Lochmueller Group (Lochgroup) served as subconsultant for the design of a replacement viaduct for Kingshighway over the Union Pacific Railroad just south of I-44. Kingshighway is the busiest arterial street in the City of St. Louis providing 6 lanes of traffic along a key north-south axis. Built in 1936, the railroad viaduct was in poor condition and in need of replacement.
Lochgroup provided traffic engineering, which included traffic modeling, construction traffic mitigation planning, and traffic signal design. The traffic engineering work was governed by local (City of St. Louis and Missouri Department of Transportation) standards and procedures. Lochgroup’s modeling focused on evaluating improvements planned for the intersection of Kingshighway and Shaw Boulevard at the north end of the viaduct. The intersection was relocated to the south, the east leg was entirely realigned, and a new southbound left-turn movement was introduced to enhance access to the Missouri Botanical Garden (a major regional attraction) located on Shaw Boulevard to the east.
In addition, the project included modifications to the I-44 eastbound off-ramp at Kingshighway. The ramp was widened for a second right-turn lane onto Kingshighway to serve motorists making the new southbound left-turn movement at Shaw Boulevard.
VISSIM and Synchro traffic flow models were developed for a 1-mile stretch of the Kingshighway Corridor between Manchester and Vandeventer/Southwest Avenues. VISSIM is a traffic simulation tool with sophisticated driver behavior models that accurately replicate complex traffic operations, including the interactions of closely-spaced signalized intersections. These models were carefully calibrated to field conditions during rush-hour peak periods.
Through this work, Lochgroup helped St. Louis determine the most effective configuration for the intersection of Kingshighway and Shaw Boulevard and confirm that the modifications would not adversely impact traffic along the critical Kingshighway corridor.