KOA was selected by the City of Corona to make improvements to Ontario Avenue at the I-15 Interchange. Ontario Avenue consisted of six lanes west of the I-15 interchange and four lanes just east of the interchange. Close to the interchange was the Compton Avenue intersection that would also be impacted with the proposed widening. The project required improvements to the interchange by adding additional lanes to Ontario Avenue below the I-15 bridge structure. KOA completed a detailed traffic study to determine the number of lanes needed for interim improvements. Six alternatives were considered to meet the City’s threshold level of service “D” at the intersections. Proposals included adding at least one additional lane in each direction. The improvements would require construction of tie-back walls to achieve the proposed widening. The project included coordination with Caltrans District 8 for proposed improvements using the Streamlined Oversight Process. This project was shelved after preliminary design plans were completed because the City lost funding for the project.