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HomeMy WebLinkAboutItem 7.1 Traffic Study Silvergate Dr (2) of AGENDA STATEMENT FjqO 45 Meeting Date: November 22 , 1982 SUBJECT Dublin Boulevard/Silvergate Drive - Traffic Study EXHIBITS ATTACHED Letter from Road Department dated November 17 , 1982; Exhibits A thru F; Memorandum from City Attorney dated November 8 , 1982 . RECOMMENDATION 1) Consider alternative designs proposed by Road Department 2) , Introduce and Adopt an Urgency Ordinance placing a stop sign at the northwest corner of Dublin Boulevard and Silvergate Drive. FINANCIAL STATEMENT: Cost. of improvement dependent upon alternative selected DESCRIPTION In accordance with City Council direction at its meeting of November 8, 1982 , the Alameda County Road Department has provided the City with additional information regarding proposed alternative designs* for the intersection of Dublin Blvd. and Silvergate Drive. The information requested included the following: 1. A detailed cost breakdown of alternative #2 which includes a stop sign at the northwest corner of Dublin Boulevard and Silvergate Drive. The cost and time frame of acquisition. The precise impact of alternative #2 on . adjacent property owners . Response #1 The estimated cost of alternative #2 would be approximately $29 ,500. This total includes the costs identified in Exhibit A by the Road Department, plus $1, 500 for the basic condemnation cost identified in the City Attorney' s memorandum of November 8 , 1982 . The cost of this project would be reduced to the extent that the County would-contribute. The County has tentatively indicated that it would contribute up to $14 , 000 for the improvement of this intersection. The City Attorney has indicated that the City can obtain an order for immediate possession and complete the intersection improvement upon deposit of the appraisal amount for the property which would need to be acquired with alternative #2 . The Road Department' s estimated time frame for construction is spring, 1983, if the City Council executes the agreement for the completion of this project prior to the end of 1982 . With respect to the impact of this project on adjacent property owners , the Road Depart- ment has determined that approximately 380 sq. ft. of right of way would be ----------------------------------------------------------------------------------------------------- COPIES TO: ITEM NO. ' AGENDA STATEMENT: Dublin Boulevard/Silvergate Drive - Traffic Study Page 2 acquired from the vacant lot at the northeast corner of Dublin Boulevard and Silvergate Drive. In addition, at least 2 on-street parking spaces would need to be eliminated in front of the property next to the vacant lot. 2 . Preparation of a low cost alternative which includes stop signs for all directions of travel along with any appropriate striping modifica- tions . Included with this alternative should be a detailed cost estimate. Response #2 The Road Department has prepared an alternative identified as Exhibit B in your packet which would stop traffic at all legs to the intersection and would require a slight modification of the movement of traffic for motorists heading westbound on Dublin Boulevard. The total estimated cost of this project including County overhead would be approximately $5 ,000 . 3 . Preparation of an alternative which would relocate the bike lanes on Dublin Boulevard to another location and include the modification of the center line on Dublin Boulevard by moving it to the south in order to provide a greater turning radius for motorists heading northbound on Silvergate Drive from Dublin Boulevard and which would obviate the need to acquire right of way from the property at .the southeast corner of Dublin Boulevard and Silvergate Drive and further, obviate the need to eliminate the parking for the residents adjacent to that vacant lot. Response #3 The County Road Department has prepared two alternatives which would accom- plish the objectives of alternative #2 without impacting either of the property owners at the northeast corner of the intersection. These alter- natives are identified as Exhibits E and F. In Exhibit E, the bike lane on the south side of Dublin Boulevard would be eliminated, the turning radius for traffic proceeding from Dublin Boulevard northbound to Silvergate Drive would be improved, motorists would be stopped at the northwest corner of the intersection and proceeding eastbound on Dublin Boulevard, traffic going to the church would not be required to stop, and there would be additional storage capacity in the left hand turn lane for that traffic. The total estimated cost of this project is $19, 375 . This includes the cost breakdown on Exhibit E plus an additional 25% for force account work and overhead charges by the County. The main difference between Exhibit F and Exhibit E is that Exhibit F would provide for the building up of the roadway on the south side of Dublin Boulevard in order to retain the bike lane on that side of the street. This alternative would cost the City approximately $31,250 . The cost of this alternative might increase to the extent that additional fill is required over and above the amount estimated in the engineer' s preliminary estimate. With both of these proposals , the County has indicated that it may contribute 50% or $14 , 000 , .whichever is less towards the proposed improvements . In addition to the information requested by the City Council, the Road Department has provided the City with traffic volume counts for the inter- section (Exhibit C) . As indicated in the traffic count information, the traffic generated from the newly opened church has substantially increased traffic flow thru the intersection. This increased traffic flow should be AGENDA STATEMENT: Dublin Boulevard/Silvergate Drive - Traffic Study Page 3 taken into consideration with respect to the storage capacity of the left hand turn lane on .Dublin Boulevard up to the church. Exhibits E & F and alternative #2 provide the greatest storage capacity for this traffic. The County Road Department has also prepared a comparison of the various alternatives to mitigate the vertical sight distance problem at Dublin Boulevard and. Silvergate Drive (see Exhibit D) . Each of these alternatives regulate the stop control at each leg of the intersection. The Road Department has indicated that any of these alternatives could be overlayed on the alternatives which deal with the horizontal alignment problem of the intersection. Staff has also discussed this intersection with Mr. Donald Zollinger, who lives adjacent to the vacant lot and whose on-street parking would be eliminated by alternative #2 . Mr. Zollinger vigorously opposes the elimination of his on-street parking. A representative from the Road Department will be present at the City Council meeting to discuss the various aspects of all alternatives. Irrespective of which alternative the Council views as .being most desirable, it is Staff' s recommendation that the City Council consider the placement of a stop sign at the northwest corner of Silvergate Drive and Dublin Boulevard as a temporary measure to mitigate the vertical sight distance problem. Although such a stop sign does not meet the traffic warrant criteria, it would improve the sight distance problem for motorists turning left onto Dublin Boulevard. The City Attorney has been directed to prepare an urgency ordinance to accomplish installation of such a stop sign. That ordinance will be available at the City Council meeting for Council con- sideration. `a`\O� QOM �9s COUNTY OF ALAMEDA Wt" a PUBLIC WORKS AGENCY PUBLIC 399 Elmhurst Street • Hayward, CA 94544-1395 °�� •:; ! '' WORKS, (415) 881-6470 Sources November 17, 1982 File: Dublin Blvd./ Silvergate Drive Mr. Richard Ambrose City Manager, City of Dublin P.O. Box 2340 Dublin, CA 94568 Dear Mr. Ambrose: This is in response to the Dublin City Council's request in its meeting of November 8, 1982 and your letter of November 10, 1982 with regard to the redesign of the Dublin Boulevard - Silvergate Drive Intersection. The total cost of Alternative No. 2, which consists of the realign- ment of Silvergate Drive at the intersection to a radius of 340 feet by acquir- ing a small wedge of right of way from an adjoining vacant lot, is estimated to be $28,000.00. This estimate would include construction, engineering, inspection and right of way acquisition; a detailed cost summary is shown in Exhibit A enclosed. Alameda County may, upon approval by the County Board of Supervisors, contribute 50% of the total cost of the project up to a maximum of $14,000.00 The project could be constructed in Spring, 1983 if the City Council executes the agreement for this project before the end of 1982. Approximately 380 square feet of right of way must be acquired from the vacant lot and at least two on-street parking spaces must be eliminated in front of the property next to the vacant lot. Exhibit B enclosed shows the alternative of providing stop signs at all legs of the intersection and a raised median on the easterly leg ,of Dublin Boulevard. This alternative, which is estimated to cost $4,000.00, was pre- sented to the City Council in its meeting on November 8, 1982; it was pointed out however, that the traffic volume-: at this intersection does not warrant stop control for all directions. Your attention is directed to Exhibit C, which shows the traffic counts conducted by this office at the intersection on November 3 to November .7, 1982 and Exhibit D, Which is a comparison of the advantages and disadvantages of the various alternatives to mitigate the vertical sight distance problem at the intersection. Two other alternatives, as shown in Exhibit E and F, to improve the horizontal alignment of the intersection were prepared. One of them is in accordance with your suggestion of relocating the bike lane on Dublin Boule- vard and the other one consists of widening Dublin Boulevard on the southerly :j Mr. Richard Ambrose November 17, 1982 Page Two side. Both alternatives could eleminate the loss of parking on Silvergate Drive, but both would necessitate a tighter alignment on the easterly leg of Dublin Boulevard. It is hoped that this additional information would help the City Council make a decision on the intersection. Please call Tat M. Cheung of this office at 881-6444 if you have any questions. Very truly yours, RONALD F. SORENSEN CHIEF, ROAD DEPARTMENT By TAT M. CHEUNG SUPERVISING CIVIL ENGINEER-DESIGN RFS:TMC:js Encl . cc: Ray Burnham EXHIBIT A Estimated Costs For Alternative No. 2 k Dublin Boulevard - Silver ate Drive Intersection I. Construction Costs Traffic striping and sign $ 2,500.00 New structural section 5,750.00 Median Curb 7,550.00 Concrete Removal 1,200.00 Imported Borrow 2,000.00 Miscellaneous 2,000.00 Sub-total $21,000.00 II. Engineering, Construction 5,000.00 Inspection III. R/W Acquisition and Appraisal 21000.00 Project total $28,000.00 CC Meeting: November 22, 1982 Item 7. 1 Exhibit #B is missing from the Staff Report WA ITS FOR FOUR-WAY STOP SIGNS f: 1. SIGNAL WARRANT Where traffic signals are warranted and need is urgent, the four-way stop is an interim measure that can be installed to control traffic while arrangements are being made for signal. installation. Satisfied Not Satisfied 2. ACCIDENT WARRANT Occurrence of 5 or more reported accidents of a type susceptible of correction by such control , within a 12-month period. (Types of accidents susceptible of correction in- clude right angle and left turn collisions). . No. of Accidents Satisfied No. Correctible Not Satisfied 3. MINIMUM VOLUME WARRANT A. A minimum average hourly volume of at least 500 vehicles entering the intersection from all direction for any 8 hours of an average day. Maximum 8 Hours Average per Hour Street Name Count of Max. 8 Hours Major Street Minor Street Total �J B. A combined vehicular and pedestrian volume from minor street must average at least 200 units per hour for the same 8 hours. Maximum 8 Hours Average per Hour Street Name Count of Max. 8 Hours Minor Street Vehicles Vehicles ` Pedestrian volume across major street Pedestrians Pedestrians .Total Units and delay to minor street vehicular traffic averages at least 30 seconds c`le dur- ing maximum hour. Average delay per vehicle on minor street seconds. A/ C. When the 85th percentile approach speed of major street traffic exceeds 40 MPH, the minimum vehicular volume warrant is 70 percent of above requirements of items 3A & 3B. Minimum Volume Warrant: Applicable Satisfied Not Applicable Not Satisfied' . �/ wigiT ly Ctrsdca� Date Z By Major Street Minor Street Street Name ��� d tad. 5"Iti er a l or Total Peak _ — -- - --- -j--- --- Entering Hours Direction �� Sill Traffic Hour Totals Totals 0700-0800 �� J �� C� 8 _ f 29 12- 1 0800-0900 6 79 7a 2 50 160 0900-1000 3 7 1000-1100 2-0 106 Z S ,; 1100-1200 (a q 7 3 2- I Jr 1200-1300 3' 5�` p q 3� ` 3 1 1300-1400 a-7 37 1400-1500 a ��(� 3�-F // 3 1500-1600 Z`� ' (FU' 1600-1700 SO F']i /+-3 1700-1800 -7 /06 113 e- q g, Z 1800-1900 7 YE /2 Z 1900-2000 3o Z Totals ,3q �-� 567 7 q 8-Hr. Totals 3y`� 1• • , 1 1 ATIO I i DAY 'F ®� S� :Y / :Y �O • . :v ' in :Y •y �Y • • • ®� ®■ • : • ry ' 1 PM �. 1 • PM ' _' _■ 24 HR. TRAFFIC - i irk AM PEAK i . 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M/ • �w r0^'�J rjL- e`7VIA 4T -� toltr �i sow o�t y • -l � ''' '� W •M d a 1•� 0 )Cxx lAol ��.+CC—, •o% I CC Meeting: November 22, 1982 item 7. 1 Exhibit #E&F is missing from the Staff Report MEMORANDUM TO: City Manager FROM: City Attorney DATE: November 8, 1982 SUBJECT: Condemnation Costs/Time Dublin Boulevard-Silvergate Drive Intersection Improvements Regardless of what alternative is selected or whether bike paths are included, the basic condemnation costs would be $1 ,000-$1 ,500 to merely file a lawsuit. If 'a property owner contests the litigation (typically, the purchase amount being offered) ,' the costs would increase at a rate of $75.00 per hour for each hour :.`.spent 'on the lawsuit."',.. The land acquisition necessary for this project would not require an expensive appraisal , unless of course, the acquisition is contested. County right of way should be able to do the appraisal necessary to file the suit. Qualified ap- praisers currently charge $50-$65 per hour. To the above costs, the fair market value of the land should be added. This is apparently in the range of $3.00 per square foot. :Upon deposit of the appraisal amount, the City can obtain an order for immediate possession, and complete the intersection improvement. Trial of the matter might not occur until 8-10- months after the filing of the action. Title would not rest in the City until settlement or trial .