It was assumed that the distribution shape remains

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Unformatted text preview: d using IAT Distribution with the Actual Average IATs Number of vehicles per Hour 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 Driving Lane Passing Lane Average Average Average Average IAT IAT IAT for Fit IAT for based Correction based Correction Distribution Factor Distribution Factor on on (sec) (sec) Volume Volume (sec) (sec) 68.62 72.00 1.05 34.56 36.00 1.04 22.93 24.00 1.05 23.21 24.00 1.03 17.27 18.00 1.04 17.53 18.00 1.03 13.88 14.40 1.04 14.13 14.40 1.02 11.61 12.00 1.03 11.86 12.00 1.01 10.00 10.29 1.03 10.24 10.29 1.00 8.78 9.00 1.02 9.02 9.00 1.00 7.84 8.00 1.02 8.07 8.00 0.99 7.09 7.20 1.02 7.32 7.20 0.98 6.47 6.55 1.01 6.70 6.55 0.98 5.95 6.00 1.01 6.18 6.00 0.97 5.52 5.54 1.00 5.75 5.54 0.96 5.15 5.14 1.00 5.37 5.14 0.96 4.82 4.80 1.00 4.54 4.50 0.99 The IATs for the number of vehicles which are not listed in the tables, linear interpolation is used to calculate the IATs. 35 Table 8: Corrected IATs in Seconds based on Hyperbolic Formulae Developed for Driving Lane (Min 184 vehicles/hour, Max 782 vehicles/hour) Number of Vehicles per hour 150 200 250 300 350 400 450 500 550 600 650 700 750 800 Cumulative Percentage 0% 1% 2% 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99% 100% 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 1.37 1.15 1.02 0.93 0.87 0.82 0.78 0.75 0.73 0.70 0.68 0.67 0.65 0.64 1.87 1.54 1.34 1.21 1.11 1.04 0.98 0.94 0.90 0.87 0.84 0.82 0.80 0.78 2.23 1.87 1.66 1.52 1.41 1.33 1.27 1.22 1.18 1.14 1.11 1.09 1.06 1.04 4.02 3.19 2.69 2.35 2.11 1.93 1.79 1.68 1.59 1.51 1.44 1.38 1.33 1.29 6.88 5.30 4.35 3.72 3.27 2.93 2.66 2.45 2.27 2.13 2.00 1.90 1.81 1.73 9.44 7.22 5.89 5.00 4.36 3.89 3.51 3.22 2.97 2.77 2.60 2.45 2.32 2.20 12.58 9.57 7.76 6.56 5.70 5.05 4.55 4.14 3.81 3.54 3.30 3.10 2.93 2.78 16.80 12.70 10.23 8.59 7.42 6.54 5.85 5.30 4.85 4.48 4.16 3.89 3.65 3.45 22.65 16.98 13.58 11.31 9.69 8.48 7.53 6.78 6.16 5.64 5.21 4.83 4.51 4.23 29.83 22.24 17.69 14.65 12.49 10.86 9.60 8.59 7.76 7.07 6.49 5.99 5.56 5.18 37.63 28.11 22.40 18.59 15.87 13.83 12.24 10.97 9.94 9.07 8.34 7.72 7.17 6.70 52.79 39.38 31.33 25.97 22.14 19.27 17.03 15.25 13.79 12.57 11.54 10.66 9.90 9.23 73.31 54.15 42.66 35.01 29.54 25.45 22.27 19.73 17.65 15.92 14.46 13.21 12.12 11.18 83.68 62.39 49.62 41.11 35.03 30.47 26.93 24.09 21.78 19.85 18.21 16.81 15.60 14.54 90.51 67.81 54.20 45.12 38.64 33.77 29.99 26.97 24.49 22.43 20.68 19.19 17.89 16.76 100.82 76.95 62.61 53.05 46.21 41.08 37.08 33.88 31.25 29.06 27.21 25.61 24.23 23.01 36 Table 9: Corrected IATs in Seconds based on Hyperbolic Formulae Developed for Passing Lane (Min 66 vehicles/hour, Max 666 vehicles/hour) Number of Vehicles per hour 50 100 150 200 250 300 350 400 450 500 550 600 650 700 Cumulative Percentage 0% 1% 2% 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 98% 99% 100% 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.76 0.62 0.58 0.55 0.53 0.52 0.51 0.50 0.50 0.49 0.49 0.48 0.48 0.47 1.16 0.85 0.74 0.69 0.65 0.63 0.61 0.59 0.58 0.57 0.56 0.55 0.55 0.54 1.82 1.20 1.00 0.89 0.82 0.78 0.75 0.72 0.70 0.68 0.68 0.65 0.64 0.63 3.08 1.84 1.43 1.22 1.09 1.00 0.94 0.89 0.85 0.82 0.80 0.77 0.75 0.74 9.49 4.79 3.23 2.45 1.98 1.66 1.44 1.27 1.14 1.03 0.95 0.88 0.82 0.76 15.92 7.86 5.18 3.83 3.03 2.49 2.11 1.82 1.60 1.42 1.28 1.16 1.05 0.97 26.20 12.81 8.36 6.13 4.79 3.91 3.27 2.80 2.43 2.14 1.90 1.70 1.53 1.39 40.74 19.86 12.91 9.43 7.35 5.97 4.98 4.24 3.67 3.21 2.83 2.53 2.26 2.04 65.04 31.58 20.44 14.87 11.54 9.32 7.74 6.56 5.64 4.91 4.31 3.82 3.40 3.05 90.96 44.58 29.13 21.41 16.79 13.71 11.51 9.86 8.59 7.57 6.74 6.05 5.46 4.96 132.30 65.11 42.72 31.54 24.83 20.37 17.18 14.79 12.94 11.46 10.25 9.25 8.40 7.67 199.10 98.70 65.24 48.52 38.49 31.81 27.04 23.47 20.69 18.47 16.65 15.14 13.87 12.77 235.58 114.91 81.04 61.71 50.09 42.34 36.80 32.64 29.39 26.79 24.66 22.88 21.37 20.07 254.83 134.09 93.78 73.58 61.43 53.29 47.45 43.05 39.61 36.84 34.56 32.65 31.02 29.61 267.27 143.90 102.68 81.99 69.52 61.17 55.16 50.62 47.06 44.18 41.81 39.81 38.10 36.62 295.18 163.65 119.66 97.55 84.19 75.21 68.74 63.83 59.97 56.84 54.24 52.05 50.16 48.52 37 Validation results were created by entering in the observed hourly traffic count for the validation data and comparing the output generated by the spreadsheet to the actual observed cumulative IAT distribution generated from three periods of data previously set aside. In addition to the comparison of the generated IATs with the actual data, the fitting of the generated IATs were also compared with the mathematical distributions available in the literature for IAT calculation. May [24] in his Traffic Flow Fundamentals book, classified the time headway distributions (Inter-arrival Time Distributions) into; random headway state, constant headway state, and intermediate headway state. Negative exponential distribution is the mathematical distribution that represents the random inter-arrival times. In his study, May compared the field data with the negative exponential distribution. He found that negative exponential distribution does not reflect the actual data characteristics quite well. Negative exponential distribution was best for fitting at low flow levels...
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This document was uploaded on 02/26/2014 for the course E 515 at University of Louisiana at Lafayette.

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