Sabra & Associates, Inc. has performed over 20 task assignments as a subconsultant under four BCS 2007-05 on-call traffic engineering contracts. The work included traffic accident analyses on arterial and interstate roadways and intersections, roundabout feasibility studies and conceptual designs, Synchro analysis, signal timing studies, congested intersection analyses, concept development and cost estimating, traffic signal warrant analyses, presentations at public meetings, origin-designation studies, corridor studies, and capacity analyses. Sample projects include the following:
MD 97 Corridor Study
Coordinated with Carroll County and the City of Westminster to evaluate existing and alternative capacity and level of service; evaluated queues and travel times; assessed planned and potential development activity and projected future traffic volumes; coded Synchro traffic model; tested proposed alternatives including new traffic controls, side street widening and new roadway connections; and developed conceptual geometry including bicycle compatibility, right-of-way impact and construction costs.
Congested Intersection Improvement (Fund 87) Studies
Performed traffic analyses at eleven intersections along congested segments of MD 140, MD 97 and MD 26 to evaluate the effectiveness of proposed improvements. The work included Synchro analysis, evaluation of Before/ After MOEs, preparation of existing and proposed condition diagrams, and LOS, queue and delay evaluations.
Candidate Safety Improvement Studies
Performed safety studies including the analysis of traffic data, measurement of queues, delays and speeds. Assessed physical and operational characteristics such as capacity and level of service, driver/pedestrian/ bicycle risky behaviors, conflict points, signal timing/clearance intervals, sight distance, shoulders and roadside features, illumination and pavement conditions. Developed mitigation measures including upgraded signing, pavement marking, signal phasing and timing and geometric improvements.
Traffic Operations Studies
Performed signal warrant and left-turn phasing studies, which included CLV, Synchro analysis, delay, gap, queue, spot speed studies, and analysis of historical crash patterns at MD 97 at Monticello Rd, MD 108 at Lark Brown, MD 108 at Sheppard Lane, MD 108 at Trotter Road, MD 108 at Summer Hollow, MD 80 at Carriage Hill Drive, US 1 at Kit Kat, US 29 Ramp at MD 103, and MD 97 at Carrs Mill.
Ramp Metering Evaluation
Performed ramp metering feasibility studies along I-70 at Marriottesville Road, and I-270 at MD 80. The work included construction of VISSIM and CORSIM models, field data collection of delays, speeds and queues, model calibration, alternatives analysis and technical memos.
Performed an alternatives analysis for adding an auxiliary lane on SB US 15 using VISSIM, and an intersection operations analysis for Jefferson Street using HCM and CLV. The work included travel time and delay studies, speed studies, coding the model, performing traffic analysis, review of historical crash data, use of the HSM to predict crash reductions, and preparation of conceptual plans.
MD 180 at Mt. Zion Road Roundabout Analyses
Evaluated the intersection for roundabout control under various geometric options (channelization, number of lanes, island diameter) and traffic volume scenarios (existing and future years). The analyses were performed using SIDRA as per Maryland SHA’s Roundabout Design Guidelines and Synchro.
MD 140 at Pleasant Valley Road
Prepared a signing and pavement marking plan for the addition of left turn lanes along MD 140.
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