Traffic Signal Design and
Intelligent Transportation Systems
CHS Consulting Group’s licensed engineers are leaders in cutting-edge technologies and current practices in ITS. We have extensive experience in designing signal priority systems along LRT and BRT lines, safe pedestrian crossing signals (PHB and RRFB), red light camera enforcement, signal interconnect involving combined hardwire, wireless technologies (such as spread spectrum radio technology), and areawide traffic signal systems. We also bring to each of our projects a thorough understanding of signal operations and state-of-the-art signal controllers, vehicle detection, and communications technologies.
Areas of Expertise
Signal Interconnect
Areawide Signal System Planning and Design
Transit Signal Priority System
Pedestrian Hybrid Beacon
Rectangular Rapid Flashing Beacon
Mission Bay Development
Project Overview
This 302-acre urban infill development project is located in a former rail yard site and includes more than 10 million gross square feet of academic, research, medical, office, retail, and hotel development, which is fully integrated with the Muni Third Street Light Rail line service and several freeway ramp interchange improvements.
CHS Role
CHS Consulting Group’s President Chi-Hsin Shao has been involved in this project for more than 30 years, beginning as the City of San Francisco’s lead professional during the initial planning phase. Over the past 15 years, CHS has worked closely with the University of California, San Francisco (UCSF) on transportation services to its new Mission Bay campus and evaluated its shuttle routes. CHS developed site plan-level analyses for several Mission Bay blocks as part of several major phase planning studies.
CHS has served as traffic engineer for the various Mission Bay projects, providing traffic signal design, signing and pavement delineation design, and traffic control plan preparation. CHS designed or modified a total of 24 signals and prepared signing and pavement delineation for 34 city blocks, as well as a roundabout at Mission Bay Drive and Berry Street. The 24 traffic signals include several along 3rd and 4th Streets that require a signal priority system for MUNI light rail trains. At-grade Caltrain rail transit crossings are located at 7th and 16th Streets, as well as Mission Bay Drive at 7th and Berry Streets. In addition, there are three I-280 Caltrans signals: one at the I-280 on- and off-ramps at King and 5th Streets and the other two at the I-280 on-ramps and off-ramps at Mariposa Street.
California High-Speed Rail Initial Construction Segment 1 ITS Elements
Project Overview
The California High-Speed Rail Authority is developing an 800-mile high-speed train system that will operate at speeds of up to 220 miles per hour. Design and construction are beginning on the Central San Joaquin Valley Segment, the backbone of the system. Initial Construction Segment 1, the first phase of the project, extends approximately 29 miles from southern Madera County to the City of Fresno. The project is being delivered by design-build contract with a cost of $1 billion for Segment 1 . The project will require grade separation of the HSR track alignment and city streets throughout the City of Fresno. The grade separation improvements impact nearly 70 intersections, 19 miles of roadway, facilities, intersection safety lighting, the City’s extensive ITS infrastructure, and Caltrans highway electrical facilities.
CHS Role
CHS Consulting Group is responsible for all traffic engineering plan development, including traffic signals, roadway and railway lighting, temporary signals and lighting, railroad interconnect and preemption, electrical service planning, highway lighting, traffic operation systems, and intelligent traffic systems within State of California and City of Fresno rights-of-way. CHS is developing and designing interim and permanent ITS system improvements to fiber optic facilities, wireless broadband radio, changeable message signs (CMS), flashing beacons, intersection safety lighting, and vehicle priority systems. These designs are extremely complex, and include fiber optic or wireless radio interconnect, ATMS traffic signal controllers, communication controllers, EVP, and IP cameras. Two cross town trunk lines for all city fiber, and Caltrans’ trunk for the entire State Route 180 corridor required disruption as HSR improvements tunneled under the highway and fiber. They also required the development of a temporary high bandwidth wireless radio system as part of the construction staging improvements.
Marin Transit Redwood and Grant Transfer Center Improvements
Project Overview
The Redwood and Grant Transit Improvement Project in downtown Novato was a coordinated effort between Marin Transit, Golden Gate Transit, and the City of Novato to provide safer and more convenient access, safe and comfortable features for transit users, and improvements for bus and traffic operations. The facility improves pedestrian access with raised pedestrian crosswalks within the facility and signalized crossings of Redwood Boulevard, the major thoroughfare through Novato.
The redesigned transit center also includes a combined center platform to provide a more attractive and functional facility. Transit vehicles cross other vehicle paths on entry and exit to the center island, which allows it to serve standard buses from multiple agencies, rather than dual-door buses. This innovative contraflow design is offset from the roadway, highly visible, ADA-compliant, provides increased capacity, and allows transfers to be completed without crossing bus lanes.
CHS Role
CHS Consulting Group designed and implemented a transit signal priority responsive system (TSP) for the ingress and egress operations, pedestrian- and transit-initiated midblock signalized pedestrian crossings, and interconnect with adjacent signalized intersections. CHS also responded to concerns about conflicts of contra-flow design and possible sightline issues when buses enter traffic flow along Redwood Boulevard and a queuing issue within the center as well as along Redwood Boulevard on egress.
We devised a creative solution that meshes with the City of Novato’s existing traffic signals. The solution combines an integrated pedestrian- and transit-actuated signal at the hub with TSP and interconnect in the adjacent intersections. The implemented operations plan includes development of system phasing and timing sheets and direct connection of input/output interconnect, eliminating bus queues on exit and increasing throughput while simultaneously enhancing passenger and pedestrian safety.
