Technical Appendix to Air Demand in a Dynamic Competitive Context with the Automobile (2019) / Chapter Skim
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Pages 98-108
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From page 99... ...
99 Air Level of Service The research team tested linear and log structures for frequency of flights and found that the log structure best fit the data, particularly with separate coefficients for direct flights and indirect flights. Demographics The research team applied demographic shifts to the car constant in the model.
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From page 100... ...
100 standard error. As a rule of thumb, robust t-ratios with an absolute value of less than two are not significantly different from zero.
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101 Shift for Denver (DEN) 0.7367 11.79 0.9584 8.79 0.6669 8.37 2.1049 1.85 The model also includes shifts on the air constant for all the large departure airports included in the study.
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From page 102... ...
102 Two or more unemployed adults in household 0.2788 2.89 0.4214 2.11 0.2539 2.21 1.2246 n/a Party size is one -0.5557 -6.13 -0.1427 -0.89 -0.3549 -2.83 -0.9236 n/a Trip is a day trip (vs. 1–6 nights away)
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From page 103... ...
103 TABLE 10-3: LEVEL-OF-SERVICE COEFFICIENTS FOR THE MNL MODELS ATTRIBUTE ALL PURPOSES BUSINESS ONLY LEISURE ONLY ALL PURPOSES (MMNL) ONLY EST ROBT EST ROBT EST ROBT MEAN SD Airfare -0.0038 -12.67 -0.0026 -6.50 -0.0055 -13.75 -0.0375 0.10 Gas cost for trip to airport -0.0461 -5.12 -0.0525 -3.43 -0.0448 -3.96 -0.3569 0.94 Parking cost at airport -0.0129 -8.60 -0.0112 -4.00 -0.0149 -7.84 -0.0537 0.22 Gas cost for driving trip -0.0059 -6.56 -0.0016 -1.00 -0.0089 -8.90 -0.0772 0.22 Rental car cost for driving trip -0.0012 -1.09 -0.0018 -1.20 -0.0026 -1.30 -0.1517 1.39 Flight time -0.0027 -13.50 -0.0028 -9.33 -0.0029 -9.67 -0.0154 0.03 Time to access airport -0.0239 -29.88 -0.02 -15.38 -0.0269 -24.45 -0.0795 0.16 Driving time -0.002 -20.00 -0.0018 -9.00 -0.0023 -23.00 -0.0372 0.33 Log of frequency for direct flights 0.148 10.14 0.1507 6.58 0.1471 7.66 0.1534 0.29 Log of frequency for connecting flights 0.1615 11.62 0.1341 6.42 0.1698 9.18 0.1735 0.13 Driving trip made by an autonomous vehicle -0.0588 -1.65 0.0711 1.02 -0.1316 -3.03 -0.2833 2.78 One-stop flight (vs.
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From page 104... ...
104 medians, means, and standard deviations. The MMNL model results show extensive heterogeneity for in-vehicle time for both car and air, and the long tail of the lognormal distribution increases the mean compared to the median for these two valuations.
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From page 105... ...
105 WTP for one additional flight per day for direct flights at base freq. of 10 3.89 5.80 2.67 0.60 6.85 53.36 WTP for one additional flight per day for connecting flights at base freq.
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From page 106... ...
106 MIXED MULTINOMIAL LOGIT MODEL APPLICATION AND SIMULATION To demonstrate how the choice models can be used to answer questions about changes in level of service, the research team applied the MMNL model to the ACRP survey data using a sample enumeration technique. This technique applies the model to each record of the dataset using the origin and destination of the reference trip as well as other variables associated with that trip, including party size, length of stay, access mode to each airport and demographics.
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From page 107... ...
107 The Base Scenario shows a mode share of 48.9% air and 51.1% car. Of those that fly 84% fly out of a large hub airport while 16% flight out of a smaller or medium airport.
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From page 108... ...
108 These five early scenarios present an example of the types of simulation that can be done by applying the model and can serve as a jumping off point for discussion and for further, more rigorous, applications of the model.
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