84 Expressway Widening and State Route 84/I-680 Interchange Improvement Project

84 Expressway Widening 680 location map

Update: Lane Closures on State Route 84 Between Ruby Hill Drive and I-680 through May 21, 2021


The California Department of Transportation (Caltrans), in cooperation with the Alameda County Transportation Commission (Alameda CTC), proposes to widen and conform State Route (SR) 84 to expressway standards between south of Ruby Hill Drive and the Interstate 680 (I-680) interchange. The project would also improve SR 84/I-680 interchange ramps and extend the existing southbound I-680 High Occupancy Vehicle/express lane northward by approximately 2 miles.

Project Purpose

  • Alleviate existing and projected traffic congestion to improve SR 84 as a regional connection between I-680 and I-580, consistent with other local and regional planning and programmed projects
  • Improve traffic circulation between SR 84 and I-680, and in the vicinity of the SR 84/I-680 interchange
  • Improve safety for motorists and cyclists on this segment of SR 84
  • Complete the statutory designation of this segment of SR 84 as an expressway facility

Project Scope

  • Widen SR 84 to a 4-lane expressway between south of Ruby Hill Drive and the I-680 interchange
  • Concrete barriers will be placed in the median
  • Shoulder rumble strips will be placed between travel lanes and the shoulders
  • Consolidate existing vehicle access openings, private driveways, and rural roads to new frontage roads
  • A new signalized intersection at Little Valley Road/Vallecitos Atomic Laboratory Road
  • A Class II bikeway will be provided in each direction of SR 84
  • Construct an approximately 1,000-foot-long auxiliary lane on southbound I-680 to the south of Calaveras Road/Paloma Way, and realign the on-ramp from Paloma Way to southbound I-680
  • Reconstruct the off-ramp from northbound I-680, construct a new flyover ramp from Calaveras Road to northbound I-680, and construct a new slip on-ramp from Calaveras Road to northbound SR 84
  • Realign the southbound SR 84 to northbound I-680 connector to merge with the northbound on-ramp to I-680 from Calaveras Road
  • Add an HOV preferential lane to the existing two-lane southbound SR 84 to southbound I-680 on-ramp
  • New Class I bikeway through the interchange area to connect the southbound SR 84 Class II bikeway with Paloma Way
  • New Class II bikeway along the northbound I-680 on-ramp from Calaveras Road to connect with the northbound SR 84 Class II bikeway
  • Extend the existing HOV/Express lane on southbound I-680 northward, a distance of approximately 2 miles.

Anticipated Schedule

Detailed Design: June 2018 - December 2020
Right-of-Way: June 2018 -December 2020
Construction: May 2021- Spring 2025


For additional information, contact Public Information Officer Janis Mara at Janis.Mara@dot.ca.gov