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HomeMy WebLinkAbout5.1 - 1256 Traffic Operations along Major Corridors Page 1 of 8 STAFF REPORT CITY COUNCIL DATE: December 20, 2016 TO: Honorable Mayor and City Councilmembers FROM: Christopher L. Foss, City Manager SUBJECT: Traffic Operations Along Major Corridors Prepared by: Obaid Khan, Transportation and Operations Manager EXECUTIVE SUMMARY: On August 16, 2016, the City Council asked staff to prepare a report on the City’s existing and future traffic flow conditions and the Level of Service parameters at signalized intersections. This report also discusses the traffic signal synchronization and other traffic management approaches to minimize traffic congestion. STAFF RECOMMENDATION: Staff recommends that the City Council receive the staff report and provide input, if any, on traffic operations in the City. FINANCIAL IMPACT: None DESCRIPTION: On August 16, 2016, the City Council requested that Staff provide a report on the traffic flow conditions in the City including the Level of Service (LOS) at signalized intersections. Staff was also asked to provide a discussion on the future traffic conditions considering the full build out of the General Plan. In discussing the LOS and other traffic flow parameters, Staff has also provided information on various traffic management approaches that allow the improvement in traffic flow without the need of widening streets for additional travel lanes. These approaches include Traffic Signal Synchronization and Travel Demand Management. Information provided in this report is mostly from traffic impact studies that a re conducted as part of an environmental analysis related to California Environmental Quality Act (CEQA) standards. The CEQA requires that a lead agency (in our case , the City of Dublin) must conduct a traffic impact analysis due to a project if the impact s to the environment are considered “Significant” and the traffic analysis could provide the needed mitigations to mitigate the impacts. The City also conducts traffic studies that Page 2 of 8 are required to address a specific concern. These studies are usually focu sed in nature are designed to answer a specific question. An example of such a type of study includes a pedestrian safety review at a crosswalk to address pedestrian safety or analysis of a roadway segment for speeding concerns. Level of Service (LOS) Level of Service (LOS) of a traffic signal or a transportation facility is defined by the Highway Capacity Manual, which is published by the U.S. Transportation Research Board. LOS is used by cities throughout the country as a way to measure traffic flow. LOS is defined as a quantitative measure of service quality as perceived by the user of a transportation facility. It is divided into six levels from A to F with A being the “best operating conditions” with no impediments to the traffic flow and F represen ting the congested condition. LOS is used to translate complex numerical performance results into a simple A to F representative of travelers’ perception of the quality of service provided by a facility. Table 1 provides a brief description of LOS levels f or signalized intersections. Delay in this table represents the average delay experienced by all motorists at a signalized intersection. It should be noted that the delay increases with the increase in traffic. So as the traffic increases, more motorists attempt to enter and exit the intersection requiring additional time to be allocated to the signal which in turns increases the overall delay for all motorists. Table 1 - LOS Description Level of Service Description Delay in Seconds A Progression is extremely favorable and most vehicles arrive during the green phase. Most vehicles do not stop at all. < 10.0 B Progression is good, cycle lengths are short, or both. More vehicles stop than with LOS A, causing higher levels of average delay. > 10.0 to 20.0 C Some congestion may be noticeable. Individual vehicles may miss the green cycle, though many still pass through the intersection without stopping. > 20.0 to 35.0 D The influence of congestion becomes more noticeable. Longer delays may result from some combination of unfavorable progression, long cycle lengths, or high volume to capacity (V/C) ratios. Many vehicles stop, and the proportion of vehicles not stopping declines. > 35.0 to 55.0 E This level is considered by many agencies to be the limit of acceptable delay. These high delay values generally indicate poor progression, long cycle lengths, and high V/C ratios. Individual cycle failures are frequent occurrences. > 55.0 to 80.0 F This level is considered unacceptable with oversaturation, which is when arrival flow rates exceed the capacity of the intersection. This level may also occur at high V/C ratios below 1.0 with many individual cycle failures. > 80.0 The City uses LOS D outside the Downtown area as the target condition during peak congestion periods for our signalized intersections and strives to maintain it through Traffic Impact Fees (except for the Downtown area), project specific mitigations, and Capital Improvement Program. Page 3 of 8 Traffic Signal Synchronization Traffic delays along a street can be minimized through efficient operation of traffic signals. It allows the traffic to move from one signal to another in a platoon, and attempts to provide a green light to the platoon as it traverses from one signal to the next, thus minimizing the delay for traffic as it moves along the corridor. There are several items to consider in implementing traffic signal synchronization along a corridor. Partially and Fully Actuated Traffic Signals In order for a signal to be able to respond to waiting vehicle at an approach, it must be able to detect the vehicle. This detection of vehicle could be accomplished by Inductive Loops embedded in the pavement, through video cameras, radar, or heat sensing devices. The City uses the inductive loops except for signals along Dougherty Road, which will be fitted with video cameras after the completion of the current roadway widening project. All of the City’s traffic signals are able to detect waiting vehicles at an approach. Once a vehicle is detected, it must be able to “actuate” actions that allow the light to change to give the waiting vehicles a green light. A partial actuation refers to a signal that has main road that is actuated but not the side streets. Fully actuated signals are essential to implementing signal synchronization. Ability to Communicate with the Signals Direct communication link with traffic signals is critical in operating synchronized signals. It allows the City’s Traffic Operation Center (TOC) to communicate with signals in the field on allotting appropriate amount of time for various movements at different times of the day. Currently there are approximately 50% of the traffic signals in the City that are able to communicate with the TOC. Most of these signals are along major travel corridors. To access all traffic signals, additional or upgraded communication linkage will be needed to all traffic signals. Attachment 1 shows the current signal communication network in the City. Pedestrian and Bicycle Accommodation Any signal synchronization must take into account the amount of the State mandated time for crossing of pedestrians and bicyclists. The current State law requires providing adequate street crossing time at signalized intersections for pedestrians walking speed of 3.5 feet per second. This walking speed was recently decreased from 4.0 feet per second, and the City adjusted all traffic signals in 2014/15 to meet this requirement. Pedestrian times are usually the controlling factor in how much green time can be allotted to each street approach to the signal. As the width of an approach (governed by the number of lanes) increases so does the crossing time for pedestrians and bicyclists. This issue becomes significant for intersections like Dublin Boulevard and Doughert y Road and Dublin Boulevard and Tassajara Road, where the amount of time required for pedestrian crossing takes away significant amount of time from signal synchronization for vehicles. Furthermore, in 2012 the City Council adopted a Complete Street s Policy which requires the City to accommodate all modes of transportation for all users of all ages in Page 4 of 8 all transportation projects. This policy requires that Staff must balance the need of moving cars with the need for access and circulation of pedestrians, b icycles, and transit. Therefore it is a balancing act between meeting the State and the City mandated requirements, and the provision of a good signal synchronization. Types of Signal Synchronizations Time of Day (TOD) Signal Synchronization This type of signal synchronization allows signals to employ a Time of Day (TOD) scheme based on historical data. Usually this type of synchronization needs to be updated every three to five years depending on changes to traffic volumes. Currently the City has implemented TOD synchronization along Dublin Boulevard between Tassajara Road and San Ramon Road, Hacienda Drive between the I -580 freeway Ramps and Gleason Drive, and Tassajara Road between the I -580 freeway ramps and North Dublin Ranch Drive. TOD signal synchronization is ideal for a somewhat stable condition where a corridor experiences limited variations in traffic during peak times. It provides good progression of traffic during the peak time but may have some longer waiting times for side streets near the beginning and ending times (shoulders) of the peak. When Staff implemented the TOD synchronization along Hacienda Drive and Tassajara Road, some residents complained about longer wait times in early morning hours. Staff was able to modify the TOD synchronization to address these concerns by reducing or eliminating the TOD synchronization at few intersections along these corridors. Responsive and Adaptive Signal Synchronization: Responsive and Adaptive signal synchronization are the most advanced app roaches which require additional field equipment and faster communication network. These types of signal synchronization use real time data from the field and the traffic signal in the field selects the most appropriate timings within the pre-assigned range of signal timing parameters. The City and LAVTA jointly received a Federal grant in the amount of $1.7 million for the implementation of transit improvements and Adaptive Signal synchronization in the City. Staff is currently working with LAVTA on implementing this type of synchronization along Dublin Boulevard between Hacienda Drive and San Ramon Road. It is anticipated that this signal synchronization project will be complete by the Spring of 2017. Current and Future Status of Traffic Signal LOS in the City: The most recent analysis for various signalized intersections was prepared in February 2016 as part of the Kaiser Hospital Draft EIR. Table 2 shows the current and cumulative conditions of traffic signals along major corridors. The cumulative conditions represent the full build out of the City by 2040 along with a complete build out of the proposed Kaiser site. As reflected in Table 2, many of the intersections in the City remain at or above LOS D. Some intersections that exhibit lower LOS are those intersections that either have Page 5 of 8 physical limitations to street widening due to no available Right of Way or are not recommended to be widened due to the City policies mentioned earlier. It is also important to note that the intersections shown in Tab les 2 represent the most congested intersections in the City where the Kaiser Project related impacts were expected. Page 6 of 8 Table 2 - Existing (2015) and Cumulative (2040) Conditions No. Intersection Control1 Peak Hour Existing Conditions Cumulative 2040 Conditions Delay2,3 (Sec) LOS3 Delay2,3 (Sec) LOS3 1 Amador Plaza Road/Dublin Boulevard Signal AM PM 39 49 D D 38 108 D F 2 Village Parkway/Dublin Boulevard Signal AM PM 31 40 C D 43 >120 D F 3 Amador Plaza Road/I-680 Southbound Ramps Signal AM PM 9 11 A B 25 22 C C 4 Village Parkway/I-680 Northbound On Ramp Unsignalized AM PM 1 (5) 1 (3) A (A) A (A) 1 (6) 1 (4) A (A) A (A) 5 Dougherty Road/Dublin Boulevard Signal AM PM 40 46 D D 55 87 D F 6 Scarlett Drive/Dublin Boulevard Signal AM PM 8 9 A A 51 69 D E 7 Hacienda Drive/Dublin Boulevard Signal AM PM 41 41 D D 38 90 D F 8 Hacienda Drive/I-580 Westbound Ramps Signal AM PM 6 6 A A 8 40 A D 9 Hacienda Drive/I-580 Eastbound Ramps Signal AM PM 11 11 B B 18 46 B D 10 Tassajara Road/Fallon Road Signal AM PM 21 22 C C 20 25 C C 11 Tassajara Road/Gleason Drive Signal AM PM 28 23 C C 32 27 C C 12 Tassajara Road/Central Parkway Signal AM PM 28 18 C B 35 23 C C 13 Tassajara Road/Dublin Boulevard Signal AM PM 39 42 D D 113 >120 F F 14 Tassajara Road and Santa Rita Road/I-580 Westbound Ramps Signal AM PM 7 8 A A 16 36 B D 15 Santa Rita Road/I-580 Eastbound Ramps Signal AM PM 30 35 C C 59 91 E F 16 Brannigan Street/Dublin Boulevard Signal AM PM 14 13 B B 23 76 C E 17 Carnmore Place/Future Project Driveway/Dublin Boulevard Signal AM PM 4 3 A A 4 11 A B 18 Keegan Street/Dublin Boulevard Signal AM PM 11 9 B A 34 75 C E 19 Lockhart Street/Dublin Boulevard Signal AM PM 9 7 A A 27 57 C E 20 Fallon Gateway/Dublin Boulevard Signal AM PM 4 9 A A 5 44 A D 21 Fallon Road/Central Parkway Signal AM PM 13 11 B B 21 22 C C Page 7 of 8 22 Fallon Road/Dublin Boulevard Signal AM PM 19 14 B B 49 >120 D F 23 Fallon Road/Fallon Gateway Signal AM PM 5 11 A B 6 27 A C Notes: 1 SSSC = side-street stop controlled intersection; Signal = signalized intersection. 2 Average intersection delay calculated for signalized intersections using the 2000 HCM method. 3 For SSSC intersections, average delay or LOS is listed first, followed by the delay or LOS for the worst approach in parentheses. Source: Fehr & Peers, 2015. Travel Demand Management (TDM) Travel Demand Management (TDM) refers to project and programs that are implemented as part of the new development to reduce the expected traffic demand from the project. This approach has additional benefits for air quality and health as the TDM encourages people to use modes of transportation (walking, biking, transit) other than driving. Staff has implemented the TDM for the recently completed Persimmon Place project and the Kaiser Project has a ta rget to reduce traffic demand by 5% through a TDM program. The TDM program for Kaiser project include items such as shuttle service between the project and the Dublin/Pleasanton BART station, public transit subsidies, employer‐sponsored carpooling and ride‐matching programs, preferential carpool parking, guaranteed ride home, on ‐site car share program, scheduling practices to avoid peak‐hour travel (flex time, staggered shifts, compressed work schedules, etc.), end of trip facilities such as lockers, showers, or storage facilities, and provision of kiosks, website(s), brochures, etc. that provide information about the TDM program. Connected/Autonomous Vehicles Connected/Autonomous vehicle technology is another area that has a significant potential to reduce congestion by increasing roadway capacity. Since these types of vehicles could travel at a controlled speed and minimal space (headways) between cars, they have the potential to accommodate larger number of cars in the given space, thus providing additional capacity within the existing number of lanes. These technologies are moving forward at a fast pace and Staff is coordinating at the local and regional level to plan and program the needed infrastructure. The City is currently working with Livermore Amador Valley Transit Authority (LAVTA) to implement a pilot project using autonomous vehicles to connect Eastern Dublin BART station to businesses in the proximity. In conclusion, as the City’s General Plan continues to be implemented, there will be changes to traffic in the City. Some of these changes will be addressed through improvements to the transportation infrastructure through local and regional funds. However, some intersections may exhibit reduced level of service during AM and/or PM peak periods. These reduced service levels are not able to be mitigated due to limited right of way, City policies and/or State mandates. Staff will continue to address these impacted locations through enhanced signal timing and technology, as well as reducing the traffic demand through TDM programs. The Page 8 of 8 City has implemented or planning to implement wired communication to all traffic signals which will facilitate the implementation of newer technologies like Adaptive Signal Synchronization and Connected/Autonomous veh icles. NOTICING REQUIREMENTS/PUBLIC OUTREACH: None Required ATTACHMENTS: 1. 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