2010-59
Role of schedule delays on
passengers’ choice of access modes:
A case of Japan’s international airport
Chikako Keumi Hideki Murakami

Role of schedule delays on passengers’ choice of access modes:
A case of Japan’s international airport
Chikako Keumia,*, Hideki Murakami baDepartment of Business Management and Accounting, Osaka Seikei College, Osaka, 533-0007, Japanb

Graduate School of Business, Kobe University, Kobe, 657-8501, Japan

Abstract
In this paper, we empirically studied passengers’ modal-choice behaviors to access an international hub airport fromlocal areas. Through the data collected by using stated preference method and constructing binomial logit model, we
found that passengers’ modal choices were affected by the level of service variables of access modes, such as travel
time, travel cost, waiting time at hub airports and scheduled delay cost. Furthermore, an increase in frequency would
reduce waiting time at hub airports. However, when passengers chose available access modes to hub airports inadvance provided that the departure time was fixed, they especially considered the timing of departure from home andthe timing of arrival at the airport (that is, convenience of schedule), as well as frequency of access modes.
We also calculated the value of scheduled delay. Based on the results of the value of scheduled delay, we proposed
the pricing methods to correspond to passengers’ various scheduling needs in the last section.
Keywords: Scheduling; Service frequency; Access mode choice; Hub airports; Stated preference; Binomial logit model* Corresponding author. Tel.: +81-6-6829-2891; fax: +81-6-6829-2749

E-mail address: keumi@osaka-seikei.ac.jp (C.Keumi)

or 4 flights per day. Such low frequencies may leave

1. Introduction
thetransfer passengers with long waiting times or highdeterminants of modal choice to access a hub airport

rescheduling costs at origins or hub airports. Whenfrom local areas. We adapted a binomial logit model

passengers have to stay at hub airports for as long aswith two alternatives, air and limousine, to find traveler

three or four hours due to low flight frequencies, thevaluations with data from a stated preference survey wesaved in-vehicle time might be offset by this longdesigned.

waiting time. In the case of a limousine bus, even it

In

this

study

we

empiricallyexamined

To collect the data, we picked Kansai Internationaltakes longer to access the hub airport than it takes when

Airport (KIX) as a hub airport and Takamatsu andtraveling by air, if passengers can arrive at a desired

Tokushima as local areas. KIX is the nearest

time due to relatively sufficient limousine bus departureinternational airport to both local areas. Currently, thetimes, travel by limousine bus will be more convenient

main access mode from Takamatsu and Tokushima tothan traveling by air. In this case, travelers would face

KIX is a limousine bus, which takes about 3.5 hours

the trade-off of long travel time or long waiting time.

from Takamatsu and about 2.75 hours from Tokushima.

This is a crucial point to consider when discussing

Until recently, commuting access flights to KIX werepassengers’ behavior when choosing their access mode

available from both local airports. It took about 30

to hub airports.

minutes to access KIX from both airports by jet.

Generally, passengers determine which international

Currently the resumption of jet services is pending due

flight to use at hub airports in advance, and the flightto their high operating costs.

departure time is fixed. Under this situation, they must

In considering passengers’ modal choices of access toconsider not just the frequency of a given access mode

hub airports, the authors of previous studies havebut also the arrival timing at a hub airport to transfer tofocused on in-vehicle time, travel cost, frequency andtheaccess time as main factors of choice, probably because

determinants of the selection of access mode to hubof lack of publicly available data of sufficient quality.

airports

However, what seems to be lacking is a consideration ofdecision-making process, we need not look at the“convenience of scheduling” from the demand side. If

frequencies of the access modes; examining the arrival

this factor is not present, it means that travelers cannot

timing of access modes at hub airports should be

realize their desired arrival time and departure time

sufficient.

internationalinflight.

reflecting

Therefore,
theactualtoexaminepassenger

because of the low frequencies or fixed time scheduling

The second issue is the difference in the value of totalof the services. In this paper we focused on two issues

travel time savings by departure time at home. Here,that are part of “convenience of scheduling“

total travel time is the accumulated time from departure

The first issue is arrival timing of access modes fortime at home to flight departure time at the hub airport.

international flights at hub airports. In this situation,

It is likely that passengers want to leave home at a time

flight frequency is important. However, in the case of airthat doesn’t require changing their lifestyle. For

travel, we cannot expect sufficient frequency of flights

example, many international flights at KIX depart atfrom local airports. From local areas, there are at most 3

around 10 a.m. To take these flights, passengers have toleave home in the early morning. From Takamatsu, forconvenience of scheduling as a service variable added toaccess to these flights, the only choice is a limousine bus

travel time and travel cost to influence airline demand.

departing at 4 a.m. Thus, passengers taking this form of

In prior research, only travel cost and travel timetransportation have to depart home much earlier thanincluding access time and egress time had been handledaccommodates their usual life style. To avoid missed

as a generalized cost in analyzing airline demand.

connections or changes to their life style, there are risk

Besides these costs, Douglas and Miller defined andaverters such as staying at a hotel near KIX the night

adopted scheduled delay (SD), that is, the difference

before a flight. In this case, considerable reschedulingbetween the preferred arrival time (PAT) travelers wantcost would be imposed on travelers. Therefore, we

and the actual arrival time scheduled in advance, as an

assume that the value of total travel time savings would

additional cost for travelers in their research. This study

vary based on whether passengers change their lifestyle

was significant because it revealed that the apparent

to access transportation.

level of fares was very high under a regulated airline

To better understand passengers’ behavior in choosing

market at that time, when SD cost was included inan access mode to hub airports from local areas, we felt

travelers’ generalized costs. Moreover, a remarkable

examining the above two issues concerning thecontribution of their study was to explicitly define andconvenience of scheduling were very meaningful. The

take into account this SD, in other words, convenience

main contribution of this study was that we examinedof scheduling in service variables, for the first time.

these two issues via a stated preference survey that weFollowing Douglas and Miller’s work, there were adesigned and administered. We also estimated that it

few empirical studies on airline demand. Morrison andwould be useful to discuss demand reaction in small

Winston (1985) substituted the SD variable in theirmarkets such as the one we focused on in this research.

mode choice model for mean service interval time forThis paper is organized as follows. We begin with avariousmodes.

MorrisonandWinston(1989)

brief review of prior studies dealing with convenience ofinvestigated airline users’ preference with an airline

scheduling by empirical research in airline markets inchoice model that included the SD variable. In this work,

Section 2. Next, in Section 3, we explain our researcha multinomial logit model was used with the SD

issues and methods, applying them to the Takamatsu andvariable calculated with real data and inserted into

Tokushima to KIX case. This is followed by a

Douglas and Miller’s formulation (equation). Morrisonpresentation of the stated preference survey weand Winston found that the value of SD was much lower

conducted and the stated preference data collected inthan the value of total travel time and transfer time.

Section 4. In Section 5, actual models are presented

A more recent study was that of Proussalogou andand empirical results are to be discussed. Concluding

Koppelman (1999), who examined a flight choice model

remarks are presented in Section 6.

with Stated preference (SP) data and conductedhypothetical experiments. In their research, SD was

2. Prior studies on convenience of scheduling in

defined as the absolute value of the difference presented

airline markets

by flight departure time on choice experiments andDouglas and Miller (1974) wrote the first study on

preferred departure time for respondents. They foundthat business travelers were more sensitive to SD thanMorrison and Winston (1985, 1989) used frequencies

were pleasure travelers, and the value of SD for businessdata as a substitute variable for the SD variable. This

travel was higher than that for pleasure travel.

process might not reflect real passengers’ decision

The most recent research was by Lijensen (2006),

making as part of scheduling behavior.

who examined a flight choice model with SP data in a

As an outcome from Rieveld and Brons (2001), when

hypothetical scenario. Lijensen supposed that thethere are seamless connecting flights in spite of lower

preferred arrival time (PAT) for travelers was an

frequencies, it is possible that passengers’ disutility

unknown parameter, so SD values were based on

based on SD cost might be kept at a low level. In thisestimatedtravelers’case, when passengers choose access modes to a hub

evaluation at each time, that is disutility, with a mixed

airport, they do not consider what frequencies the accesslogit model.

Lijensen separated SD into two parts,

modes have in a week or a day, but rather they considerscheduled delayed early (SDE) and scheduled delay latethat the desired arrival time of the access modes depends(SDL). SDE was defined as an earlier arrival than theon the departure time of the international flights they

estimated PAT, and SDL was defined as a later arrival

will take from hub airports.

PAT

valuesthat

described

than the estimated PAT. This work was the first in which

It is natural that the SD can be interpreted as

SED and SEL were explicitly taken into account inundesired additional time, that is to say as anempirical research using an airline demand model. It

opportunity cost. To evaluate the opportunity cost thatwas found that travelers were more averse to SDL thanpassengers pay, using the monetary value of time would

to SDE. This result was consistent with other travel

be more appropriate than using the frequency. In

demand research that included SDE and SDL.

considering these points when examining an access

Rieveld and Brons (2001) examined convenience ofmode choice model, it is most suitable to use

schedule at hub airports for travelers to adopt the SD

disaggregate data and include the SD variable as thedefinition in empirical analysis with data from majordifference of actual arrival time and desired arrival time.

European hub airports. They hypothesized that theinconvenience of waiting time at hub airports was not

3. Model approach and issues

simply affected by the number of flights. In general,

The aim of the present study was to gain insight into

London Heathrow and Paris Charles de Gaulle havethe demand for access modes to international hub

such high frequencies that the mean waiting time isairports from local areas. Given this aim, we examinedsupposed to be short. However, by using a schedulingan access modal choice model with data from a SP

ratio reflecting the inconvenience of waiting time at hub

survey we designed.

airports, they found that Amsterdam, with the lowest

To conduct our research, we picked two access modes

flight frequencies among European major hub airports,

to Kansai International Airport (KIX), that is, air andperformed better than did its competitors.

limousine bus. In SP survey, it is important for the

As mentioned above, although a few studies included

reliability of SP data that respondents can imagine a

the SD as a service variable, the methods used to define

concrete choice process. In Takamatsu and Tokushima,and set this variable in the models were not consistent.

the main access mode to KIX is currently a limousinebus; airline services accessing KIX were supplied in the

If the number of flight per day increase three to four,

past from Takamatsu and Tokushima airports. We chose

respondents in SP survey could not make the difference

to omit rail and ferry and auto as alternatives in ourof these questions clear. Moreover, since each passenger

survey. First, in considering the burden of answering SP

only needs a single trip, frequency in itself has noquestions, we assumed that it was appropriate to limit

meaning for them. Rather, we assume that connecting

the case so that passengers need not consider

times at hub airports will play a more important role fortransferring transportation modes on the way to KIX.

each passenger. Thus, this convenience of scheduling

Second, for simplicity to compare with alternatives, wevariable has to be defined as the difference between

described a situation in which the travel cost is only thepreferred arrival time (PAT) for respondents and theticket price. In the case of automobile travel, the travel

actual arrival time of access modes in the SP survey.

cost is comprised of at least petrol cost and parking cost,

Therefore, we designed the SP survey so thatand it is complicated to ask respondents to compare

respondents can answer in more realistic terms about the1

alternatives when including this option . Thus, we gavea choice of only two access modes, air and limousine
bus, and we dealt with a one-way trip to KIX.

modal choice situation.
When transferring at hub airports, passengers needconsiderable time for check-in and boarding. TheseIn this study we focused on two issues ofprocedure times vary by airport and airline. We also

“convenience of scheduling“. The first issue is arrival

assumed that the connecting times passengers neededtiming of access modes for international flights at hub

would vary based on passengers’ familiarity with airport

airports. The second issue is the difference of value of

use and the extent of delay for different access modes.

total travel time savings based on departure time fromFor example, passengers with a lot of experience taking

home.

business or leisure trips abroad might not need much

Regarding the first issue, because high frequency

time to transfer, because they are familiar withwould not be expected from local areas to hub airports,

procedures for transferring or traveling around hub

convenience of scheduling must not be excluded as a

airports.

service variable for access modes. And then, due to low

Of course, in going abroad, since travelers cannot

frequencies, such a question “three flights per day” asmiss connections at hub airports, the reliability of accessone service attribute, frequency, in SP survey doubt

modes is very important. To avoid missing connections,

whether this question reflects real traveler’s preferences.

it is quite likely that passengers plan their trips to allow
for delay or variability of arrival time, and passengers

1 It is quite likely that travel by automobile is an

who have experienced substantial delays might makeimportant alternative when passengers can carpool anduse the parking area at KIX. However, computing thetotal cost is complicated because the parking fee
depends on the length of travel, and the petrol cost andother costs of operating an auto would be included in thetravel cost. For these reasons we did not include
automobile travel in this survey. Actually, 75% of all
respondents in our survey in Takamatsu listed thelimousine bus as their main access mode to KIX in thepast five years.

large allowances for transferring. It is possible thatpassengers plan their trips not on the basis of actual
delay probabilities, but on what they perceive, based on
their personal experience, delays may be. Given this, it
has been difficult to measure passengers’ valuations orperceptions of reliability. Therefore, in our research, toavoid dealing with this reliability variable directly, wethat in the afternoon or evening. However, this researchassumed that travelers added extra time to the minimum

did not discuss in detail why the value of travel time wasconnecting time needed at hub airports. In addition, we

different according to the time of day. The authors did

assumed that this extra time varies according to traveler

point out the possibility that frequency, travel purpose or

and/or access mode. To overcome the difficulty of

traffic condition could influence the value of travel time.

differences in the transfer time that respondents need,

Also, Mackie et al. (2001) pointed out that the value of

we define PAT as the time each respondent needed andtravel time was different not only based on travelers’

answered in the SP survey for transferring at KIX withdemographic factors such as income or wage rate but

each mode, limousine and air. Thus, PAT has many

also on the time of day travel occurred. However,different values in each traveler, that is respondent insimilar to above research, this study did not examined

our survey and each mode.

precisely why the value of travel time would be different

We distinguished the SD variable with SDE and SDL.

based on the time of day.

When passengers arrive at hub airports earlier than they

We chose to focus on activities and time constraints

desired, this case is known as “scheduled delay early,”

as main factors in the difference of the value of timeor SDE. Scheduled delay has been defined as a measure

based on time of day. For example, when passengers useof convenience related to the difference between

flights that depart in the morning from KIX, they must

preferred arrival time (PAT) and actual scheduled arrival

leave home very early in the morning or stay overnighttime (AAT). That is, SDE=AAT-PAT. In the case of SDE,

in a hotel near KIX the night before. In fact, the peaktravelers have to wait at hub airports unnecessarily.

flight time for flying abroad from KIX is around 10 am.

When travelers arrive at hub airports later than theyThus, to connect during the peak time at KIX,

desired, this case is known as “scheduled delay late,” orpassengers must board the limousine bus departing at

SDL. That is, SDL=PAT-AAT. In this case, travelers feel

4:20 a.m. from JR Takamatsu station or at 5:05 a.m.

uneasy, since the longer SDL gets, the higher the risk offrom JR Tokushima station. Naturally this means they

missing their connection.

must leave their homes even earlier. It is clear why some

One main contribution of the present study was thatpeople would choose to stay at a hotel near KIX the

we examined an access modal choice model for a hub

night before going abroad. We cannot ignore or

airport with SD variables distinguished as SDE or SDL,

underestimate the additional cost (e.g. hotel fee) andand we clarified that the values given by theseopportunity cost (e.g. sleeping time) that arises as a

distinctions are different.

result of changes to passengers’ usual life style.

The second issue we focused on was the difference inGenerally speaking, activity time at home in thethe value of total travel time savings based on themorning, above all the time of waking up, might bedeparture time from home. In an earlier study, the MVA

fixed every day. In the case of leaving home earlier thanConsultancy (1987) estimated the value of time required

usual, travelers need to change their lifestyle so muchfor long-distance train use. The MVA study resultsthat scheduling cost cause to arise. On the other hand,showed that weekday passengers’ assessment of thewhen passengers can travel without changing theirvalue of travel time in the morning was 15% higher thanlifestyle, no additional scheduling costs are incurred.

Although total travel time is the same, it is possible thatfour levels in two patterns in both modes. The data ofthe value of time might be different in the former caseaccess time from home to bus stations and local airports

needed to change their lifestyle and latter without.

was obtained by asking respondents directly in ourIn this study, we examined the value of total travel

survey.

time savings by separating examples into flights to

To make choice sets, we used an orthogonal main

departing from KIX before noon and flights departing

effect fractional factorial model. By applying theafter that.

fractional factorial design, 16 different scenarios wereobtained that had to be evaluated by each respondent.
We set out two travel cases, a.m. departure and p.m.

4. SP design and data sources
Three service attributes (ticket price, in-vehicle time

departure from KIX, so that each respondent actuallyand connecting time) are selected for the two modes,

would have had to evaluate 36 different scenarios tolimousine and air. Ticket price and in-vehicle time arecover all possible combinations; however, evaluating soshown in Table 1 and connecting time in Table 2. To

many scenarios would be very demanding fordefine level of services, real information concerning

respondents, so we divided the scenarios into fourticket prices and times of the two modes was used as a

blocks randomly assigned to choice sets. Thus, eachbasis. Information about the level of services for the

respondent evaluated 4 choice scenarios in the case oflimousine bus was obtained from real information about

a.m. departure and p.m. departure at KIX. That is to say,

existing services. Thus, in this survey, there was noeach respondent evaluated 8 scenarios in each survey.

variation with respect to the level of ticket price andRespondents selected their travel purpose, business orin-vehicle time for limousine from Tokushima andleisure, at the beginning of the questionnaire based on

Takamatsu to KIX. In the case of air travel, as thetheir real experience or possibility of going abroad.

services are currently pending in both areas, real

We used our survey to collect responses aroundinformation wasn’t available. We obtained information

Takamatsu and Tokushima. For Tokushima, all data wasfrom past services on the same routes. Ticket price forcollected by a mail survey. For Takamatsu, in addition to

air travel was defined in four levels from Tokushima anda mail survey, questionnaires were handed out directly

Takamatsu to KIX. In-vehicle time for air has two levels

to travelers. The available sample was 952 completed

30, 45 minutes from Tokushima, 35, 50 minutes fromsurveys in Tokushima and 2617 completed surveys in

Takamatsu. As shown in Tabale1-2, connecting time has

Takamatsu.

Table 1Service attributes levels in the SP experimentTokushima
Takamatsu

Ticket price(one-way)
In-vehicle time (one-way)
Ticket price (one-way)
In-vehicle time (one-way)Air
9800, 7800, 5800, 3800 yen
30, 45 minutes
10000, 8000, 6000, 4000 yen
35, 50 minutes

Limousine bus
4000 yen
2.45 minutes
5000 yen
3.30 minutes

Table 2
Patterns of connecting times at KIX（hour.minute）
Air
a.m. departure at KIX
p.m. departure at KIX

Limousine bus

Pattern 1

1.40, 2.10, 3, .15

1.15, 2, 2.10, 2.40

Pattern 2
Pattern 1
Pattern 2

1, 1.40, 2.30, 3.50
1, 1.30, 2.15, 4.30
1.40, 1.50, 3.30, 3.40

1.30, 1.40, 1.50, 2
1.15, 2, 2.30, 3
1.40, 2.30, 2.50, 3.10

choosing the air travel option is as follows:

5. Demand model(5)

Variables in this model are shown in Table 3.

n
Pr n ( Air )  exp(V airn ) /(exp(V airn )  exp(Vbus))

The disutility of the traveler (U) under each

The criterion of optimality that is applied is thealternative (air and limousine bus) is as follows.

maximum

U air  V air   air(1)

Newton-Raphson method is used to maximize the

U bus  Vbus   bus(2)

likelihood function with respect to the parameter vector.

The disutility can be partitioned into a systematic

Expected signs are Access time<0, Travel time<0,component (V) and a random component (ε). The

likelihood

estimation

procedure.

The

Travel cost<0, SDE<0, SDL<0, Income>0.

parameters β are unknown. This study treats theindividual idiosyncrasies of taste as random under

6. Estimation results

random utility theory. The following linear specification

Table 4 shows the results of estimations using ourin the parameters is that used in estimation of the logit

model, separated by trip purpose (business or leisure)model:

for Takamatsu and Tokushima.

V air  Const  Income   1 Accesstime air   2 Traveltime air

On business trips, all variables were statistically  3Travel cos t air   4 SDE air   6 SDL air

significant and all the estimated signs were as expected.

V bus   1 Accesstime bus   2 Traveltime bus   3Travel cos t bus

We obtained a robust value of 0.27 on ρ2, which  4 SDE bus   6 SDL bus

indicates the degree of explanation for this model. The
value of the estimated parameter of IVT in this model(3)

was relatively higher than other parameters. Since it is

The following probabilistic function is estimated:
Pr ( Air )  Pr(V
n

n
air

V

n
bus



n
bus



n
air

possible that values of parameters would be considered) Pr( AirC  Income  1 ( AT  AT )   2 (TT  TT )as relative degrees of significance on the access mode 3 TC TC 4 (SDE  SDE )  5 (SDL  SDL )    )choice, this result indicates that business travelers take(4)much shorter IVT into account than do others whenPr(Air) is the dependent variable that indicates thechoosing the access mode.



n
air

n
air

n
bus



n
air

n
air

n
air

n
bus

n
bus

n
air

n
air

n
bus

n
bus

n
bus

n
air

For leisure trips, we did not obtain a robust value on

estimated probability of choosing air as a travel option,2

ρ ; its value, 0.18, was not bad to explain for this model.

where n is the individual.
Thus, the binary logit model arises from theassumption that

εbusn

n

Although the estimated sign of the IVT parameter wasand εair are independent andpositive, this was statistically insignificant. In the leisureidentically Gumbel distributed. The probability oftrip case, we could not obtain significant values with

respect to time variables such as access time and IVT.

the risk of missing connections at KIX because of the

Jara-Díaz (2000) suggested that variables relevant tohypothetical context in the SP questionnaire. Anothertime might be influenced more than cost by unobserved

possibility is that respondents might rate the reliability

variables that are difficult to set in models. This wouldof limousine and air travel higher in this area than thatbe one reason why we obtained such a result for leisureof modes in other areas. Moreover, when respondents

trips. That is, leisure travelers might place importanceanswered their PATs with a large allowance they addedon service attributes not included in the access modein advance for connection time in case of missing a

choices listed in our questionnaire.

connection or unexpected trouble, they might consider

We want to emphasize that in this model SDE andthe risk of missing a connection low by this much

SDL were statistically significant for both trip purposes.

allowance time and evaluate their needed connect time

In particular, the value of the SDE parameter, which

as shorter. Since we could not clarify these points, weshows disutility of waiting too long at KIX, was higher

need to examine them more carefully in future studies.

than that of other variables for both business and leisureWe estimated the monetary value of time savings withtravel. This result suggested that the SDE variable wasrespect to IVT, SDE and SDL. In the discrete choice

important for business and leisure trips in access mode

model, the value of travel time savings (VOTTS) could

choice. In prior studies, above all, the choice model ofbe obtained from ratios with estimated parameters of

departure time by auto for work-trip, the assumption thattime by estimated parameters of travel cost if the utility

the value of SDE parameter would be smaller than thatfunction was linear. These values could be interpreted asof SDL is now widely accepted. However, our result

travelers’ willingness to pay for saving units of time,

was contrary to this. We can interpret this result as

which is called the subjective value of saving time.

follows. It may be that respondents could not imagine

Table 3
Definitions of explanatory variables
Variables

Unit

Description

Total timemin

Access timemin

From departure time at home to time of taking off at KIX, including access time, travel
time, check-in-time at bus terminals and local airports in Takamatsu or Tokushima,
allowance time and connecting time at KIX.
Travel time from home to local airports or bus terminals in Takamatsu and Tokushima(asked directly in this survey)

Travel timemin

In-vehicle time setting in this survey.

Travel costyen

Ticket price setting in this survey.

SDE

min

PAT-AAT max(0,SDE) if SDE<0,SDE=0

SDL

min

Incomeyen

AAT-PAT max(0,SDL) if SDL<0,SDL=0
Annual household income (in 0000s yen)Calculated as the mid-point of the income interval in this survey

Table 4
Estimation results of the binary logit model for choice of access modes to KIX
Business traveler
Leisure traveler
Parameters.e.
t-ratioParameters.e.
Constant-2.52299 ***0.85023-2.97
1.109570 ***0.39252
Income0.00095 ***0.000146.57
0.000509 ***0.00008
Access time
-0.01047*
0.00544-1.93-0.003134
0.00218
Travel time(IVT)-0.02023 ***0.00495-4.08
0.000004
0.00228
Travel cost
-0.00017 ***0.00004-4.36-0.000228 ***0.00002SDE-0.01168 ***0.00149-7.85-0.011662 ***0.00078
SDL-0.00684 **0.00318-2.15-0.005525 ***0.00144L(β)-423.77-1542.37
L(0)-583.63-1890.21
2
0.27
0.18
2
0.26
0.18
Subjective values of time (¥/h)
IVT
7140.0―SDE
4122.23068.9SDL
2414.11453.9n.Observations
842
2727***Coefficient is significant at the 1% level, **at the 5% level, *at the 10% level.

For business trips, the value of IVT was highest in
2

t-ratio
2.83
6.11
-1.44
0.002
-11.34-14.92-3.83

and SDL variables are set separately in the demand

three time variables, IVT, SDE and SDL . This resultmodels, some studies that do not focus on transfers such

implies that business travelers want to arrive at hub

as departure time choice models by auto on highway

airports as fast as possible to save no productive time toshow a contrary results, which are the value of SDL wasuse such as IVT. Prior studies also showed that the value

higher than that of SDE. Thus there is room forof IVT for long business trips was higher than the values

reconsidering precisely why SDE is higher in ourof other time variables3.

research. However, as Wardman (2001) indicated, there

Comparing values of time for business and leisure, thewas a problem in estimating the value of travel time invalue of SDE and SDL for business was higher than thatearlier studies that did not distinguish disutility offor leisure by 1000 yen. These results are identical withtransfer, check-in time or waiting time individually.

those of prior studies in that business travelers’Rather, considering disutility of transfer was given bywillingness to pay for time is higher than that of leisure

our research design and check-in time and waiting time

travelers. Comparing values of SDE and SDL, SDE waswere separated by setting SDE and SDL variables in ourhigher for both business and leisure. Though there aremodel, our results might be reliable.

few studies of transfers at hub airports in which the SDE

We examined the difference in value of total travel
time savings based on departure time from home. Table

2 In this study, we did not survey individual access costfrom home to local airports or bus terminals, so we did
not estimate the value of access time.
3 For example, Winston (1985), Wardman (1998).

5 shows the estimated results by estimating the cases ofbefore or after noon separately. For both business andleisure trips, all estimated parameters except forconstants were statistically significant and signs were as
expected. What is more, for business trips, we obtained
2stronger in the p.m. case.
The subjective value of total time savings in the a.m.

a robust value 0.26 on ρ . On the other hand, for leisure,

was higher than that in the p.m., as we expected, for

we could not obtain a robust value. As mentioned above,

both business and leisure travel. Our results indicate that

this result might indicate that leisure travelers would

travelers’ willingness to pay for saving time differs

consider other service attributes than those we presented

between the a.m. and p.m. In this research, since total

in this model. It is not easy to know what caused thistime is defined as the accumulated time from leaving

result; we need to examine the data and/or model

home to taking off at a hub airport, including check-in

specifications more precisely.

time, waiting time, access time to service points andHere, comparing the value of the estimated parameterallowance time, this result reflects a more realisticwith total time in the a.m. with that in the p.m., we finddecision-making process of access mode choice thanthe value in the a.m. was higher than that in the p.m. forthat described in some previous studies. Thus, the result

both business and leisure travel. This result shows that

we obtained should be reliable. Since our result was

travelers in the a.m. case would consider the total time,

obtained by the SP experiment we designed, the resultsthat is, beginning with the departure time from home,were not influenced by traffic congestion, which wasmore than would travelers in the p.m. with regard toemphasized in some prior studies. Hence, although weaccess mode choice. Contrary to this, the value of the

did not consider access travel cost to a bus terminal or

estimated parameter with cost in the p.m. was higher

local airports, we believe these values we estimated asthan that in the a.m. for both business and leisure travel.

reliable to some extent.

This result implies that the influence of ticket-price isTable 5
Estimation results of the logit model (depart in the a.m./p.m.)
Business traveler
Parameters.e.
Constant-0.42042*
0.215952
Income0.00085 ***0.000142
Total time (a.m.)-0.01039 ***0.001635
Total time (p.m.)-0.00789 ***0.001262
Travel cost (a.m.)-0.00014 ***0.000049
Travel cost (p.m.)-0.00023 ***0.000049L(β)-429.24L(0)-583.63
2
0.26
2
0.25
Subjective values of time (¥/h)
a.m. departure
4320
p.m. departure2066
n. observations
842

t-ratio
-1.95
5.99
-6.36
-6.25
-2.92
-4.67

Leisure traveler
Parameters.e.
0.081700.104900.00052 ***0.00008-0.00990 ***0.00085-0.00586 ***0.00063-0.00019 ***0.00003-0.00025 ***0.00002-1554.07-1890.21
0.18
0.17***Coefficient is significant at the 1% level, **at the 5% level, *at the 10% level.

3111
1422
2727

t-ratio
0.78
6.44-11.60
-9.33
-7.46
-9.90

As air travel can mean a much shorter travel time than

6. Conclusions
As we have seen, SDE and SDL, reflecting thelimousine travel, using the former can allow passengers

convenience of transfer, have a strong influence on

to delay their departure time from home. Thus, ouraccess modes choice to hub airports for both businessresult shows that travelers would prefer access flights toand leisure travelers. In particular, for leisure travelers,

KIX with a.m. departures to flights with p.m. departures.

although SDE and SDL were statistically significant in

As we have seen, considering travelers’ willingness toaccess modes choice, IVT was not significant in ourpay for saving time differs between the a.m. and theresults. This is inevitable when new access modes are

p.m., it would be inappropriate that the same price be set

planned from local areas to hub airports. Because leisureon the flights service with different times in a day eventravelers are not attracted to such newly flights thatthough they have the same IVT and service attributes.

make them wait for so long time at hub airports, even

Finally, based on our results, we can next present

though flight time, that is IVT, will get much shortersuggestions about access flights to hub airports fromthan that of limousines.

local areas. First, considering convenience of connecting,In general, as market sizes of access modes from local

it is very important that access flights connecting well toareas are small, high-frequency is not expected. It can bepeak-time flights at hub airports will be provided.

inconvenient for travelers to transfer at hub airports, inMoreover, when such flights will depart from local

that SDE might be so long that they must wait for a long

airports in the morning, the ticket prices can betime at hub airports. In this case, sufficient demand for

relatively high, as the dominance of preference for air

new access flight from local airports to hub airports

for express travel is sustained. Second, since passengers

would not be expected when flight price remain highconnecting to off-peak flights at hub airports have to

only considering on relatively shorter IVT to existent

wait for a long time, even if they use the same accessmodes,

flight, ticket prices should be set to reflect SDE cost.

such

as

limousines

without

considering

willingness to pay for saving SDE.

When there are insufficient passengers to accessOn the other hand, our results made clear thatflights from local areas, airlines may be able to improvebusiness travelers would need to save much time for

their load factor and not be unfair to passengers byaccess travel to hub airports, in that values of SDE, SDL

setting prices based on passengers’ willingness to pay.

[2010.12.9 1009]

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