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Baltimore Red Line: Challenges of a Large Model Area PowerPoint Presentation
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Baltimore Red Line: Challenges of a Large Model Area

Baltimore Red Line: Challenges of a Large Model Area

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Baltimore Red Line: Challenges of a Large Model Area

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  1. Baltimore Red Line: Challenges of a Large Model Area Presented by: Mahmood Shehata, P.E. McCormick Taylor, Inc. Philadelphia, PA Presented to: PTV Users Group Meeting May 16, 2008 Philadelphia, PA

  2. Presentation Topics • Introduction to Baltimore Red Line • Work Sharing and Modeling Standards • Downtown Base Model Development • Model Calibration Techniques and Obstacles • Coding of Alternatives – Including TFlow Fuzzy • Lessons Learned

  3. Introduction to Baltimore Red Line

  4. Introduction to Red Line • 12-mile East-West Corridor • Western Suburbs through Downtown Baltimore to Eastern End of Baltimore City • Potential BRT or LRT Corridor • Alternatives Analysis for DEIS and New Starts

  5. Red Line Corridor

  6. Existing Transit Services • Local, Express, and Commuter Bus • Metro Subway – NW Suburbs to Downtown Baltimore • Central Light Rail Line – Northern Suburbs through Downtown to Southern Suburbs and Airport • MARC Commuter Rail – From NE Suburbs to SW Suburbs and Washington, DC • Existing E-W service limited, including only one high-speed bus line

  7. Comprehensive System • Red Line Part of Regional Plan • Expand Existing System

  8. Three Distinct Areas • Proposed Line Serves 3 Distinct Areas: • West Baltimore and Western Suburbs • Downtown Baltimore • East End (Fells Point / Canton) • 22 Proposed Stations

  9. West Baltimore and Western Suburbs Security Boulevard – MD 122 Eastern Terminus of I-70 – Proposed Station Location US 40 in West Baltimore

  10. The “Trench” US 40 Between West Baltimore Commuter Rail and Downtown

  11. Downtown / Inner Harbor Baltimore St - Location of Most Alignments Pratt St – Source of Congestion in VISSIM Models

  12. Fells Point / Canton Wider Boston Street to south of City Grid in Canton Area Narrow Street Grid in Fells Point

  13. Work Sharing and Modeling Standards

  14. Work Sharing and Modeling Standards • Synchro initially utilized to evaluate corridor • MTA and project team agreed upon VISSIM to analyze entire corridor, including preemption and TSP • Five Separate Consultants to complete VISSIM models • Single consultant chosen for oversight

  15. Work Sharing and Modeling Standards • Each consultant assigned a portion of study area to model • Model Areas chosen using logical break points: • 1-2: Park and Ride (Baltimore County and West Baltimore) • 2-3: W.Baltimore MARC Station • 3-4: US 40 / MLK Blvd. • 4-5: President St / Central Avenue

  16. Model Areas 1-2 Modeling Team 1 Area Modeling Team 2 Area

  17. Model Areas 2-3 Modeling Team 2 Area Modeling Team 3 Area

  18. Model Areas 3-4 Modeling Team 3 Area Modeling Team 4 Area

  19. Model Areas 4-5 Modeling Team 4 Area Modeling Team 5 Area

  20. Work Sharing and Modeling Standards • Standards Developed for Modeling Consistency • Speed profiles, turning speeds, links and connectors, etc. • Vehicle profiles uniform – including articulated buses and LRT vehicles • CD Distributed with base .inp file • Provided identical vehicle profiles for all models. • Aerials with .bgr - georeferenced models

  21. Work Sharing and Modeling Standards • Spreadsheet Developed and Distributed to Ensure Model Consistency

  22. Work Sharing and Modeling Standards • Standards were developed for most components of VISSIM models

  23. Downtown Model Development

  24. Downtown Model Development • Approximately 95 signalized intersections • N-S Arterials on east and west end • Alternating one-way E-W Streets

  25. Downtown Model Development • Synchro base model previously developed • Small blocks, Unique Lane and Turn Restrictions • VISSIM model developed from scratch • Divided into 3 sections to setup model: • MLK to Howard (600-650) • Howard to Calvert (650-700) • South to Central (700-750) • Read Additionally used

  26. Unique Characteristics of Downtown Model • On-Street Parking / Loading Zones in some locations • Off-Street Parking as source/sink • Initial Model did not include Conway Street • At times, I-95 and I-395 backs into Conway St

  27. Unique Characteristics of Downtown Model Initial Model Area Conway St. Intersection of Howard and Conway Constricting Point

  28. Unique Characteristics of Downtown Model • Routing decisions through 2,3, even 4 intersections (in existing conditions model)

  29. Unique Characteristics of Downtown Model • Model accounts for high pedestrians, including Leading Pedestrian Intervals

  30. Public Transportation System • Bus routing and headways obtained with established schedules • Bus stops field verified • Central Light Rail Line included • Dwell Times: • 15-25 sec. per bus • 30-50 sec. for Central Light Rail

  31. Central Light Rail Line

  32. Result – Comprehensive Downtown Baltimore Model

  33. Model Calibration Techniques

  34. Model Calibration Techniques • Calibration Standards: • Within 10% of counted link volumes • Within 20% of Travel Times

  35. Model Calibration Techniques • Travel Times calculated in field to mimic bus movements • Travel Times in model extracted to reflect field collection • For all vehicles, VISSIM expected to be higher • Buses comparable, less dwell time

  36. Model Parameters Adjusted • Driver Behavior Parameters • Safety Distance Adjustment • Lane Changing Behavior • “Saturation Flow Rate” – Additive and Multiplicative Distances • Some Links altered more than others • Creation of more than one parameter set per link type (Urban1, Urban2) • Account for more friction (e.g. Pratt St) • Minimum Lane Changing Distance (Connectors)

  37. Results • All 5 modeling teams met all calibration parameters set! • Higher confidence in model essential for alternatives analysis

  38. Alternatives Analysis

  39. Alternative Model Coding • Design Year of 2030 • All initial volume growth based on regional MPO travel demand model • Western Area models (Groups 1-3) utilized growth rate from MPO model • Downtown and East End account for parallel links and alternate routing by using TFlow Fuzzy Logic

  40. Use of TFlow Fuzzy • Existing VISSIM network routing and MPO growth used to develop base VISUM network • TFlow Fuzzy accounted for diversion – alternate one-way streets • Aided in redistribution of traffic in both Downtown and Fells Point

  41. Alternatives Considered • Shared Use BRT • Exclusive BRT • Exclusive LRT • Exclusive BRT with Downtown Bus Tunnel • Exclusive LRT with Downtown Tunnel

  42. Exclusive BRT – “Trench” Area

  43. Exclusive BRT – “Trench” Area

  44. Exclusive BRT – Baltimore / Lombard Transit Couplet

  45. Exclusive BRT – Baltimore / Lombard Transit Couplet

  46. Modeling Approach and Consistency • BRT/LRT Vehicle Characteristics consistent • Headways Based on Operating Plan for EIS • Dwell Times: 15-30 Sec. for BRT; 30-50 sec. for LRT • Vehicle Change and Clearance Intervals based on operating speeds and vehicle characteristics

  47. Modeling Approach and Consistency • Removal of existing travel lanes for exclusive transit lanes is anticipated to cause trip diversion • CBD, Fells Point – both are based on city grid • Use of T-Flow Fuzzy Logic in VISUM to estimate diversions

  48. Lessons Learned

  49. Lessons Learned • Establish a consistent approach at start of model process • Project controls / standards allow for easier and more accurate QA/QC review • Field verification a must for all elements • Understand how calibration data was collected • Regular communication between model teams

  50. Lessons Learned • VISUM / VISSIM integration utilizing TFlow Fuzzy ideally should be included early in model development • Take care in optimizing signal timings to minimize transit delay, vs. roadway corridor delay • Traffic signal timing plans should reflect how surface transit travels through the intersection • Communicate level of modeling effort early in the project