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Net speed calculator

Net speed calculator. Program. Input: Acceleration ( a ) & Deceleration rates ( d ) in ft/s2 Distance traveled ( L ) in feet Distance between intersections ( D i ) in feet Speed Limit ( S lim ) in mph Average waiting time at an intersection ( T wait ) in seconds

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Net speed calculator

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  1. Net speed calculator

  2. Program • Input: • Acceleration (a) & Deceleration rates (d) in ft/s2 • Distance traveled (L) in feet • Distance between intersections (Di) in feet • Speed Limit (Slim) in mph • Average waiting time at an intersection (Twait) in seconds • Time step (h) in seconds (can be change in the program, but it isn’t ask to the user)

  3. Output: • Net Speed (Snet) • Time-Distance-Speed Matrix • Time-Space Diagram

  4. Run the program • Set the Current Directory in the right folder (the one that contains MainProgram4 and the other functions) • Open MainProgram4 • Run MainProgram4

  5. Illustration of Inputs and Outputs Matlab Command Window Time-Space Diagram

  6. Time-Space Diagram Detail Instantaneous Speed and Distance traveled are recorded at each time step during non constant speed phases (acceleration end deceleration phases), otherwise (when the speed limit is reached, or when the vehicle is stopped), they are recorded only at the beginning and end of the phase) h=0.05 sec

  7. Assumptions • Constant Acceleration/Deceleration • Intersections are equidistant • Same waiting time at every intersection (uncoordinated intersections) • No queuing space

  8. Acceleration/Deceleration rates A lot of different values. But Deceleration rate always > Acceleration rate (cf. hypotheses)

  9. Distance between intersection: • Portland downtown: 1intersection every 260ft • Phoenix downtown: 1intersection every 385ft • Tucson: 440ft • Los Angeles downtown N-S: 1intersection every 660ft (410ft E-W) • Manhattan E-W: 1intersection every 880ft (255ft N-S) • Lyon downtown (2è): 1intersection every 185ft *Distances calculated with Google Earth

  10. Reference situation: Snet= 11.3621 ft/s = 7.75 mph Time-Space Diagram

  11. Time-Space Diagram for different situations Snet1= 6.61 mph Snet2= 7.15 mph Snet3= 9.48 mph Snet4= 9.78

  12. Time-Space Diagram for different situations a1, d1, Di1, Slim2 Snet= 6.63 mph ~ Snet1= 6.61 mph An increase in the Speed Limit (from 25mph to 45mph) doesn’t change the Net Speed much with Di1 (260), a1 and d1 (6 and -6.5 ft/s2), because the maximum speed that can be reached is around 26.8 mph. ~26.8 mph

  13. Net Speed and Posted Speed Limit 34.1 mph 49.5 mph

  14. Net Speed and Posted Speed Limit 26.8mph

  15. Net Speed and Di

  16. Net Speed and acceleration/deceleration rates

  17. Net speed and waiting time

  18. Limitations • In practice: variable waiting time, coordinate intersections • Non constant acceleration/deceleration: Acceleration 1st gear Acceleration vsspeed for different gears schema 2nd gear 3rd gear 4th gear 5th gear Speed

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