoDOT St. Louis District Engineer, said, “At each step, TWM was responsive and thorough, always quick to consider our needs and the impact of the public.”

Beautification | In addition to roadway and pedestrian upgrades, TWM was responsible for helping to create a vision for the newly rehabbed corridor from Kirkwood to Maplewood. Most notably, the team led the design efforts to implement the City of Brentwood’s vision of a renewed Manchester Road through the city limits as part of the Brentwood Bound project. The goal of Brentwood Bound was to overcome the long-term challenges of flooding and aged infrastructure to create an opportunity for park and recreational spaces to be enjoyed by Brentwood residents.


Key improvements included an arched pedestrian underpass for Rogers Parkway Trail in Brentwood (photos above), realigning Mary Avenue and Dorothy Avenue, raising Manchester Road to accommodate the underpass, adding 1,000’ of shared-use path to connect Rogers Parkway to a future GRG Deer Creek Connector path, and beautifying the corridor with landscaping and wayfinding/branding signs. Two shared-use paths were designed to maximize non-motorized mobility through the corridor – a 1.25 mile-long 10’ wide shared-use path on the south side on Route 100 throughout the city limits of Brentwood running east-west, and a north-south 12’ wide shared-use path connecting Rogers Parkway to Deer Creek Greenway via the newly constructed pedestrian underpass under Route 100.

Public Support | A robust public engagement campaign helped to garner support for the project along the way, from scheduling full-scale open house style public meetings to one-on-one discussions with local individuals and stakeholders. Other planned capital improvement projects for outside agencies were bundled into this project to allow construction work to happen just once, further reducing the impact on the public and saving both time and precious tax dollars. Additional funding for beautification along the road was provided by the Cities of Brentwood and Kirkwood to help give the corridor a cohesive identity for residents to be proud of that included pedestrian scale lighting, stamped and colored concrete, banner sign poles, and a vertical gateway monument to signify the city limits of Kirkwood.

Utility Coordination | The project delivery involved coordination with numerous utilities, public government and non-government agencies, local transit authority, a railroad, and six different municipalities. In doing so, it overcame several challenges, such as placing modernized pedestrian infrastructure into a narrow well-developed corridor filled with a robust network of utilities, buildings adjacent to sidewalks, difficulties brought on by the Covid-19 pandemic, negotiations for right-of-way and easement rights on over 200 individual properties, and even flooding from historic rainfall events during construction. By incorporating LiDAR technology early on and design for innovative construction methods, the project was able to sidestep conflicts with many utilities and deliver the development with a reduced impact to the traveling public. Through the tireless effort of MoDOT, the design team, and coordination with many partners and local stakeholders, the rehabilitation of Route 100 is a project that will leave a long-lasting positive mark on the community for years to come.

About TWM’s Transportation Services
TWM’s transportation engineers provide a full range of design and construction observation services, bringing our clients established relationships with reviewing agencies such as the DOT, DNR/NRC, and USACE. Our team has designed hundreds of miles of state highways, local roads and bridges, several roundabouts, thousands of curb ramps, bike trails and sidewalks, and multi-modal enhancements. They also assist municipalities with ADA planning and pavement management programs, in addition to completing traffic studies, coordinating public engagement meetings, negotiating purchases of land, and acquiring necessary permits.

Read more about our Transportation services.