Project For Transportation Reform Lunch

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Project For Transportation Reform Lunch

  1. 1. Florida Green Book & New TND Street Design Chapter<br />Billy Hattaway, PE, CNU<br />
  2. 2. “The Perfect Storm”<br /><ul><li>Federal Highway Trust Fund – in the red as of September 2008.
  3. 3. State transportation revenues also in big trouble….FDOT deferred $7 billion in projects
  4. 4. Climate change
  5. 5. Development on hold</li></li></ul><li>“The solution of the traffic problem is to be sought not so much by wider streets as by proper plan of the town.”<br />John Nolen, 1926<br />
  6. 6. AASHTO “Green book”<br /><ul><li> Adopted by state DOT’s
  7. 7. Reflects consensus of states on what constitutes good design practice
  8. 8. Never intended to be used solely as a standard to base the design of every improvement on</li></li></ul><li>
  9. 9. Flexibility in Highway Design - FHWA<br /><ul><li>“… functional classification establishes the basic roadway cross section in terms of:
  10. 10. lane width
  11. 11. shoulder width and other major design features…”
  12. 12. “The flexibility available to a highway designer is considerably limited once a particular functional classification has been established.”</li></li></ul><li>FDOT Plans Preparation Manual<br />Based on AASHTO criteria <br /><ul><li> Florida roadways – focus on:
  13. 13. Higher speeds
  14. 14. Highway capacity
  15. 15. Functional classification
  16. 16. Rural & suburban</li></li></ul><li>A Typical State Arterial Highway<br />Miami, Fl<br />
  17. 17. FDOT “Green Book”<br />“Manual of Uniform Minimum Standards for the Design, Construction and Maintenance for Streets and Highways”<br /><ul><li>Where does it apply?
  18. 18. Local roads</li></li></ul><li>FDOT “Green Book”<br /><ul><li> Based on AASHTO “minimums”
  19. 19. County & City Roads – focus on:
  20. 20. Highway capacity
  21. 21. Functional classification
  22. 22. Rural & suburban development
  23. 23. Traffic calming & Residential Street (suburban) chapters added</li></li></ul><li>TND Chapter<br /><ul><li>Why is this chapter being included?
  24. 24. Local governments want to encourage TND development patterns
  25. 25. Context is needed to define when TND street design criteria is appropriate
  26. 26. Criteria will reduce liability for all parties</li></li></ul><li>Green Book Project Goals<br /><ul><li>“Traditional” and “Conventional” character defined anddifferentiated
  27. 27. Context and character for use of Traditional street design defined</li></li></ul><li>TND Chapter Content<br />AIntroduction – TNDvs CSD<br />BPlanning Criteria – Guiding principles<br />C Context – The Transect<br />DDefinitions – Teaching engineers a new language<br />ELand Use – Can’t get there without it<br />FNetworks – Power of the network<br />GThoroughfare Types – Functional class vs Movement<br />HDesign Principles – Guiding principles<br />ICross Section Elements – Defining the pieces<br />JTravelled Way - Designing the street<br />KIntersections - Focused on pedestrians<br />
  28. 28. The Context<br />
  29. 29. Size neighborhoods for a 5-minute walk<br />
  30. 30. Make blocks a walkablesize:<br />A fine grained network of streets & ammenities<br />Neighborhood Centers<br />Parks and Open Spaces<br />Civic Buildings<br />
  31. 31. Lane Width<br /><ul><li>The normal range of design lane width is 9-12’
  32. 32. Wider lanes are associated with higher speed roadways</li></li></ul><li>Lane Width<br /><ul><li>There is less direct evidence of a safety benefit associated with wider lanes in urban areas.
  33. 33. Lane widths substantially less than 12 feet are considered adequate for a wide range of volume, speed and other conditions.</li></li></ul><li>Driver Expectation<br />
  34. 34. Design Speed<br /><ul><li>Conventional practice is to design as high a speed as possible</li></ul>VS<br /><ul><li>Traditional practice is to design for the context and speed desired to support other modes</li></li></ul><li>Design Speed<br /><ul><li> Design speed is a selected speed used to establish geometric features of the street</li></ul>VS<br /><ul><li>Using the built environment to send the driver a clear message on how fast to drive</li></li></ul><li>Pedestrian Fatalities & Speed<br />
  35. 35.
  36. 36. Lane Width:<br />
  37. 37. Clear Zone:<br /><ul><li>An obstacle free area that permits the driver to safely return to the roadway or bring the vehicle to a safe controlled stop
  38. 38. Speed determines how much</li></li></ul><li>Clear Zone<br />
  39. 39. Horizontal<br />Clearance<br />
  40. 40. Horizontal Clearance<br /><ul><li>The focus of urban streets is provision for:
  41. 41. Pedestrians
  42. 42. Street furniture
  43. 43. Landscaping
  44. 44. In urban areas, 1.5’ minimum is for operational needs (car door conflicts), not safety.</li></li></ul><li>“Barrier Curb”<br />Curb has no re-directional capabilities except at speeds less than the lowest design speeds used on the State Highway System. <br />
  45. 45. Intersections<br /><ul><li>Driving through intersections is one of the most complex conditions drivers encounter
  46. 46. 50 percent of fatal and non-fatal injuries to pedestrians occur at or near intersections</li></li></ul><li>Conflicts at a Four-Way Intersection<br />
  47. 47. Intersection Safety<br /><ul><li>Hazardous intersections
  48. 48. High-volume
  49. 49. High-speed
  50. 50. Multilane
  51. 51. Complex signal phasing</li></li></ul><li>Typical State Road Intersection<br />
  52. 52.
  53. 53.
  54. 54.
  55. 55. Florida Green Book & New Urban Street Design<br />Billy Hattaway, PE, CNU bhattaway@vhb.com<br />Phone: 407.704.0782<br />

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