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URBAN ROADS

URBAN ROADS. Scope of Urban Roads. Urban/Suburban Road Segments  continuous permanent development along all or almost of its length, on at least one side of the road. Population at least 100.000

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URBAN ROADS

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  1. URBAN ROADS

  2. Scope of Urban Roads • Urban/Suburban Road Segments  continuous permanent development along all or almost of its length, on at least one side of the road. Population at least 100.000 • Interurban Road Segments  without continuous development on either side, such as restaurants, factories, or villages.

  3. Scope of Urban Roads • Urban Road Types • Two-lane two-way roads (2/2 UD) • Four-lane two-way roads • Undivided (i.e. no median) (4/2 UD) • Divided (i.e. with median) (4/2 D) • Six-lane two-way divide roads (6/2 D) • One-way roads (1-3/1)

  4. Scope of Urban Roads • Conditions: • Flat or essentially flat alignment • Straight or essentially straight horizontal alignment • On segments of roads which are not affected by queuing caused by intersections, nor by severe platooning downstream form signalised intersections

  5. Scope of Urban Roads • Road Segments: • Between and unaffected by signalised or major unsignalised intersections, and • Having similar characteristics along its length.

  6. Objective of Urban Roads • Design of urban roads should be selected with the aim to ensure that degree of saturation does not exceed an acceptable value (normally 0,75)

  7. Traffic Safety Considerations • Widening of the lane decreases the accident rates between 2-15% per meter widening (the high number refers to narrow roads). • Widening and improvement of shoulder surface conditions improves traffic safety, although to a smaller degree than lane widening

  8. Traffic Safety Considerations • A median reduces the accident rate with 30% • Median barriers (used when the space is insufficient to make a full median) reduce fatal and severe injury accidents with 10-30%, but increase damage only accidents.

  9. Urban Roads Performance Indicator • Degree of Saturation (≤ 0,75) • Level of Service (A – F) • Average Speed • Travel Time

  10. Level of Service Based on Average Speed

  11. STEP A-1: General Data • Date (day, month, year) and Handled by • Province • City name • City size (number of inhabitants) • Link number/road name • Segment between … or … • Segment code • Area type (COM, RES, RA/Frontage Road) • Length of segments • Road type (4/2 D, 4/2 UD, 2/2 UD, 2/1) • Time period • Case number

  12. STEP A-2: Geometric Conditions • Compass arrow showing North • Km-posts • Sketch of the horizontal alignment • Arrows identifying Direction 1 (North or East-bound) and Direction 2 (South or West-bound) • Names of the places • Major buildings • Intersections and entries/exits • Pavement markings

  13. STEP A-3: Traffic Conditions

  14. STEP A-3: Traffic Conditions

  15. STEP A-3: Traffic Conditions

  16. STEP A-4: Side Friction • Number of pedestrians passing along or crossing the road segment (0,5) /h,200m • Number of stopping vehicles and parking maneuvers (1,0) /h,200m • Number of motor vehicle entries and exists to/from roadside properties and side roads (0,7) /h,200m • Flow of slow-moving vehicles (bicycles, tricycles, horse-charts, oxcarts, tractors, etc. (0,4) /h

  17. Road Side Friction

  18. Road Side Friction

  19. Road Side Friction

  20. Road Side Friction

  21. STEP A-4: Side Friction

  22. STEP B-1: Analysis of Free-flow Speed • FV  free-flow speed for LV at actual conditions (kph) • FV0  Base free-flow speed for light vehicles (kph) • FVW Adjustment for effective carriageway width (km/h) • FFVSF  Adjustment factor for side friction conditions • FFVCS  Adjustment factor for city size

  23. STEP B-1: Analysis of Free-flow Speed

  24. STEP B-2: Free-flow Speed Adjustment FVW for Carriageway Width [Table B-2:1] • Four-lane divided (4/2 D) or One-way road • FVW = 8 WC – 28 • Four-lane undivided (4/2 UD) • FVW = 8 WC – 28 • Two-lane undivided (2/2 UD) • FVW = -0,0285 WC6 + 1,3687 WC5 - 27,066 WC4 + 281,74 WC3 -1628,4 WC2 + 4959,4 WC- 6230

  25. STEP B-2: Free-flow Speed Adjustment FVW for Carriageway Width [Table B-2:1] • Four-lane divided (4/2 D) or One-way road, and Four-lane undivided (4/2 UD)

  26. STEP B-2: Free-flow Speed Adjustment FVW for Carriageway Width [Table B-2:1] • Two-lane undivided (2/2 UD)

  27. STEP B-3: Free-flow Speed Adjustment Factor FFVSF for Side Friction • Road with shoulders • Table B-3:1 • Road with kerbs • Table B-3:2 • Adjustment factor FFVSF for six-lane roads • FFV6SF = 1 - 0,8 x (1 - FFV4SF)

  28. Roads with Shoulders

  29. Roads with Kerbs

  30. STEP B-4: Free-flow Speed Adjustment Factor FFVCS for City Size

  31. STEP B-5: Determination of Free-flow Speed for Actual Conditions • Free-flow speed for light vehicles (LV) • FV = (FV0 + FVW) x FFVSF x FFVCS • Free-flow speed for other vehicle types • FFV = FV0 – FV • FVHV = FVHV0 – FFV x FVHV0/FV0 • FVHV0  Table B-1:1

  32. STEP C-1: Base Capacity

  33. STEP C-2: Capacity Adjustment Factor FCW for Carriageway Width [Table C-2:1] • Four-lane divided (4/2 D) or One-way road • FCW = 6,25 WC – 2,75 • Four-lane undivided (4/2 UD) • FCW = 5,424528 WC – 1,92453 • Two-lane undivided (2/2 UD) • FCW = -12.424 WC6 + 76.838 WC5 – 195.332 WC4 + 260.873WC3 -192.689WC2 + 74.455WC– 11.715

  34. STEP C-2: Capacity Adjustment Factor FCW for Carriageway Width [Table C-2:1] • Four-lane divided (4/2 D) or One-way road

  35. STEP C-2: Capacity Adjustment Factor FCW for Carriageway Width [Table C-2:1] • Four-lane undivided (4/2 UD)

  36. STEP C-2: Capacity Adjustment Factor FCW for Carriageway Width [Table C-2:1] • Two-lane undivided (2/2 UD)

  37. STEP C-3: Capacity Adjustment Factor FCSP for Directional Split

  38. STEP C-4: Capacity Adjustment Factor FCSF for Side Friction • Road with shoulders • Table C-4:1 • Road with kerbs • Table C-4:2 • Adjustment factor FCSF for six-lane roads • FC6SF = 1 - 0,8 x (1 - FC4SF)

  39. STEP C-5: Capacity Adjustment Factor FCCS for City Size

  40. STEP C-6: Determination of Capacity for Actual Condition • C  Capacity (pcu/h) • C0 Base capacity (pcu/h) • FCW  Adjustment factor for carriageway width • FCSP  Adjustment factor for directional split • FCSF  Adjustment factor for side friction • FCCS  Adjustment factor for city size

  41. STEP D-1: Degree of Saturation • Q  Traffic flow (pcu/h) • Q  UR-2 (column 10 row 5 for undivided road) • Q  UR-2 (column 10 row 3 & 4 for each direction of travel on divided road) • C  Capacity (pcu/h) • C  UR-3 (column 16)

  42. STEP D-2: Speed and Travel Time • Determine the speed at actual traffic • Figure D-2:1 (two-lane undivided roads) • Figure D-2:2 (multi-lane and one-way roads) • Enter segment length (km) in column 24 UR-3 • Calculate average travel time (hour) for Light Vehicle

  43. STEP D-3: Evaluation of Traffic Performance • If DS > 0,75  revise calculations

  44. QUIZ

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