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HomeMy WebLinkAboutItem 8.4 Caltrans Alcosta Onramp Closure *" ~~ . CITY CLERK File # D[B]0[Q]-~BJ AGENDA STATEMENT CITY COUNCIL MEETING DATE: March 16, 1999 SUBJECT: Consider Caltrarls' Request to Temporarily Close the Alcosta Boulevard Southbound On-ramp to Interstate 680 Report prepared by: Lee S. Thompson, Public Works Director ATTACHMENT: Caltrans Letter dated March 8, 1999 RECOMMENDATION;vvi Concur with Caltrans' Proposed Alcosta Boulevard On-ramp Closure and '\ direct Staff to respond in writing to Caltrans' request. FINANCIAL STATEMENT: No impact on City funds . DESCRIPTION: Staff from the State Department of Transportation (Caltrans), California Highway Patrol (CHP), Dublin, San Ramon and the Alameda County Transportation Authority have met on several occasions to discuss the status of ongoing construction work at the southbound 1-680 Alcosta Boulevard on-ramp, in conjunction with the I580/I680 Direct Connector project. Included in the discussions were the impacts of construction work to motorists traveling on the mainline and to those using the Alcosta Boulevard on-ramp. Presently the shoulder area along the ramp is barricaded with construction barriers minimizing the shoulder recovery area at the junction with mainline 1-680. Recent complaints received by Caltrans about the on-ramp condition and an increase in accidents over 30% between October 1998 and January 1999 necessitated the need to improve motorists' safety at this location. To improve safety at this location during construction, Caltrans has examined three alternatives; 1) Additional signage, 2) temporary conversion of the right most lane of 1-680 into an auxiliary lane for 9 months, and 3) temporary closure of the Alcosta Boulevard on-ramp for 2 ~ months. After considering the potential impacts of the three alternatives, Caltrans and CHP have concluded that the temporary on- ramp closure is the most viable alternative to improve safety. Caltrans has sent a letter to Dublin and San Ramon requesting both cities to consider and concur with their proposed Alcosta Boulevard on-ramp closure between April 1, 1999 and June 14, 1999. This will allow completion of the planned work along the on-ramp in one continuous phase rather than spread over the next 9 months. Caltrans will provide signage and advance notices of the closure. . COPIES TO: ITEM No.M g; agenmisclagend. 680olf.ramp.doc The proposed temporary closure of the on-ramp would divert some freeway traffic to City streets, primarily San Ramon Road. This may require retiming of some of the City's traffic signals to accommodate additional traffic mainly during the morning commute hours. Caltrans has indicated that they will monitor traffic circulation at major intersections and work with the City to mitigate the impacts. ACTA will participate in paying the City for actual cost incurred up to a total of $5,000 to retime impacted traffic signals. Staff agrees that the situation is now a safety problem, and that the 2Yz-month impact is preferable to the 9-month solution, and concurs with Caltrans recommendation to temporarily close the Alcosta Boulevard southbound on-ramp to 1-680. The City believes this closure will improve motorists' safety. If implemented, staff will monitor the effects to City streets and make the necessary signal adjustments to keep traffic flowing smoothly. -- ;2 - .. . . . .. STATE OF CA' '-ORNIA - BUSINESS TRANSPORTATION AND HOUSING AGENCY GRAY DAVIS G"""",c>' DEPARTMENT OF TRANSPORTATION POBOX 23650 OAK:AND, CA S4S2~ . (510)285-4444 IDD (510) 286--4454 March 8, 1999 f.1ECEtVEf'I MAR 1 0 13S~ PUBLIC VIIORr~S 04-Ala-580-19.8/21.0 04-Ala-680-19.71R21.9 04257 233924 Direct Connector Proj ect ... . .. . .-.; - ,- f.,,.,,..._'" Mr. Lee Thompson City Engineer City of Dublin 1 00 Civic PlaZa P.O. Box 2340 Dublin, CA 94568 Dear Mr. Thompson: Thank: you for the City's participation in the meeting on February 24, 1999 to discuss impacts of the upcoming work at the southbound 1-680 Alcosta Boulevard on-ramp. According to the current schedule submitted by the contractor, the work at this location would require 47 working days. However, the contractor's ability to complete the work is planned for December 1999, as the work would be performed at various times during the upcoming months. Given the present conditions, proceeding with the work as planned is not desirable, and will not alleviate the public safety concerns and complaints. . Accident data for the period of October 1998 through January 1999 and during the same period for the prior year were provided in the meeting. The accident data were provided by the CHP, and covered the segment of southbound 1-680 between the Alcosta Boulevard on-ramp and the Amador Valley Road Undercrossing. The data shows the number of accidents increased from 19 to 25, an increase of over 30%. Although the information is not detailed enough to determine the exact causes, we contend the-majority of the accident increase occurred at the on-ramp. This assertion can be supported by the recent complaints received from the public about the on-ramp conditions, and recommendation by the CHP to temporarily close the on-ramp. To improve the safety at this location, we have examined the following three alternatives: 1) Additional signage 2) Temporary conversion of the no. 4 lane into an auxiliary lane for 9 months 3) Temporarily close the on-ramp for 2 ~ months . The additional signs installed several months ago has helped the situation, but not to the extent that it would solve the problem. CHP concurs that further additional signage, as proposed in Alternative 1, is not the appropriate solution. In Alternative 2, temporary conversion of the no. 4 lane to an auxiliary lane would introduce additional new merging and weaving conflicts. Merging the no. 4 lane to the no. 3 lane north of the on-ramp would be necessary. The motorists traveling to 1-580 would then be required to weave onto the auxiliary lane. In Alternative 3, closure of the on-ramp would create minor inconvemences to the local residents in both the Cities of San Ramon and Dublin, and might require signal timing adjustments to some of the major signalized intersections. ~- .. :Mr. Lee Thompson M:arch 8, 1999 - Page 2 .- . Therefore, after considering the potential impacts of the three alternatives, we conclude that Alternative 3, temporary on-ramp closure, is the most viable. TIlls alternative would allow completion of the planned work in one continuous phase rather than spread over the next 9 months; and thus, provide earlier improved on-ramp access by as much as six months. We believe implementing this alternative would best serve the public's safety and interest. We have discussed this alternative \-vith the contractor and propose to close the on-ramp between April 1, 1999 and June 14, 1999 pending your approval.. We are confident the work can be completed within the proposed timeframe. However, completion of the work is weather dependent. We have relocated the temporary railing and light fixture to allow a 5-foot outside shoulder for emergency maneuvering until the proposed on-ramp closure is implemented. It should be noted that the Alcosta Boulevard on-ramp has been closed on several occasions during non-peak hours. We have not received any complaints regarding the closures. It is our understanding that the City also has not received any complaints. Should this on-ramp be closed as proposed, we will monitor traffic circulation at major intersections and work with both the Cities Dublin and San Ramon to remedy the impacts. Our understanding from Mr. Francis Lo who represents the Alameda County Transportation Authority (ACTA) for this proj ect is ACTA will participate in paying the cities for the actual cost incurred up to a total of $5,000 to adjust . the signal timing. To best serve the public and to provide a safe construction work area, we request the City to consider and concur with the proposed Alcosta Boulevard on-ramp closure. ... If you have any questions please call me at (510) 286-5125 or Rubin Woo, Assistant Project Manager, at (510) 286-5086. Sincerely, Rt\RRYY. YAHATA District irector PATRlCKK. PANG Project Manager c:Ferdinand Del Rosario - City of Dublin John Dillon - City of San Ramon Lieutenant McElroy - California Highway Patrol Christine Monsen - Alameda County Transportation Authority Francis Lo - CCS Planning & Engineering .