報告論文

Feasibility Analysis of Partial Cooperation between Government
and Port in the Multiple Port System
This paper aims to consider the possibility of cooperative relationship among ports and government
for efﬁcient port management in the southern part of Viet Nam. First, we obtain parameters of theVietnamese shippers’ port choice behavior by using the disaggregated data. Second, we start withthe equilibrium analysis under this situation as the base case. Third, we carry out the feasible studyof the government port vertical cooperation for improving social beneﬁts. Our results show that the
government-port vertical cooperation scheme for port charges is feasible and more efﬁcient than theport expansion in the southern part of Viet Nam.

Keywords

port coordination, vertical cooperation, shipper’ behavior

チャン・ティアンタム

博士（工学） 神戸大学大学院海事科学研究科博士課程後期課程

竹林幹雄

博士（工学） 神戸大学大学院海事科学研究科教授

Thi Anh Tam TRAN

TAKEBAYASHI, Mikio

1──Introduction
The seaborne freight transport occupies about 80
percent in the global trade. Moreover, this share iseven higher in most of developing countries1).
China has become one of the largest consumption
market, and the trend of relocating production
plants from China to Southeast Asian countries
have been stimulating the intra-Asia container
shipping market. Looking at the shipping connection and service level in the intra-Asia, these havebeen improved signiﬁcantly for last two decades.
The number of direct services has increased at
not only hub ports but also feeder ports2), suchas Ho Chi Minh City (HCM) and Cai Mep (CM)port.
Along with the rationalization of small-medium
sized container ports with high growth rate in theexport-based countries, such as Viet Nam, these
ports have created new trends for container port
developments. However, one common problem
for Southeast Asian countries including Viet Nam
is the “big gap” in transport infrastructure development among countries. The growth rate in container freight and passenger vehicles has exceeded
the increase rate of capacity of surface infrastructure in megacities. Although Viet Nam has followed the socialistʼs orientation for controlling the
学術研究論文market since 1986, in the era of internationalization, many stakeholders in freight transport market, say, shippers, carriers, and freight-forwarders
may not have a place for policy making in Viet
Nam. Hence, the government-planned mechanism
reveals its weaknesses when trying to re-bundle
freight commodity ﬂows in the multiple stakeholder port system.
As for researches about container port competition, various papers have studied the competitionand cooperation among (major) ports. They challenge this target by the network design approaches3)-5); game theory6); contestability7), 8), and themultitude of participants concern9). When dealing
with cooperative schemes in transportation, there
are two main research streams deﬁned as “vertical cooperation” and “horizontal cooperation”.
Horizontal cooperation has been studied amongports5), 8), 9), among shippers10)-12), and among carriers13), 14). These researchers have the following
assumption: ports aim to seek revenue or market
share growth; carriers mainly aim to reduce costsin the competitive market. As for shippers, they
are assumed to collaborate in order to negotiate
better rates with carriers. Asgari et al.5), study thevertical cooperation between shipping companies
and the hub port, and they ﬁnd that forming strategic alliances with leading shipping companies
早期公開版 Vol.20 2017 運輸政策研究001

can help to guarantee the market share in medium and long range.
The researches mentioned above researches
mainly focus on the competitive and cooperative
relationships among a few mega hub ports: Hong
Kong vs. South China Port, Busan vs. Shanghai,
Singapore vs. Klang port, etc. These ports whosewaterfront and infrastructure for port connectivity
has been sophisticatedly built can provide highproductivity and good service for port users. But,on the other hand, few ports can enjoy the success in the competitive market. Studying the relationships among stakeholders relevant to thesesuccessful ports will contribute to the emerging
and newly developed ports: in particular, the policy and implications will be beneﬁcial for infrastructure and port development.
One possible strategy is the “co-opetition.” Thisidea means the partial cooperation in the competitive market8). This strategy has been widely
applied in the supply chain and logistics management. A prominent example of this relationship is
the General Mills Yogurt and Land Oʼ lakes butterdelivered by the same truck, en route to the same
supermarket15). Chen and Chang16) investigate the“co-opetitive” strategy of a closed loop supply
chain which incorporates with remanufacturing.
Li and Zhang17) propose a new model that allows
shipping forwarders to share their shipping
capacity before setting the selling prices and satisfying demand from shippers. Caballini et al.18),
study the collaboration among multiple truck carriers in the seaport containerized environment for
maximizing their total profit. Hafezalkotob19)
applies the concept of “co-opetition” to consider
how to improve energy-saving efforts to improve
the performance of rival green supply chains given the ﬁnancial interventions of the government.
Regarding port “co-opetition”, Song8) proposes
this interesting idea of selective competition or
partial cooperation. He argues that the desiredcompetition scheme for major ports in the future
is to “ﬁnd the companies, get together and compete with rivals.” Their suggestion also meansthat the port consortium can improve their port
productivity by economy of scale. The important002

運輸政策研究 早期公開版 Vol.20 2017

point is to ﬁnd “what kind of partial cooperation
works well.” But, both United Nations Conference
on Trade and Development 20) (UNCTAD) andSong8) conﬁrmed that a balance between cooperation and competition should be found to securecommercial and social interests, and this balancevaries with the case, the country, and the region.
UNCTAD suggests that a cost/benefit analysis
should be carried out to know if it is better tocompete or to cooperate.
This paper aims to form a competition model bywhich we can measure the welfare included port
users’ benefits. We also carry out the scenario
studies on the partial coordination of port/
government-shipper and evaluate the feasibility ofthe partial cooperation.
This paper has four bodies. Section 1 is introduction. Section 2 describes model structure and formulation. Section 3 demonstrates port choicemodel with parameter estimation for short-haultransport for shippers from the southern part ofViet Nam, ﬁnding the best response strategies foreach port when there is no cooperation, andshows the results of scenario studies of CM port/
government coordination. Then we discuss thefeasibilit y of subsidy plans in each case.
Concluding remarks are presented in the final
part.

2──The model
2.1 Description of problem

In this paper, we focus on the situation in thesouthern part of Viet Nam. This area has two
ports: one is HCM and the other is CM.
Port 1 (HCM), which locates nearby the Central
Business District-/CBD, holds about 70 percent of
total regional container handling throughput. Port
2 (CM) has been newly developed port since 2009and it has a deep draft which can invite bigger
vessels compared with HCM. Thus, CM is morecompetitive against HCM for long-haul transportcargo. But, in terms of short-haul transport services, most shippers choose HCM port for export.
Choosing HCM export has a long history andthen this “custom” cannot be changed easily
学術研究論文4,000

7,000

5,000

Thousands TEUs

Thousands TEUs

6,000

4,000
3,000
2,000

3,000

2,000

1,000
0

2009

2010

2011

Total CMP
(a)

2012

2013

2014

2015

1,000

2011 2012 2013 2014 2015 2016 2017 2018 2019

Planned Capacity

PlannedActual Throughput(b)

Forecast

Source: authors composed data from Tran and Takebayashi [2014]22)■ Figure—1

C bserved throughput and planned capacity of CM 2009-2015 (a); Planned capacity 2011-2019, observedO
throughput 2011-2015, and forecast 2016-2019 for Cat Lai Terminal of HCM (b)Reduce port congestion at HCMC
GovernmentCharg）
o n Conn e Orit
ect derpOivit , Imr（y（edOp proveOrtion Hi
e
g
nte
r
）
ha
rl

Maximization of Profit
HCMC
rgo

Maximization of Profit
CAIMEP
Ch

arg

e

Ca

rg

o
ChargeMaximization of Profit
Carriers
Informationof Frequency

Route Choice

Route Choice

Ca

and

Shippers
Maximization of Utility /Minimization of Disutility■ Figure— 2

Relationships among stakeholders for freighttransportation market in South Vietnam

because (i) most of the trading contracts are signed
in f.o.b (free-on-board) terms by which exporters
are responsible for paying inland-drayage cost to
port of loading, (ii) the close proximity of HCM
port is attractive for shippers to minimize thetransport cost. Viet Nam becomes more integrated
into regional economic activity and then the economic initiatives such as ASEAN Economic
Community, Free Trade Agreement with ASEANChina, and potential Trans Pacific Partnership/
TPP will stimulate seaborne freight cargo ﬂows in
the intra-Asia. HCM port works as a gateway port
for South Viet Nam, and then HCM will face serious port congestion within a decade.
The cause for congestion could be traced back to
the Five-Year Master Plan of Port Development
学術研究論文since 201121): the central government ordered thatthe new port CM takes over the role of gateway
port for the southern part of Viet Nam because
HCM port cannot expand its capacity. One might
think that HCM port can act as the secondary
port gradually. However, ﬁve years later, the governmentʼs survey suggests that the market does
not perform as what had been planned. Panel (a)and (b) of Figure̶1 show the big gap between
planned data and market data of two ports.
To find a solution for the problem of overinvestment in CM and heavy congestion in HCM,
it is necessary that we set up the central governmentʼs objective in a larger context where we
consider the beneﬁt of shippers, ports and carriers. Figure̶2 shows a model structure that
includes all stakeholders in the market. Looking at
Figure̶2, we consider four types of player
Ministry of Transport is placed in the top layer onbehalf of the central government; terminal operators is in the second layer; the carrier is in thethird; shippers are at the bottom. The behavior of
terminal operators affects the carriersʼ and shippersʼ behavior. The relation between carriers andshippers is dependent on each other. Thus, thisproblem can be regarded as the family of supplydemand interaction problem.
The government has some options of port management policy. The government has a strong
presence in the market that has the power toinﬂuence shippersʼ decision by requesting ports
their handling charges. The government is the
早期公開版 Vol.20 2017 運輸政策研究003

major shareholder of both ports, and the government is also in charge of constructing waterfront
infrastructure, navigational channels, and surface
transport connectivity with ports. Then, the government has an opportunity to control cost factors such as terminal handling charges (THC),
ship tonnage tax, and inland drayage cost, andtime factors such as inland drayage time. We willproceed to the scenario studies for evaluating thepolicy options.
In addition, we assume that the government aims
to reduce the port congestion at HCM port.
Improving the welfare consisting of shippersʼ utility and portsʼ proﬁt will be discussed from thedifferent point of view later.
Although the full model is shown in Figure̶2, it
is too complicated to handle. Since we focus on
shippersʼ route choice behavior reflecting eachportʼs strategy, we simplify the model structure as
the carriers take the passive roles. This meansthat carriers change service frequency for matching the cargo flow but they do not change
charges. Eventually, we have three players: theshippers, the ports, and the government.

(2)
subject to
for

(3)

where xl n: cargo ﬂow on link l n;δhln : binary variable take one when link l n at port h, otherwise
take zero; x krs: path ﬂow on kth route of rs OD
pair (origin r destination s); δlrsk
n : binary variablentake one when link l on k th route of rs OD pair,otherwise it takes zero. l n: a set of links operated
by carrier n.
2.2.3 Carriers

The intra-Asia transport market is assumed towork as the perfect competitive market. Then we
skip the identiﬁcation of carriers and drop n fromthe formula. Under the perfect competition, carriers can gain maximum profit as zero, and theocean tariff ql should be given as the marginalcost. Operating cost per vessel is deﬁned as Cl,
and the capacity is vl. When the carrier sets theservice frequency with 100 percent load factor,
the tariff should be constant and shown as:(4)

2.2 The general formulation of the model
2.2.1 The government

The government aims to minimize the congestion
on the inner-city port. The port congestion formulation is given as(1)
where TP is the throughput at port h; PC is theplanned capacity. The objective functions of thegovernment is relevant to the scenarios and thenwe show them in the scenario study part．
2.2.2 Terminal operator/ Port

Terminal operator iʼs purpose is to maximize its
proﬁt by controlling port charges loaded by carriers. Let the port charge of terminal operator i at
port h be ρhi ; ρ-i is port charge of the rival port .
In the following formula, l n means the link operated by carrier n. Gathering containers bringmore proﬁt to the terminal operator, and then the
proﬁt maximization is formulated as004

運輸政策研究 早期公開版 Vol.20 2017

2.2.4 Shippers

Shippersʼ aim is to maximize the utility as muchas possible. In order to achieve this, they decideto choose the routes and ports carefully. Theirobjective function is given
as

(5)

where
(6)
The signs in the brackets are the expected signs
by the parameter estimation.
In the eqn. (5), we deﬁne: Size: vessel capacity ofcarrier c in TEU on link l; Σl/Ofreq: inverted sailing frequency in one month; Ltime: inland drayage time (in days); Tcost: generalized total cost;
OF : ocean freight; THC : container handlingcharge at port of loading h; Lcost: inland drayage
学術研究論文cost for shipment k th.

3──Parameter estimation andscenario studies
3.1 Parameter estimation

We need to estimate the parameters for applying
our shipper model. In this subsection, we brieﬂyshow the process of parameter estimation.
3.1.1 Data

We aim to develop the port choice model forshippers based in the southern part of Viet Nam,particularly the intra-Asia transport ﬂows; our targets are Hong Kong, Kobe, Manila, Nagoya,
Osaka, Shenzhen, Tokyo, and Yokohama ports.
The reason we decided to choose short-haultransport market is that HCM port are now dominating in the intra-Asia transport, while CM takes
over the transpaciﬁc transport. Our research goal
is to help proposing plans to reduce the congestion at HCM. Hence, in this sub-section, we
decided to find out attributes influencing port
choice of shippers in the intra-Asia freight market.
For this aim, we need to gather the comprehensive OD data, but unfortunately, Viet Nam does
not provide the comprehensive OD data. Thus, webuilt the dataset by contacting multiple port stakeholders in Viet Nam. First we collected individual
container information (shipping route from origin
port to final destination port via transshipment
port, carrier, type of service, port dwell time, andvessel size) from major container terminal ports
in the southern part of Viet Nam, namely Cat Lai
Ter minal in Ho Chi Minh Cit y, Tan Cang
International Terminal and Cai Mep International
Terminal in Ba Ria Vung Tau Province in May
2015. Second, we interviewed several Ho Chi
Minh City-based container carriers, trucking companies, and Tan Cang Waterway Transport JSC
about the ocean freight and local transport costs.
Third, we gathered the information about theocean service frequency from MDS Transmodal.
By combining the information from the several
sources, we have a unique dataset which is com学術研究論文

posed of totally disaggregated information.
We obtain four alternatives of port-inland drayage
model. The inland drayage factors include “totaltransport cost” and “local transport time”. Our
hypothesis is that ocean freight for the intra-Asia
trade routes do not vary with the port of loading.
The dataset includes 5,760 samples composed ofeight OD pairs: each shipper has four shipping
route alternatives, namely CM-Barge, CM-Truck,
HCM-Barge, HCM- Truck. For CM, 52.5％ of shipments were delivered by river barge, and 4.67％
came by truck. HCM port, by contrast, received
39.4％ of shipments from truck and 3.33％ frombarge.
3.1.2 Results

For estimating parameters, we apply the maximum likelihood method using N-LOGIT ver 4.0.
The summary of result is shown in Table̶1.
Three out of four coefficients are statisticallysignificant (see P-statistic in Table̶1). All thesigns of obtained parameters are as expected in
eqn. (5). McFaddenʼs R2 is 0.16, which is approximately 0.45 which is equivalent to R2 of the linear
regression model23).
In the detail of estimation, we can say that shippers prefer port that can attract larger container
ships. Increasing the service frequency would bedesirable for shippers. This factor can be regarded as the most critical factor because the absolutevalue of parameter is 3.58. The second rank ofsignificance is the generalized total cost, while
the inland-drayage time is not so important toshippers.
Fig ure ̶ 3 depic t s t he compar ison of t he
■Table—1

Parameter estimation

Variable

CoefficientStandard
Error

Vessel size (TEU)

0.000860.0000193

44.41

e －4

Inverted Frequency(vessel/month)－3.5880.354－10.13e－4

Total cost (USD)－0.01260.00026－48.06e －4Inland time (days)－0.00201

0.0058

－0.34

0.73

Loglikelihood(base)
Loglikelihood(coefficient)
Pseudo R2

Z-statistic P-Statistic

－4339
－5032

0.16

早期公開版 Vol.20 2017 運輸政策研究005

observed and computed OD cargo ﬂows. Seeing
Figure̶3, the model overestimates or underestimates in some OD ﬂows. However in spite of thelimited information, the model can provide relatively good reproduction. Thus, we can use thismodel for further scenario studies.
3.2 Scenario studies

In this subsection, we carry out some policy scenario studies to conﬁrm the workability of policy
options we set up. We start with non-cooperative
situation as Base Case. As for the solution, we
adopt the Nash equilibrium as the equilibrium
solution in the port competition layer. After analyzing Base Case, we turn to the scenarios of partial cooperation between the government andone port (CM), while two ports are competing
against each other.
3.2.1 Non-cooperative situation

Under the non-cooperative situation, the government has no chance to improve the port congestion at HCM without forcing.
In the following study, we assume “one port one
operator” because we mainly want to focus on
the competitive relation between ports and avoid
handling too much complex structure of the market. Under this assumption we consider each port
aims to maximize their proﬁt by controlling thehandling charges. Based on the formulation
shown in eqn. (2) and (3), the problem of port hcan be simpliﬁed as(7)

Subject to p hl ≤ p h ≥ p 2h.
In the formulation, we define: p h: handlingcharge at port h, p -h: handling charge at rival
port; x: cargo ﬂow from r to s on k th route; δhrsk:
binary variable which takes one when route k on
rs OD pair use h; otherwise takes zero.
We assume the logit type flow allocation, andthen the cargo ﬂow xkrs is given as(8)
In this application, we propose three different
levels of handling charge for one twenty-footequivalent unit (TEU), which are 20, 40, and 82
USD. The upper limit, 82, is the ofﬁcial port handling charge24). There are exactly nine combinations shown in Table̶2.
The matrix (i.e., the nine squares in Table̶3)
contain the payoffs, i.e. proﬁt, to HCM port (onthe left-hand side) and to CM port (on the righthand side), corresponding to above combinations.
Table̶3 shows the matrix of proﬁt of each port
and we can find a Nash equilibrium. Table̶3
says that both ports choose the highest possible
price, 82 USD per TEU. The gained profits of
HCM and CM port are 258,710 USD and 377,774
USD, respectively. The market shares of CM and
HCM at Base Case are 58 and 40 percent, respectively. The rest of shipments are diverted to otherport. The total disutility of shippers is obtainedas -11925.
3.2.2 Partial cooperation between government and the
port

When we consider the cooperative situation
1,000■Table— 2

Matrix of port charge combination
CM 20$CM 40$CM 82$

HCM 20$(HCM20, CM20)(HCM20, CM40)(HCM20, CM82)

HCM 40$(HCM40, CM20)(HCM40, CM40)(HCM40, CM82)

HCM 82$(HCM82, CM20)(HCM82, CM40)(HCM82, CM82)■Table— 3

P rofits of HCM and CM port under the noncooperative situation(in USD/month)

800
600
400
200
0

CM 20$

0■ Figure— 3

006

200

400

600

800

1,000

C o m p a r i s o n o f o b s e r v e d a n d c o m p u t e ddistribution of shipments (unit: boxes)

運輸政策研究 早期公開版 Vol.20 2017

CM 40$CM 82$

HCM 20$ (63700, 93300)(72680, 168400)(89420, 275356)

HCM 40$ (149160, 82260)(127480, 185640) (148920, 330214)

HCM 82$ (160884, 116960) (187370, 220400) (258710, 377774)
Unit: USD/ month

学術研究論文■Table— 4

Four scenarios of CM- government coordination

Case

Description

1

CM reduces THC to 40 USD per TEU

2

CM reduces THC to 40 USD per TEU, Trucking cost to CM decreases by 25％

3

CM reduces THC to 20 USD per TEU

4

CM reduces THC to 20 USD per TEU, Trucking cost to CM decreases by 50％■Table— 5

Profits of HCM and CM port under cooperation (in USD)

HCM

Case 1 (1)Case 2 (2)Case 3 (3)Case 4 (4)20$(72680, 168400)(68580, 176720)(63700, 93300)(63820, 93180)

40$(127480, 185640)(128200, 185240)(149160, 82260)(84480, 113780)

82$(187370, 220400)(169002, 229840)(160884, 116960)(116850, 128460)

among players, we need to assume the following
conditions.
1) Ports can have cooperation if and only if all
players have the cooperation. Otherwise, they
compete with each other.
2) Under cooperation, each player accepts thecontract of “keeping the improving ratio bigger
than ε(％).”
Condition 1) is for avoiding the cartel amongports. Under this competitive situation, the Nashequilibrium is equivalent to the cartel solution.
Then, usually this kind of situation is not desirable for other players i.e. government and shippers. Thus, we have the strict assumption that
this kind of cartel is acceptable if and only if thegovernment and shippersʼ beneﬁt is improved.
Condition 2) seems to be a strict condition for
obtaining the rational solution as the cooperation.
We consider the negotiable solutions among players. Then, ε should be given by scenarios. The
government always considers improving total
shippersʼ utility (ε1) and HCM port congestion (ε2)
as much as possible. The improvement of shipperʼs utility (ε1) in this case is the percentage of
decrease in total (dis)utility of the market from
eqn. (5) compared with Base Case. Next, theimprovement of port congestion (ε2) in HCM port
is deﬁned(9)where X: total cargo volume (TEU) of HCM port
in scenario n; 0 : Base Case.
We set up some scenarios in Table̶4. First, weconsider the simple cooperation between government and CM: the government negotiates with
学術研究論文

60
39.4

40
19.6

20
0

24.7

27
CM

Case 0 Case 1 Case 2 Case 3 Case 4

HCM

−20
−40
−60
■ Figure— 4

−27.5

−37.8
−34.6
−55

Impact of THC and Trucking cost at CM on
cargo volume change (％)

CM port about lowering handling charges (Case 1
and 3). The following scenarios are of additional“incentives” for succeeding the CM port coordination: we set up that the trucking cost to CM isdecreased by c1 and c2 percent (case 2 and 4).
For each change in charging policy of CM port,
we assume that HCM port faces the competitive
situation, thus, it will choose the pricing strategy
that maximizes proﬁt. The corresponding proﬁts
are shown in Table̶5 (see column (1), (2), (3),(4)). In each cell, HCMʼs proﬁt is on the left handside, and CMʼs is on the right hand side. The
Nash equilibrium between two ports under cooperation can be obtained when HCM chooses thehighest possible price (82 USD) to gain the highest possible proﬁt.
Figure̶4 describes the impact of port charges
and trucking charge policy on cargo volume of CM
and HCM. From the ﬁgure, we understand that the
reduction of port charge and/or trucking charge at
CM will directly decrease the share of HCM port.
Table̶6 compares the ε1, ε2 improvement of shipperʼs utility and port congestion under different
scenarios which are proposed by government.
早期公開版 Vol.20 2017 運輸政策研究

007

From Table̶5, our ﬁndings are:1) Even though CM por tʼ s cargo share isincreased in each case (see Figure̶4), it does
not compensate for their loss of proﬁt (see column (3) of Table̶6). Then, subsidy programs
are needed to have CM portʼs coordination.
From the government viewpoint, the solutions
seem to be feasible if the subsidy is less thanthe value of improvement on port congestionand shippersʼ utility.
2) If the government aims to reduce congestion
by less than 30 percent, scenario 1 is an
option. CM portʼs coordination is charging the
THC by less than 50 percent of Base case.
Their loss of revenue is 157,374 USD a month.
3) If the government aims to reduce congestion
by less than 40 percent, scenario 2 and 3 areacceptable. In Case 2, trucking companies
share the loss of revenue with CM if they agree
to charge less than 25 percent for delivering
shipments to CM port. In case 3, CM port
reduces its THC to 20 USD per TEU, and thenshippers will choose CM more. As a result, thetotal disutility decreases by 26.2 percent.
4) If the government intends to reduce congestion
more, say, more than 50 percent, CM handlingcharge needs to be declined by 75 percent, andthe trucking rebate is 50 percent (see case 4).
Shippers and government have the biggest
beneﬁt in this case, but the trade-off for this is
the total loss of 480,316 USD per month.
3.2.3 Feasibility study of subsidy plans

As mentioned above, evaluating the feasibility ofthese coordination is an important step to confirm whether cooperation will bring benefit toeach port, shippers and the society (in terms of
reducing port congestion). A subsidy plan seems■Table— 6Case

ε2 b of port

congestion

Loss of CM
port cLoss oftrucking
charged
(4)

(1)

(2)

(3)

1

－16.6

－27.6

157,374

0

2

－16.5

－34.7

147,934

102,123

3

－26.2

－37.8

260,814

0

4

－34

－55

249,314231,002a, b: in %, c, d: USD per month008

運輸政策研究 早期公開版 Vol.20 2017(10)
V rs: total disutility of shippers in scenario
where Σn kn; β3 : estimated parameter for generalized total
cost in (5).
The total amount of the budget of Ho Chi Minh
City Authority to improve HCM port connectivity
infrastructure for 2016-2020 period25), 26) is 242
million USD, and then this cost can be regarded
as the total congestion cost by the government.
Assume that every percent of decrease of ε2 (seecolumn (2) of Table̶6) equals to the savings
ratio of congestion cost. The monetary value ofcongestion improvement equals(11)
where 4％ is the share of in-sampled cargo in our
computation compared with the total intra-Asia
trade volume.
Table̶7 lists the corresponding results ofimprovement for shippers and port congestion inmonetary value in each case.
The result in Table̶7 shows that there are two
feasible port cooperative schemes, case 1 and 3.
Both cases can generate more total improvement
for the society than the subsidy (see column (3)and (4)), thus both social and commercial interests are secured. This implies that the coordination strategy with CM port where they discounthandling charges for shippers might be feasible inpractice.

■Table—7

Pay-offs of players under scenarios

ε1 a ofdisutility

to be feasible if it is smaller than the total
improvement of port congestion and shipperʼs
disutility. To measure the disutility (ε1) and port
congestion (ε2) in monetary value ($), we formulate ost/benefit analysis for CM port and drayage
Ccharge policy (in USD)

Disutility
Congestion
Total
Total subsidy
Case improvement improvement improvement
(1)e
(2)f
(3)=(1)+(2)(4)g1

157,143

44,528201,671

157,3742

156,11155,983

212,094

250,0573

248,333

60,984309,317260,8144

321,429

88,733

410,162

480,316

e: U $ - U $ according to eqn. (10); f: according to eqn. (11); g: total loss of revenuen0of CM and trucking company in Table—5

学術研究論文3.2.4 Other forms of cooperation

Besides port-government vertical relationship, we
tried other scenarios about the barge carriergovernment cooperation (case 5) and horizontal
cooperation between two ports (case 6, 7) under
the government ﬁnancial intervention. In case 5,
river barge cost to CM is reduced by 25 percent.
In case 6 and 7, HCM agrees to ﬁx the THC at
150 USD, while CMʼs THC is 40 and 20, respectively. In the same way, the cost/beneﬁt analysis
on these cases is conducted. Table̶8 represents
the result. As total improvement is less than total
subsidy, we ﬁnd that these forms of collaboration
are not feasible.

4──Concluding remarks
This paper deals with the port management issue
in the southern part of Viet Nam and discusses
the feasibility of government-port vertical cooperation for solving the management issue. We apply
the game theoretical approach for tackling thisissue considering Vietnamese shippersʼ route
choice behavior. By setting some scenario studies, we carry out the feasibility study on port anddrayage charge policy coordination between thegovernment and CM port in order to reduce congestion at the inner-city port, and to improveshippersʼ beneﬁts.
Our results suggest that the port charge coordination plan with subsidy can be feasible and more
efﬁcient than the port expansion of HCM. Thissuggests that the port expansion is not the only
way to reduce the congestion and to improveshippersʼ benefit in the southern part of Viet
Nam. The vertical (partial) cooperation between■Table— 8

Cost/benefit analysis
Case 5

Case 6

Case 752,56262,81079,460Loss of CM(54,530)

120,534

246,294

Loss of barge carrier

179,248

Loss of HCM

Total subsidy

179,248

183,344

325,754

Disutility improvement

130,237

76,093

199,832

Congestion improvement

32,77894,550100,226

Total improvement

163,015

170,643

300,058

Unit: USD

学術研究論文the government and not-congested port, i.e. CM,
can be more efﬁcient and workable in terms of
cost/beneﬁts. Viet Nam has suffered from the big
gap between the planned capacity and the actual
demand, and then the approach from the viewpoint of management of multiple port system canbe a useful option. But, this workability, ofcourse, should be confirmed from the wider
viewpoint of regional economies because we justdeal with the transport market so far.
Before closing this paper, we need to note ouranalysis is done under some strict assumptions.
We consider the feasibility of the partial cooperation considering the improvement of shippersʼ
benefits. However, we cannot address the
improvement of a “social welfare” because we
assume that carriers act as passive players, but inthe real world, the carriers play active, i.e. changing their fares as well as constructing routes. To
avoid too much complexity, we neglect of theeffect of the carriersʼ active behavior. Our next
research should handle this effect to evaluate thefeasibility of partial cooperation from the viewpoint of the improvement of social welfare.

Acknowledgements

This paper is written based on the practical track
presentation at TLOG 2016, Hsinchu, Taiwan. We
appreciate Prof. Itoh who gave us some meaningful suggestions. We also appreciate Waterfront
Vit al i zat ion and Envi ron ment Research
Foundation Japan (WAVE) who supports thisresearch.
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（原稿受付2016年12月7日）

垂直的協調を考慮した複数港湾システムにおける部分協調の可能性に関する研究
本稿ではベトナム南部の港湾を対象として複数港湾の効率的運営方法について考究した．特に，政府と港湾との垂直的協調の可能性について検討した．まず，非集計データによるベトナム荷主の港湾選択行動についてパラメータ推定を行った．次に同定した荷主モデルを用いて2港湾の競争状態における解を求めた．続いて港湾と政府のとの垂直的協調について検討し，その結果，垂直的協調を行う場合，政府補給金を伴う港湾費用引き下げ政策は港湾の拡張政策よりも有効である可能性があることを示した．
キーワード ; 複数港湾運営，部分協調，荷主行動010

運輸政策研究 早期公開版 Vol.20 2017

学術研究論文