Howard R. Green Company (HR Green) is the lead consultant on this extensive study for the improvement of Interstate 29 from the Sioux Gateway Airport Interchange north to the South Dakota border. The project corridor is 10 miles long and includes six service interchanges and a system interchange. Total cost of all improvements may eventually exceed $110 million. HR Green’s role includes overall management of the consultant team and leadership of conceptual design, public involvement, environmental assessment and traffic analysis. The project approach has closely followed the Iowa DOT’s “CAN-DO” process, coordinating NEPA studies, permitting, and design and providing a concurrence point process for coordination with resource agencies.

HR Green’s initial conceptual design involved several concepts in the downtown or central section of the corridor, three concepts for the southern section, and two concepts for the northern section. Concepts were screened for environmental impacts, construction costs, traffic operations, right of way impacts, and constructability. Refining the most feasible concepts involves developing conceptual profiles, bridge types and lengths, and roadway modeling for approximate earthwork quantities and footprint. Refined concepts were evaluated for environmental impacts, traffic impacts, right-of-way impacts, and construction costs. Refined concepts will include geometric and structural design. Construction staging concepts will also be developed for each refined concept to allow constructability comparison. The project involves extensive subsurface utility engineering to relocate numerous buried utilities affected by the corridor improvements.

HR Green’s environmental assessment work centers on completion of an Environmental Impact Statement (EIS) and Record of Decision (ROD) for NEPA compliance. Other aspects of the environmental work included: early coordination letters and coordination of environmental scope meetings (including NEPA/404 concurrence point meetings). Additionally, HR Green is overseeing the completion of surveys of natural resource areas, including specific biological surveys to identify any endangered species/habitats and cultural resource surveys. This could include completion of draft 404 permit if necessary. Noise surveys and analyses are also being performed. The project corridor includes adjoining 4(f) and 6(f) properties and HR Green is performing the impact evaluation and documentation of potential impacts on these resources.

HR Green also prepared information necessary for all public involvement meetings, community advisory group (CAG) meetings, various coordination and project scope meetings, and will prepare materials and coordinate with Iowa DOT on the location/design public hearing.

Traffic analysis involved development of 2030 traffic forecasts and validation of the Metropolitan Planning Organization’s travel demand model. Traffic operations analysis involved an initial capacity analysis using Highway Capacity Manual methodologies and traffic simulation of the refined concepts.