DistanceBased GDPs Guillermo Lulli Mike Ball U of
Distance-Based GDPs Guillermo Lulli, Mike Ball (U of MD) Bob Hoffman (Metron)
Distance-Based GDP z. Replaces Tier Approach z. GDP options are defined by drawing a circle around the airport and including all enclosed airports: y. All flights whose origin is within circle and whose arrival time is within GDP time period are included. z. Alternative programs obtained by increasing radius of circle.
Distance-based GDP vs Current Approach z. Flexibility: a wider range of possible solutions is available. z. Dominance: for each tier-based initiative, there is a corresponding distance-based initiative. z. Simplicity: the range of programs can be varied in a simple well-defined manner.
Airports considered z Atl 2 Nov 99 ft 16. 54 z Bos 2 Feb 00 ft 17. 02 z Dfw 10 Oct 98 ft 12. 48 z Dtw 6 Apr 00 ft 15. 14 z Ewr 27 Feb 00 ft 15. 19 z Iah 24 Feb 00 ft 17. 02 z Ord 3 Feb 00 ft 16. 51 z Phl 13 Aug 99 ft 18. 04 z Sfo 18 Aug 99 ft 13. 32 z Stl 19 Mar 99 ft 12. 58 19. 00 - 23. 00 aar 76 19. 00 - 00. 59 aar 40 14. 00 - 19. 59 aar 64 16. 00 - 21. 59 aar 36 18. 00 - 23. 59 aar 36 (3)/40 (3) 19. 00 - 00. 59 aar 40 18. 00 - 01. 59 aar 76 (2)/80 (6) 20. 00 - 01. 59 aar 40 16. 00 - 21. 59 aar 30 (3)/40 (3) 16. 00 - 21. 59 aar 32
Statistics used in our analysis: z z z z Total delay Airborne Holding delay Unrecoverable delay Affected flights Max delay Average delay Unnecessary delay: part of delay that is not necessary to meet the increased AAR, if the program is cancelled if OTD<CT<ETA else min{ CT- OTD, ETD-OTD, ETA-CT}, 0.
Bos 2 Feb 99 Distances vs Tiers Air Hold Avg Unrec Aff flights Max
Bos 2 Feb 99 Average delay vs Unrec. delay Unrec Avg.
Trading Off Avg Delay and Unrecov Delay z. Choose weights for each and consider: wgt 1 ave-delay + wgt 2 unr-delay z. Find distance that minimizes this weighted sum. z. Nominal values for this analysis: wgt 1 = 50 wgt 2 = 1
Bos 2 Feb 99 Weighted trade-off between Avg and Unrec. delay Unrec Trade-off Avg
Bos 2 Feb 99 Varying Tradeoff Weights 98 1
Bos 2 Feb 99 Avoiding Inefficient Solutions Unrec Efficient solutions
Efficient Initiatives: numerical example z. By varying distances inefficient initiatives can be avoided (Bos 2 Feb 99)
Consideration of Fairness: Delay Variability Unrec Delay Var Avg.
Stl 19 Mar 99 Distances vs Tiers Air Hold Delay 1 th 2 nd Max Avg Aff flight Unrec
Stl 19 Mar 99 Average delay vs Unrec. delay Avg Unrec
Stl 19 Mar 99 Weighted trade-off, Avg and Unrec. delay Trade-off Unrec Avg 2 nd Tier
Stl 19 Mar 99 Different Weighted trade-off 68 20
Stl 19 Mar 99 Avg delay vs Unrec. Delay & Delay Variability Unrec Delay Var Avg
Sfo 18 Aug 99 Distances vs 6 & 10 west 6 W 10 W Max Air Hold Unrec Avg Aff flights
Sfo 18 Aug 99 Weighted trade-off, Avg and Unrec. delay Trade-off Avg Unrec 6 W 10 W
Unrecoverable Delay ==> Unnecessary Delay unrecoverable delay = ground delay incurred by start time of program: if program canceled at start then all of this delay is unnecessary but none is recoverable What if program is canceled earlier or later than start time of program? ? unnecessary delay = ground delays applied to flights that push their CTAs past the program cancellation time expected unnecessary delay = expected value of unnecessary delay computed using distribution of possible cancellation time.
Sfo 18 Aug 99 Unnecessary delay (early cancellation time)
Sfo 18 Aug 99 Unnecessary delay (middle cancellation time)
Sfo 18 Aug 99 Unnecessary delay (late cancellation time)
Sfo 18 Aug 99 Unrecoverable vs expected Unnecessary delay Unrec Unnec
Sfo 18 Aug 99 Unrec. , Unnec. delay and weighted trade-off Unrec Unnec Avg weighted trade-off local minimum
Conclusions: z. Distance-based GDPs provider greater flexibility but are easy to understand manipulate. z. Flexible user interface could be developed to display and analyze options.
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