Location: Auxiliary Lane, Westbound State Route 91, Green River Road to State Route 241

Engineering/Environmental Studies and Project Design: Completion in late 2019

Construction: Dependent upon project approvals and funding. Could begin in 2020; earliest anticipated opening date is fall 2021

Investment: $6.8 million for environmental studies and design; estimated $36.2 million for construction


The Riverside County Transportation Commission, in partnership with Caltrans, the Orange County Transportation Authority, the Transportation Corridor Agencies, and the City of Corona, is conducting engineering and environmental studies to support the 91 Corridor Operations Project. RCTC is leading development of the project. 

The proposed project would add an auxiliary lane on westbound State Route 91 from the Green River Road on-ramp to the southbound State Route 241 connector. The auxiliary lane, located next to the exterior shoulder, would help relieve westbound traffic congestion through this heavily traveled corridor.

RCTC is working closely with project partners to complete the project approvals/environmental document. Project funding has not been determined and will require future direction from the RCTC Commission.

Click here for the latest quarterly project status memo from RCTC

Pending project approvals and securing funding, work could begin in 2020 and would take about 15 months to complete. The earliest anticipated opening date for the new auxiliary lane is fall 2021.

  • March 2017: RCTC opens new general-purpose lanes and the 91 Express Lanes as part of the 91 Project on March 20.
  • February – April 2018: RCTC gathers data related to traffic conditions to evaluate mobility on the 91 corridor. RCTC evaluates several options, including recommendations from the public, to improve traffic flow.  Operational improvements to the 91 Express Lanes, including changes in striping, signage and channelizers, are initiated. 
  • May 2018: Commission votes to expend surplus 91 Express Lanes revenue to implement the 91 Corridor Operations Project, including:
    • Restriping of the northbound I-15 entrance to the 91 Express Lanes,
    • Restriping of westbound 91 at the Riverside/Orange County Line entrance/exit of the 91 Express Lanes,
    • Studying the Green River Road on-ramp meter, and
    • Conducting project development for environmental approvals and final design for the addition of a westbound 91 auxiliary lane from the Green River Road on-ramp to the southbound State Route 241 connector, and conducting a traffic and revenue study for the westbound auxiliary lane, with a return to the Commission in fall 2018 with recommendations. 
  • June 2018 and September 2018: Caltrans conducts two field studies, in which the ramp meter is temporarily turned off at the westbound 91 Green River Road Interchange.
  • September 2018: Crews restripe northbound I-15 entrance to 91 Express Lanes
  • November – December 2018:  Crews restripe westbound 91 at the Riverside/Orange County Line entrance/exit of the 91 Express Lanes. Commission receives report of ramp meter study and opts to keep ramp meter in place and receives results of a traffic and revenue study and cost estimates for the westbound 91 auxiliary lane. Commission votes to continue environmental studies and final design for the westbound 91 auxiliary lane, with direction to return to the Commission at a future date to determine funding options and priorities.

News Updates (2004-2015)

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