Sabra, & Associates, Inc. (SAI) under two, successive, repeat on-call contracts with the County has performed a multitude of traffic engineering, projects, including:
Traffic Engineering to Support Roadway Projects - White Oak Transit Center
Traffic Analysis, Traffic Signal, and Maintenance of Traffic Design. Prepared traffic analysis to determine the impact of adding a new signal along Lockwood Drive, 200 feet east of the signal at MD 650. Used Synchro and SimTraffic to evaluate the signal. Work included preparation of base plans, coordination with highway, landscape and streetscape improvements, coordination with utilities, preparation of a design in conformance with MUTCD and Montgomery County guidelines, development of wiring and conduit schedules, preparation of specifications and engineer’s estimates.
Engineering On-Site Support: Provided on-site staff
TMC operators, Senior ITS Engineer for the ATMS upgrade project, and staff to support the Street Lighting section.
Signing Inventory and Upgrade
Performed inventory and review and construction inspection for 24 corridors under ARRA contract.
Traffic Signal Design
Prepared signal design plans for a new signal for Montgomery Village Ave/ Lake Shore Rd/ Walker Drive to be constructed.
Traffic Operations and Simulation
Performed analyses for at a 5-legged intersection on Wisconsin Avenue in Bethesda, including traffic signal phasing evaluations with respect to pedestrian conflicts, phase sequence, recommendations to safely and efficiently integrate a proposed upgrade to a high volume bicycle / pedestrian crossing into the existing traffic signal operation, and coordination and presentations to stakeholders. Conducted a traffic operations analysis at 4 closely-spaced intersections in a square configuration and developed recommendations for optimizing lane configurations and signal timing. Performed traffic data collection.
Traffic Operations Analyses for Special Event Planning
Performed traffic analysis in support of operational strategies for Congressional Golf Tournament in Chevy Chase. Developed a CORSIM model to evaluate bus routes, new bus stops and pedestrian impacts to traffic operations.
Intelligent Transportation Systems (ITS) – Evaluation of Alternatives to Long Term Power Outages at Traffic Signals
Performed research on the latest technology available for addressing mid to long term power outages at traffic signals, and developed short and long-term recommendations, time lines, and cost estimates for implementation.
Intelligent Transportation Systems (ITS) –Traffic Signal Cabinet Specification
Performed review of previous specifications, conducted stakeholder interviews consisting of signal designers, signal technicians, and ITS engineers, researched existing field cabinets and equipment, prepared outline of major cabinet items and alternatives, and developed a new traffic signal controller cabinet specification for use in Montgomery County.
Signal Timing Optimization
Prepared optimized timing plans for the Bethesda, Silver Spring, and Germantown CBD areas, and the MD 28, MD 586, and MD 189 corridors which consisted of 175+ signals. Work included the development of Synchro and SimTraffic models, implementation of the County’s new vehicle and pedestrian clearance interval policy, measurement of intersection widths and grades for the calculation of clearance intervals for vehicles and pedestrians, field observations to identify critical intersections and roadways segments, travel time/delay studies, assessment of the impact of the new clearance intervals on cycle lengths and phase splits, analysis of intersection operations including LOS, queues and delays, and the development and implementation of optimized signal timing plans.
Transit Signal Priority and Bus Rapid Transit Studies
Performed Systems Engineering Analysis, traffic operations analyses, and developed recommendations for best practices. State-of-the-Practice research, stakeholder interviews, technical presentations to stakeholders and Council, TSP technology assessment, performed traffic and transit analysis of 18 corridors for transit (route density, ridership, revenue hours and speed) and traffic (ADT, signal density, level of service, pedestrian volumes) MOEs, identified warrants for deploying TSP and granting priority requests including volume-to-capacity ratios and available slack time in signal cycle, and developed recommendations for integrating TSP into an RTS network including advanced strategies, upgraded technologies, performance measures, advanced concepts of operations such as headway based schedule maintenance, and costs.
7055 Samuel Morse Drive
Columbia, MD 21046
1502 Joh Avenue
Baltimore, MD 21227
100 M Street SE
Washington, DC 20003
8150 Leesburg Pike
Vienna, VA 22182