Analyses of Passenger and Baggage Flows in Airport Terminal Buildings
Analyses of Passenger and Baggage Flows in Airport Terminal Buildings
                                                                                                                      Passenger flows into departure lounges can be expressed by an S-shaped quartic curve.
                                                                                                                    The flow of passengers from the departure lounge into an airplane and from the airplane
                                                                                                                    into the lounge is nearly linear. Scheduling of arrivals of large aircraft at about the same
                                                                                                                    time will result in very high passenger flow rates in pier finger corridors during very short
                                                                                                                    intervals of time. Deterministic theory can be applied to passenger and baggage arrival
                                                                                                                    characteristics which in turn can be used to estimate space requirements for passengers in
                                                                                                                    baggage claim area.
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                                                                                                     the lounge, the maximum will occur at some time after U, i.e.,                              ©   b = 14    Passengers   per minute   (one door /
                                                                                                                                                                                                 ®   b=28      Passengers   per minute   (two doors)
                                                                                                     nearer to departure time. Models were developed for F(t)                                    ©   b=42      Passengers   per minute   (three doors)
                                                                                                     and G(t).                                                                                   ®   b =56     Passengers   per minute   (four doors)
                                                                                                       The model for F(t) was determined by observing the flow
                                                                                                     to the lounge. Passengers were counted as they arrived
                                                                                                     and their arrival time was recorded. This procedure was
                                                                                                     continued until departure time. Prior to developing the
                                                                                                     model, the number of passengers on each flight was normal-
                                                                                                     ized in terms of percent. This step served as the basis for
                                                                                                     using the model to predict the number of passengers arriving
                                                                                                     at any time t, if the total number of passengers to be boarding
                                                                                                     a given flight was known.
                                                                                                                                                                                            60       50         40       30       20         IO     5    O
                                                                                                        The data obtained were used in a least-squares regression                                            Minutes Before Departure
                                                                                                     analysis. It was found that the best fit, i.e., the curve having
                                                                                                     a minimum value of the sum of the squares of the deviations           Fig. 3    Departure lounge sizes for 300 passenger airplanes.
                                                                                                     of the theoretical points from the observed points, was a
                                                                                                     quartic curve of the form                                                An average capacity flow rate was calculated from the ob-
                                                                                                                                              2
                                                                                                                 ^(0 = GO + ait + a2t + a^ + a±t*                          served flights, and the value of b turned out to be 14. The
                                                                                                                                                                           final model for passenger flow into an aircraft was, therefore,
                                                                                                     where F(t) = percent of passengers boarding a flight, t =
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                                                                                                     minutes before departure, ao = —1.78, a\ — 0.72, 0,2 = —0.02,                                    Q(t) = U(t - tb)
                                                                                                     a3 = 0.0025, and a4 = -0.00003.                                       Ninety-nine percent confidence limits for the expected value
                                                                                                        The standard error of estimate of F(t) on t was found to be        and variance of the capacity flow rate were 12 < £ < 14 and
                                                                                                     <7 = 1.6. A chi-square test for goodness of fit of the curve          1.3 < o-2 < 17.8, respectively.
                                                                                                     to the data revealed that the fit was good with a probability            The models can be used to investigate the relationship
                                                                                                     of 0.55. Detailed calculations are contained in a study by            between the number of aircraft doors, the time before de-
                                                                                                     Paullin.1 (60-0 is used as abscissa in Figs. 2, 3, and 4.             parture that these doors are opened, and the size of the de-
                                                                                                        The model for G(t), the flow into the airplane, was developed      parture lounge. Tradeoffs in time and space can be analyzed
                                                                                                     by observing passenger flow through the jetway and aircraft           and decisions formulated regarding future loading procedures.
                                                                                                     door. A regular pattern was evident, in that all or most of              Applications of the models are shown in Figs. 2, 3, and 4.
                                                                                                     the waiting passengers began queueing in the jetway as soon           From these illustrations, it is evident that the size of a de-
                                                                                                     as the boarding announcement was made. The queue lasted               parture lounge depends on 1) the size of the aircraft, 2) the
                                                                                                     until waiting passengers were boarded, at which time the              number of available entry doors into the aircraft, 3) the
                                                                                                     flow into the aircraft reduced to equal the flow of passengers        arrival pattern of passengers to the lounge, and 4) the time
                                                                                                     arriving at the lounge or G(t) — F(t).                                allowed for boarding passengers. Increasing the number of
                                                                                                        During the period of queueing in the jetway, flow rate into        entry doors into the aircraft permits a reduction in boarding
                                                                                                     the aircraft was maximum. The period of queueing varied               time; but if this is the goal, it is achieved at the expense of
                                                                                                     from 3 to 5 min, during which the flow rate was nearly con-           increasing the size of the departure lounge.
                                                                                                     stant. The model for the flow into the aircraft was, there-
                                                                                                     fore, selected as
                                                                                                                                                                            Additional Observations on Inflow and Outflow
                                                                                                                     G(t) = b(t -                 tb<t<t2                                   of Passengers
                                                                                                     where G(t) = number of passengers having boarded at time                 Since the completion of the study by Paullin,1 additional
                                                                                                     t,b = capacity flow rate, passengers/min, t = minutes before          observations were made on rates of flow of not only enplaning
                                                                                                     departure, tb = initial boarding time, and fa = time at which         but also of deplaning passengers.2 Passenger flow character-
                                                                                                     queue dissipates (see Fig. 1).                                        istics and estimated flow rates for loading passengers were
                                                                                                        It should be noted that G(t) is absolute, in terms of number       determined for two passenger handling strategies. The first
                                                                                                     of passengers and not in percent of passengers as is F(t). The        strategy was to load passengers without seat assignment and
                                                                                                     term G(t) is a function of the size and number of aircraft doors      the second was to load passengers with seat assignment. In
                                                                                                     available for loading and the interior configuration of the           addition, unloading rates were also observed. All passengers
                                                                                                     cabin.                                                                were loaded and unloaded through a jetway. A queue of
                                                                                                                                                                           passengers existed for all of the observed flights. The
                                                                                                                                                                                            60        50          40        30     20          IO
                                                                                                                      60    5O     4O      3O      2O       IO   O                                            Minutes Before Departure
                                                                                                                                 Minutes Before Departure
                                                                                                                                                                            Fig. 4    Departure lounge sizes for B-747, 500 passenger
                                                                                                         Fig. 2 Passenger arrivals at departure lounge.                                              capacity.
                                                                                                     448                                                            R. HORONJEFF                                                             J. AIRCRAFT
Passenger f/o
                                                                                                                                                                                                                            Baggageunloadarea
                                                                                                                                                                                                         bags
                                                                                                                                                                                                 Q passengers
                                                                                                     initial surge occurs and 2) the rate is higher for flights with                        Baggage Claim Area
                                                                                                     no seat assignment. With seat assignment, the average
                                                                                                     loading rate at 4 min was about 16 passengers/min, which is               Space requirements for baggage claim are an important
                                                                                                     not much different than the 14 passengers/min reported by              input in the design of airport terminal buildings. Space
                                                                                                     Paullin.1 With no seat assignment, however, the average                needs can be greatly influenced by the interrelationship of
                                                                                                     rate was about 20 passengers/min.                                      passenger and baggage arrival patterns at the baggage claim
                                                                                                        Of equal importance is the unloading rate, since the number         area. A deterministic queueing model was developed to re-
                                                                                                     of doors required for large aircraft could well be governed by         late the number of bags on a carousel to the arrival distribu-
                                                                                                     the time desired to empty rather than load an aircraft. Fig-           tion of passengers and baggage. The model was based on
                                                                                                                                                                            experimental data taken at San Francisco International Air-
                                                                                                                                                                            port.3 From these data, the following were developed:
                                                                                                                                                                             1) cumulative passenger arrivals at the baggage claim at
                                                                                                                                      Y2 = 11+17tf.
                                                                                                                                                                            time t = Ap(t), 2) cumulative bag arrivals at the carousel
                                                                                                                                                                            at time t = Ab(i), and 3) bags remaining unclaimed at select
                                                                                                                                                                             times after the start of baggage arrival. Time was measured
                                                                                                                                                      - A UAL5II-            from the instant an arriving flight began to disembark
                                                                                                                  Y, =24t,
                                                                                                                                                       ° UAL5I9
                                                                                                                                                       • UAL 521
                                                                                                                                                                            passengers.
                                                                                                                                                       o UAL 523
                                                                                                                                                                                The baggage claim system at San Francisco International
                                                                                                                                                                             Airport is schematically illustrated in Fig. 8. When the air-
                                                                                                                                                                             craft reaches its position on the ramp, personnel move a
                                                                                                                               Loading Time-minutes                          train of baggage trailers into position at the aircraft. For
                                                                                                     Fig. 6 Cumulative number of enplaned passengers
                                                                                                                                                                             containerized aircraft, containers are lowered onto gondola
                                                                                                     (passengers loading without seat assignment—Boeing 727).                trailers, which are then towed to the baggage unload area for
                                                                                                                                                                             unloading. For pit loaded aircraft, bags are unloaded, with
                                                                                                                                                                             the help of mechanized loading equipment, to flatbed trailers.
                                                                                                     ure 7 illustrates the typical results from several flights and
                                                                                                                                                                             Airport policy limits the number of trailers in tow to six, and
                                                                                                     indicates that the rate is fairly constant at about 36 passen-          the airlines frequently tow fewer than this number. Thus,
                                                                                                     gers/min.
                                                                                                                                                                             for large baggage loads, several trips may be required be-
                                                                                                       Paullin1 and Kaneko2 both point out that the rates of flow
                                                                                                                                                                             tween the aircraft and baggage unload area.
                                                                                                     are for the present size of doors. However, the doors on the               At the baggage unload area, ramp crews manually remove
                                                                                                     747 and other aircraft will be larger, so that flow rates will          bags from the trailers and place them on a conveyor belt
                                                                                                     probably be greater. At no time during the observations
                                                                                                                                                                             leading to a carousel. Maximum flow rate for the belt,
                                                                                                     were the jetways a constraint, either for loading or unloading.
                                                                                                                                                                             basedjon the capacity of the carousel to accept bags without
                                                                                                       There are many factors that can affect passenger flow                 clogging, is approximately 40 bags/mm. The unloading
                                                                                                     rates into an aircraft. Unfortunately, there was no oppor-
                                                                                                                                                                             rate for one man varies from 10-15 bags/mm. Thus, the
                                                                                                     tunity to study all of them, but they are listed below in the
                                                                                                                                                                             delivery rate can be very dependent on the size of the crew
                                                                                                     event continuing studies are made. These factors are as                 offloading baggage.
                                                                                                     follows: 1) width of jetway, 2) aircraft entry door width,
                                                                                                     3), type of service rendered at aircraft door (collect gate
                                                                                                                                                                                                 <f        6   8    /   0    /   2   /   4        16
                                                                                                                                                                                                      Time in Minutes After Aircraft Block Time
                                                                                                                              Unloading Time - minutes
                                                                                                                                                                            Fig. 9 Application of analysis to data of flight AA 225,
                                                                                                           Fig. 7 Cumulative number of deplaned passengers.                                      July 28, 1967.
                                                                                                     SEPT.-OCT. 1969                                                   PASSENGER AND BAGGAGE FLOWS                                                                              449
                                                                                                                               6         8        IO    12        14        16        18                4     6         8      IO         12     14      16      18        20
                                                                                                                        Time in Minutes After Aircraft Block Time                                                  Time in Minutes After Aircraft Block Time
                                                                                                     Fig. 10 Application of analysis to data of flight TWA 41,                              Fig. 12 Analysis of baggage requirements for a flight with
                                                                                                                                 July 20, 1967.                                             200 passengers and 400 bags at 40 bags/min delivery rate—
                                                                                                                                                                                                                 delayed delivery.
                                                                                                        Flights known to have large passenger and baggage load-
                                                                                                     ings were selected for analysis. The structure of the analysis                           To compute Wi, the following logic was used. There is
                                                                                                     is shown in Fig. 9. Knowing Ap(t), the probability dis-                                valid reason to assume that the arrival time of a bag Tb and
                                                                                                     tribution of a passenger arriving at the baggage claim area                            the arrival time of the passenger who seeks his bag TP are
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                                                                                                     Fp(t) = Ap(t)/Np < 1, where Np is the total number of                                  independent random variables. The time at which both
                                                                                                     arriving passengers. Knowing Ab(t), the probability dis-                               passenger and his bag have arrived at the carousel is Tp,b =
                                                                                                     tribution of a bag arriving at the carousel is Fb(t) = Ab(t)/Nb                        max (Tp,Tb), and the probability distribution function of
                                                                                                      < I , where Nb = total number of bags. Since the bags                                 Tp<b is then Fp,b(t) .= Fp(t)Fb(t) which is the probability that
                                                                                                     remaining on the carousel were counted for select times, the                           both the passenger and his bag arrive at the carousel at time
                                                                                                     expression for the cumulative number of bags removed from                              t. The average waiting time Wi is the area between the two
                                                                                                     the carousel at time t, Db(f), equals Ab(t) minus bags on carou-                       curves Fb(t) and Fp(i)Fb(t), which is
                                                                                                     sel at time t. Then the probability distribution of a bag re-
                                                                                                     moved from the carousel is Fd(t) = Db(t)/Nb < 1. At any                                                         \l* [Fb(t) - FP(t)Fb(t)]dt
                                                                                                      time t, the total number of bags remaining on the carousel
                                                                                                     Qb(t) is Nb[Fb(t) - Fd(t)], where Nb = total number of bags
                                                                                                      on a flight. This total should not be much larger than the
                                                                                                      capacity of the carousel, which at San Francisco was about
                                                                                                      80 bags (one-row deep—25.5 ft in diameter—circumference
                                                                                                      80ft).
                                                                                                         The average waiting time W for a bag to remain on a carou-
                                                                                                      sel is the area between the two curves Fb(t) and F(i(i), which
                                                                                                      is equal to
                                                                                                                                       ','' Fb(t)Fd(t)dt
                                                                                                                                                                                                        4      6         8      10        12      14      16      18       2O
                                                                                                     where ti = arrival time of the first bag and ti is the last bag
                                                                                                                                                                                                                   Time in Minutes After Aircraft Block Time
                                                                                                     to be claimed. W is the shaded area shown in Fig. 9 multi-
                                                                                                     plied by the total number of bags Nb. This average waiting                             Fig. 13 Analysis of baggage requirements for a flight
                                                                                                     time is the sum of two time periods W\ and Wz- The first                               with 200 passengers and 400 bags at 30 bags/min de-
                                                                                                     period W\ is the average waiting time when the bag arrives                                                  livery rate.
                                                                                                     at the carousel first and must wait for the arrival of the
                                                                                                     passengers and Wz is the average waiting time for the passen-                             The average waiting time Wz was determined experimen-
                                                                                                     ger to remove the bag from the carousel, assuming that both                            tally. A reasonable estimate of W^ would be one-half the
                                                                                                     passenger and bag are at the carousel. Clearly, W\ would                               time for the carousel to make one revolution, this being
                                                                                                     be equal to zero if all passengers arrived before the first bag                        J min at San Francisco. This estimate checked closely with
                                                                                                     arrived. If the passenger is at a certain position along the                           experimental data for flights with few passengers and bags,
                                                                                                      circumference of the carousel, waiting for his bag and the                            but for heavily loaded flights the value of Wi was closer
                                                                                                      bag is at the mouth of the carousel, Wz would be the average                          to 1 min.
                                                                                                      time taken for the bag to travel from the mouth of the carousel                          In summary, the mechanics of the analysis are as follows:
                                                                                                      to the location of the passenger and W\ is equal to zero.                              determine Fp(t) and Fb(t) experimentally. Compute FP(t)-
                                                                                                                                                                                             Fb(t) and then displace this line by an average value of
                                                                                                                                                                                             Wi(%-l min) and obtain Fd(t).
                                                                                                                                                                                               To verify the accuracy of the analysis, compare the com-
                                                                                                                                                                                             puted Fd(t) with the observed Fd(t) as shown in Figs. 9 and
                                                                                                                                                                                             10. Figure 9 illustrates the application to a specific flight,
                                                                                                                                                                                             AA225, and Fig. 10 the application to TWA Flight 41.
                                                                                                                                                                                               Figures 11, 12, and 13 show some applications of the anal-
                                                                                                                                                                                             ysis in comparing strategies for baggage delivery. In each
                                                                                                                                                                                                                                                                Aircraft
                                                                                                                        6          8         IO    12        14        16        18    2O               Terminal     Pier finger corridor                      — Gates
                                                                                                                                                                                                        Building
                                                                                                                            Time in Minutes After Aircraft Block Time
                                                                                                                                               V^  ^H 00po/
                                                                                                                                                   • Passe
                                                                                                                                                                                                    DC-8
                                                                                                                                                                                                    B-727
                                                                                                                                                                                                    B-727
                                                                                                                                                                                                                      1
                                                                                                                                                                                                                      1
                                                                                                                                                                                                                      1
                                                                                                                                                                                                                                        100
                                                                                                                                                                                                                                         76
                                                                                                                                                                                                                                         76
                                                                                                                                                                                                                                                    1705
                                                                                                                                                                                                                                                    1730(0)
                                                                                                                                                                                                                                                    1745
                                                                                                                                                                                                                                                                &
                                                                                                                                                                                                                                                                         1830
                                                                                                                                                                                                                                                                         1800
                                                                                                                                                                                                                                                                         1900
                                                                                                                                                                                                    B-727             1                  76         1745                 1830
                                                                                                                                                TO AIRCRAFT
                                                                                                                                                                                                    DC-8              1                 100         1755                 1855
                                                                                                                                                                                                    DC-8              1                 100         1755                 1855
                                                                                                                       Fig. 15          Passenger flow model.                                       B-727             1                  76         1800                 l820(T)a
                                                                                                                                                                                                    DC-8              1                 100         1800                 1900
                                                                                                     case, Fp(t) is based on a United Air Lines DC-8-61 with 200                                    DC-8              1                 100         1805                 1855
                                                                                                     passengers, and Wi is equal to 1 min.                                                          B-727             1                  76         1810                 1900
                                                                                                                                                                                                    DC-8              1                 100         1815                 1930
                                                                                                       The comparison of Figs. 14 and 15 shows the effect of the                                    B-747             4                 312         1815                 1900
                                                                                                     start of delivery time on bag storage requirements. In each                                    B-727             1                  76         1830                 1915
                                                                                                     case, delivery rate is 40 bags/min, the maximum rate for                                       B-727             1                  76         1840                 1935
                                                                                                     existing carousels. Note that for a strategy of early bag
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                                                                                                            16:4017:00 :20 :40 18:00 :20 .40 13:00 :20 *0                          21:00                         10    20   X      40    50    60   TO     dO       9O    /OO   IrO   J2O
                                                                                                                                            Time of Day
                                                                                                           Fig. 16         Scheduled aircraft gate occupancy.                                            Fig. 17      Flow of people in pier finger corridor.
                                                                                                     SEPT.-OCT. 1969                               PASSENGER AND BAGGAGE FLOWS                                                       451
                                                                                                     departure times from the gates are the same as opening the             The model has been made sufficiently flexible to accept
                                                                                                     doors to arrivals and closing doors for departures, 2) the          early or late aircraft arrivals and late departures (from
                                                                                                     flows of people in opposite directions do not interact signifi-     scheduled). In this way, one is able to examine the conse-
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                                                                                                     cantly, i.e., the corridor and the satellite area are wide enough   quences of not being on schedule on 1) passenger flows and
                                                                                                     so that free flow can occur in each direction, and 3) the time      2) delay to passengers due to lack of available gate positions.
                                                                                                     to walk from any jetway or departure lounge to the entrance         It was assumed that arrivals could be as early as 10 min and
                                                                                                     of the corridor is the same for all gates.                          as late as 20 min, and that between these two extremes the
                                                                                                        In developing the simulation model, the generation of flow       probability of such an occurrence was uniformly distributed
                                                                                                     in the pier ringer was assumed as follows.                          (equal probability). Minimum service times were obtained
                                                                                                                                                                         for several types of aircraft, and these were applied to the
                                                                                                     Generation of Departing Passengers and Departure                    late arrivals whenever the lateness was sufficient to delay
                                                                                                                                                                         the scheduled departure time.
                                                                                                     Visitors (DEPGEN)                                                      To illustrate the application of the model, a hypothetical
                                                                                                       1) Departing passengers are assumed to arrive at the              case was investigated. Given the following schedules (Fig.
                                                                                                     departure lounge in accordance with the investigation made          16 and Table 1), aircraft load factors, number of jetways,
                                                                                                     by R. Paullin described earlier in this paper1 and by Paullin       and number of visitors, and assuming that the aircraft are all
                                                                                                     and Horonjeff. 5                                                    on time, what would the people flow be at the entrance of the
                                                                                                       2) Departure visitors are assumed to accompany departing
                                                                                                                                                                         corridor to the satellite?
                                                                                                                                                                            It was assumed that for this particular application there
                                                                                                     passengers.
                                                                                                                                                                         were -f- visitors for each passenger. The results of the simula-
                                                                                                       3) Departure visitors are assumed to leave the departure
                                                                                                                                                                         tion are shown on Fig. 17.
                                                                                                     area in accordance with the S-shaped cumulative curve de-
                                                                                                     veloped by R. Paullin1 but compressed in time to a total of
                                                                                                                                                                                                  References
                                                                                                     10 min. It was also assumed that the first visitor leaves the         1
                                                                                                     satellite 5 min before the departure of the aircraft.                    Paullin, R. L., "Passenger Flow at Departure Lounges/'
                                                                                                                                                                         Graduate Report, Institute of Transportation and Traffic Engi-
                                                                                                     Generation of arriving passengers and arrival                       neering, Univ. of California, Berkeley, July 1966.
                                                                                                                                                                            2
                                                                                                     greeters (ARGEN)                                                         Kaneko, E. T., "Passenger Enplaning and Deplaning Char-
                                                                                                                                                                         acteristics/' Graduate Report, Institute of Transportation and
                                                                                                        1) Arriving passengers are assumed to exit from the air-         Traffic Engineering, Univ. of California, Berkeley, Aug. 1967.
                                                                                                                                                                            3
                                                                                                     port at a constant rate for each jetway (aircraft flow) based            Barbo, W. A., "The Use of Queueing Models in Design of
                                                                                                     on a study by Kaneko and others2 and leave the satellite            Baggage Claim Areas at Airports/' Graduate Report, Institute
                                                                                                     at this rate.                                                       of Transportation and Traffic Engineering, Univ. of California,
                                                                                                       2) Arrival greeters are assumed to accompany arriving             Berkeley, Sept. 1967.
                                                                                                                                                                            4
                                                                                                     passengers when leaving the satellite.                                   Smith, E. E., "Simulation of Passenger Flows in Pier Fin-
                                                                                                                                                                         gers," Graduate Report, Institute of Transportation and Traffic
                                                                                                       3) Arrival greeters are assumed to arrive at the satellite        Engineering, Univ. of California, Berkeley, Aug. 1968.
                                                                                                     with a distribution similar to the departure passengers but           5
                                                                                                                                                                              Paullin, R. L. and Horonjeff, R., "Sizing of Departure
                                                                                                     compressed in time to a maximum of 15 min.                          Lounges in Airport Terminal Buildings/' Proceedings ASCE-
                                                                                                        It was also assumed that the last greeter arrived at^the         AOCI Specialty Conference, Houston, Texas, April 10-14,
                                                                                                     same time as the aircraft.                                          1967.