I-95 Express Toll Lanes
Traffic Engineering Design and Planning - 2014

SAI prepared a multitude of traffic engineering design and traffic analysis for the reconstruction of 11 miles and 5 interchanges on I-95 to provide Express Toll Lanes.


  • CCTV, DMS, Signal, Wireless
    and Fiber Communication Design
  • Signing , Pavement Marking
    & Lighting Design
  • Traffic Analyses, Modeling


Signing Concept Plans
SAI prepared the signing concept plans for I-95 section, which consist of 11 miles of highway (I-95) and 5 interchanges with both general purpose and managed (toll) travel lanes. The work included inventory and evaluation of existing signing, development of 24 base plans, development of conceptual layouts, meeting with MdTA and the GEC to refine the concepts, develop of final plans include sign size layout, detailed location design and support type selection. The plans were developed to a50% completion state and handed over to the segment designers for incorporation into the final plans.

I-95 Final Design and MD 43 Interchange Final Design Contracts (KH 1401, 1402 and 1403)
SAI prepared interchange selection and alternative traffic LOS and simulation analyses for the MD 43 at I-95 ultimate and interim interchange configurations.  SAI prepared interchange signing and marking (over 50 plan sheets), lighting, traffic signalization and interconnect (3 ultimate signals and 6 temporary signals) and ITS (10 DMS signs, 5 CCTV Cameras, 2 Automatic Traffic Recorders, 7 Toll Rate Signs and for preparing details for conduit layout for ITS devices on 5 Toll Gantries) design. Prepared lighting designs for all three contracts. Photometric analysis including point by point calculations on the proposed pavement surface, light trespass calculations, and veiling luminance calculations. The project included lighting for 1 interchange, continuous lighting along general purpose and managed lanes, underpass lighting, and sign lighting throughout the project limits.

I-95 at I-895 Interchange Final Design Contracts (KH 1501, 1502 and 1503)
SAI prepared traffic signalization design for 2 Baltimore City intersections and ITS design. The ITS designs included 8 DMS signs, 5 CCTV Cameras, 2 Automatic Traffic Recorders, 2 HARs, 2 Over Height Vehicle Detection Systems, 4 Toll Rate Signs, 4 Travel and Toll Information Signs, Power and Communications to 2 Automatic Gate Controllers, and Power and Communications to 2 Toll Gantries. In addition, SAI also developed the ITS standards, special provisions, and structural design and mounting details.  SAI is also responsible for all sighting analysis of all CCTV, DMSs, RWIS, and HARs designed under these contracts including coordination with various utility companies including electrical, telephone and fiber optic.

Corridor-Wide Traffic Analyses
SAI performed Highway Capacity Manual analyses for the IAPA report. Analysis time periods were the weekday AM and PM peak periods and included Basic Freeway Segments, Weaving, and Ramps.  SAI was also responsible for the preparation of a VISSIM model of the proposed geometrics of I-95 Section 100. The simulation models consisted of 8 interchanges and over 15 miles of interstate highways. The simulation was prepared for 2025 Build conditions and 2010 Build and No-Build conditions. CORSIM models were also developed to double check the results of the VISSIM analyses.

Columbia Maryland

7055 Samuel Morse Drive
Suite 100
Columbia, MD 21046
Phone: 443-741-3500
Fax: 443-741-3700

Baltimore Maryland
1502 Joh Avenue
Suite 100
Baltimore, MD 21227

Phone: 410-536-3653
Fax: 410-536-3654

Washington, D.C.

100 M Street SE
Suite 550
Washington, DC 20003

Phone: 202-570-7080
Fax: 202-697-5007

Vienna, Virginia

8150 Leesburg Pike
Suite 630
Vienna, VA 22182

Phone: 703-942-8990


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