Journal of the National Institute of Public Health2013 Vol.62 No.1 p.52−61

Topics：Strategic management of evidence-based health and medical care policy: How to use new Digital Big Data in health care system＜Review＞
Accessibility to medical care in case of major disasters
Ryo SANUKI１），Eiji SATOH２），Toshiro KUMAKAWA３），Tohru YOSHIKAWA１）
１）

Department of Architecture and Building Engineering, Tokyo Metropolitan University
Graduate school of Engineering, Utsunomiya University
３）
Department of Health ＆ Welfare Service Research, National Institute of Public Health２）

Abstract
When the 2011 Tohoku Earthquake occurred in Japan, the term unforeseen was often used todescribe the scale of the disaster. As symbolized by this, it has become evident that the accumulatedplans based on the concepts of risk management, including disaster prevention, disaster reduction, anddisaster preparation, were not sufficient to prepare for major disasters. Therefore, reconsidering theseissues from the viewpoint of crisis management will surely become very significant in the future.
As is well known, the accessibility to various local facilities decreases in the event of a disaster, andthe degree increases as the scale of the disaster becomes larger. Furthermore, the limited supply of aservice can easily cause a situation in which not all consumers can receive the service. Especially for
local facilities, where high demand rises in cases of emergency, it is important to consider the scale ofits impact and have ways to assess the degree of change and locations. Medical service is one of theservices that will incur increased demand in the event of an emergency such as a disaster. Therefore,
realistically speaking, the “availability” of facilities, which means the change in accessibility to medical
facilities as well as the possibility of receiving medical service in the event of a disaster, will be verysignificant issues.
In this paper, changes in accessibility are examined with a focus on access to medical facilities in theevent of a disaster. Also, based on the actual condition that most emergency transportation for injured
and ill people in the event of a disaster is by general-purpose car, ideal transportation behavior is
discussed. Specifically, with the advanced emergency medical care facilities in the disaster area of
Miyagi Prefecture as a target, the change in accessibility before and after the earthquake is analyzed,
while the capacity of these facilities is assumed to analyze the accessibility to available facilities when asimultaneous outbreak of injured and ill people occurs. For the analysis, accessibility is substituted byroad distance; the Geographic Information System (GIS) is used to measure road distance.
The result of analysis showed that the average travel distance to advanced emergency medical
facilities after the earthquake increased by 12% in all of Miyagi Prefecture after the earthquake. Also, it
indicated that following a guided plan could lead to reducing the travel distance by 30% in comparison to
search type behavior.
keywords: disaster, emergency transportation, accessibility, network distance, GIS, Miyagi(accepted for publication, 17th January 2013)

Corresponding author: Ryo Sanuki
1-1 Minami-Osawa, Hachioji-shi, Tokyo, 192-0397, Japan.
E-mail: sanuki-ryo@tmu.ac.jp

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Accessibility to medical care in case of major disasters

I.

Introduction

Earthquakes are well known in Japan. As many seismic
disasters happened in the past, including the Great HanshinAwaji Earthquake of 1995, the Mid-Niigata Prefecture
Earthquake of 2004, and the Tohoku Earthquake of 2011,
there is a constant demand for plans with risk management
concepts such as disaster protection, disaster reduction,and disaster preparation.
However, due to unpredictability of disasters, dealing
with disasters only with the concept of risk management is
not possible. Therefore, the management concept in theevent of a disaster, which is the idea of crisis management,
becomes important.
As we know, accessibility to various local facilities
decreases in the event of a disaster. As the scale of adisaster becomes larger, its impact on accessibility
increases. Especially regarding local facilities where highdemand rises in the event of an emergency, it is importantto have ways to predict and assess the degree and locationof changes while taking the degree of impact into account.
Also, limited supply can easily cause a situation in which
not all consumers can receive the service. Therefore, it isalso important to prepare ways to predict and assess such asituation.
Medical service is one of the services that will haveincreased demand in the event of an emergency such as adisaster. Therefore, realistically speaking, along with thepossibility of receiving medical service, the change inaccessibility to medical facilities in the event of a disaster isalso another very significant issue. Based on these factors,
discussing crisis management from a viewpoint ofaccessibility is considered to contribute to creating a
response plan for expected major disasters in the future.
There are a wide range of existing research papers that
discuss medical service from the viewpoint of accessibility
and earthquakes, such as a study evaluating accessibility to
medical service in ordinary times, a study investigating
behavior characteristics of injured and ill people inambulance placement during a disaster, and also a study on
simulation model building based on those. For example,
Satoh [1] conducted an evaluation analysis of therelationship between medical facilities and users by spatial
accessibility, which is road distance, based on therecognition that guaranteeing access to medical facilities
within a constant level of spatial and time distance isimportant in building a sustainable health care system.
Based on understanding the significance of utilizing
expressways in improving accessibility from the scene of
injury or illness to medical facilities, Orita et al [2]. analyzed
ideal expressway construction and improvement from theviewpoint of emergency transportation. Among the study
cases investigating the behavior characteristics of injured

and ill people, Sugimoto [3] and Ukai et al [4]. pointed out
the characteristics of injured and ill people as having atendency to rush to nearby medical facilities instead ofgoing to ones at somewhat greater distance. Also, while
taking such behavior characteristics of injured and ill
people into account, Koike et al [5]. focused on thetransportation system in the event of a disaster andproposed a method to predict the number of injured and ill
people visiting each medical facility. Utilizing information
and a chain-of-command structure that set regulations fortreating injured and ill people as the key factors to smoothly
operate an emergency medical transportation system, Baba
et al [6]. developed a simulation model of an emergency
medical transportation system that corresponds to awidespread disaster.
However, even though these studies were reviewed,
there are still only a few that assume and consider abehavior scenario based on the transportation behavior
characteristics of injured and ill people. As pointed out by
Nakano et al [7]. and Kosaka [8], specifically, considering
the high ratio of using general-purpose cars for transporting
injured and ill people in the event of a disaster, it is relevant
to conduct accessibility evaluation based on a transportation
behavior scenario that takes such a fact into account.
Therefore, while learning about the circumstances of amajor disaster from past cases such as the Tohoku
Earthquake, this study emphasizes the significance ofproposing a new management method for transportation
behavior. Also, the results of analysis of accessibilitychanges before and after the earthquake are shown, and amethod to improve efficiency in transporting injured and ill
people is proposed. Understanding accessibility changes inthe damaged area is considered to be a helpful record forsupport and recovery of other areas that face disasters in
the future, thus contributing to the discussion of crisis
management. Moreover, through focusing on a shortage ofsupply in goods and service that becomes a big problem inthe event of a disaster, proposing an analysis method for theavailability of medical service and accessibility to available
medical facilities will also contribute to further developing
the crisis management discussion.

II. Accessibility change before and after the
Tohoku Earthquake
Still vivid in most people’s memories, serious damage
was caused by tsunami in the Tohoku Earthquake. On
March 11, 2011, a major earthquake of magnitude 9.0 hit
eastern Japan and brought widespread damage to thecoastal Tohoku and Kanto region. With its tremendous
power, the tsunami swept away every kind of building,including houses. Regarding medical facilities, which
experience a sharp increase in demand in the event of anatural disaster, many in the area were shut down due to

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the damage caused by the earthquake and tsunami. As aresult, it created major problems for injured and ill people
to receive medical care.
Miyagi Prefecture, the target area of this study, is one of
the major disaster areas affected by the Tohoku
Earthquake. Examining to the coastal region hit by thetsunami, the geographical feature of the northern part is ria
coastline that stretches south from Iwate Prefecture; part of
Kesennuma City, Minamisanriku Town, and Ishinomaki
City are in the indented landform. Urban areas in such alandform tend to experience decreased accessibility after adisaster.
The southern part of the coastal region is made up of the
Sendai Plain. Since there is nothing separating the Pacific
Ocean and the urban area, the tsunami hit a wide range ofcoastal areas of Sendai City, Natori City, and Iwanuma City.
As in the northern coastal region, many medical facilities inthese areas were shut down. However, considering thepossibility of replacing them with the medical facilities in
the areas that escaped damage from the tsunami after theearthquake, we can imagine that the decrease inaccessibility was not as serious as in the northern coastal
region.
Factors that have a major impact on the change ofaccessibility before and after the earthquake are: (1)damaged traffic network, (2) loss of facilities, and (3)movement and change of population. Regarding (1), many
areas had roads restored in the early stage, thus the impact
was minimized. On the other hand, for (2) and (3), thedramatic changes in these factors are considered to have agreat impact on the change in accessibility.
Also, in this study, the definition of “before theearthquake” is March 10, 2011, and “after the earthquake”
is March 11, 2012.
1. Method of measuring accessibility
In this section, accessibility to advanced emergency
medical facilities before and after the earthquake in Miyagi
Prefecture is observed. To conduct the analysis,
accessibility is represented by road distance. As pointed out
by Satoh [1], it is generally ideal to evaluate accessibility to
medical facilities by time distance. This is based on the
viewpoint that there is spatial distance between the origin of
demand and supply, which is between the location of injury
or illness and the medical facility, and thus streets are usedas the main mode of transportation for emergency medicalcare. Therefore, from this viewpoint, a road distance is used
for the analysis in this paper.
Many of the advanced emergency medical facilities in
Miyagi Prefecture are designated emergency hospitals.
Because some of them participate on a rotating schedule, in
the analysis it is necessary to take into account that thehospital in service changes every day. However, it should
not be a problem to assume that all facilities will be

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operating in the event of a disaster. This study especiallyplaces emphasis on accessibility evaluation in the event of amajor disaster, and thus it is assumed that all the facilities
are in service. Although there were 75 advanced
emergency medical facilities before the earthquake in
Miyagi Prefecture, now there are 71 facilities, as 4 of themwere shut down after the earthquake.
The population in demand is assumed as follows. First,
for the basic population data, the half grid regional square,with the length of each side about 500 m, in the national
population census, provided by the Ministry of Internal
Affairs and Communications Statistics Bureau, is used forthe population before the earthquake. For the data after theearthquake, the population of the area flooded by thetsunami is set as 0 for descriptive purposes while making acorrection reflecting the number of residents in temporary
housing. Also, within each grid, the location ofrepresentative points in each grid as the site of injury orillness is corrected by referring to the visible outline ofbuildings provided by the Geospatial Information Authorityof Japan.
For the road network, the numerical map 25000 from theyear 2002 was modified to create the original road network
data in the target analysis period of March 10, 2011 andMarch 11, 2012.
Based on these data, road distance was measured with
GIS, and the results were used to evaluate accessibility.
2. Results
The map of network distance before and after theearthquake is shown in figures 1 and 2. Naturally, areas
close to the hospitals have a short distance for accessibility,
while the accessibility decreases in areas far from thehospitals. The equidistance line is not in a simple circularform due to the drawing of the equidistance line by the road
network. The polygon drawn at 5 km equidistant of thehospitals on the Oshika Peninsula in Ishinomaki City andthe northwest edge of Miyagi Prefecture is more deformed
and punctured than the one for hospitals around Sendai
City. This is caused by the difference in maintenanceconditions of the road network in these areas. Especially on
the peninsula, areas with indentation and mountainous
areas tend to have a higher detour ratio, indicated by the
proportion of road distance to direct distance, thus
accessibility evaluation by road distance becomes moresignificant.
A comparison of accessibility before and after theearthquake reflects the considerable impact of the
shutdown of two facilities, the City of Ishinomaki Ogatsu
Hospital and Shizugawa Public Hospital, in the coastal
region in the north of Ishinomaki City. The urban areas inthis region are especially scattered due to the topographicalconstraint of ria coasts, and thus there is a decrease inaccessibility caused by the shutdown of one facility that

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Accessibility to medical care in case of major disasters

Figure 1

Figure 2

Figure 3

affects a large area. Although the City of Ishinomaki
Hospital, which used to be in a location overlooking
Ishinomaki Bay, has also been shut down due to damage by
the tsunami, the impact of decreased accessibility in thisarea can be considered small since the neighborhood
hospitals have been recovered.
A population histogram by distance zone is observed(see fig. 3). Before the earthquake, the number of people
that had access to the advanced emergency medical
facilities within 5 km was 1.82 million, or 77.1% of the total
population. After the earthquake, it was reduced by 67,000
people to 1.753 million, or 74.7% of the total population.
Between 5 km and 10 km, the number of people with accessFigure 4

was about 435,000 (about 18%) before the earthquake, andabout 453,000 (about 19%) after the earthquake.
Over 10 km, the number was 105,000 people (about 4.5%)
before the earthquake, and 142,000 people (about 6.0%)
after the earthquake. Over 30 km, the number was 560
people (0.02%) before the earthquake, and 2,459 people(0.10%) after the earthquake.
In general, the population histogram by distance zone
showed a decrease in accessibility despite the small amountof change.
The average distance and the maximum distance areshown in figure 4. Before the earthquake, the average
distance was 3.5 km, but it increased by 12% to 3.9 km after

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the earthquake. The maximum distance was 41.9 km for
both, and this did not change. The decrease in accessibility
was evident from the change in average distance.
3. Discussion
Multiple factors such as the change in population after
the earthquake, the decrease in hospitals due toearthquake damage, and the missing road network
contribute to the result of an over 10% increase in the
average distance after the earthquake. However, acomparison of network distance maps before and after theearthquake from figures 1 and 2 shows an obvious increasein the traveling distance around the medical facilities thatwere shut down. Therefore, it can be said that a decrease in
the number of medical facilities is a major cause of
decreased accessibility.
Also, the big increase in the population forced to travel along distance of over 10 km, 20 km, and 30 km is also anonnegligible factor in the event of a disaster. This
population is relatively small in the entire area. Moreover, atransportation route does not need to be limited to streets,since other modes, such as helicopter ambulance, can besuggested as an option if cost is left out of consideration.
However, this does not mean that the residents of suchareas can be ignored. In order to understand the problem,
it is important to study the residents in areas withsignificantly low accessibility in a quantitative way.
Therefore, the results of analysis for this section are
significant in that aspect.
This analysis is related to advanced emergency medical
facilities, and in the northern coastal region where urban
areas are scattered along a ria coast, a few cases were seen
where there was only one facility, so its shutdown affected alarge area. On the other hand, when assuming validation in
the category of a hospital instead of an advanced
emergency medical facility, the number of target facilities inthis region will likely increase. Due to the topographicalconstraints of this region, most functions tend to beconcentrated in the compact urban area. Even withincreased facilities, they will be damaged at the same time
as a result of concentrated function, and thus there is apossibility that substitutability cannot be guaranteed
despite the number of facilities. Robustness of accessibility,
which is measured by the availability of a second facility incase the first facility is not available for some reason, is
usually correlated with this substitutability. When functions
are concentrated for the previously described reason, therobustness of accessibility drops significantly. In otherwords, the robustness of accessibility for tsunami damage
is low in this region. Therefore, from the viewpoint of crisis
management, it is necessary to keep this factor in mind andconduct research on a placement system for medical
service hubs for other regions with the same topographic
features.

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The results of accessibility evaluation shown here arederived from all residents of Miyagi Prefecture as the
population in demand. Regarding population, although the
population change before and after the earthquake wasreflected in the analysis, this is not the population indemand in terms of the number of injured and ill people
who want to receive medical service at advanced
emergency medical facilities. For example, the degree ofdamage in the event of a disaster may differ by area, so it isimagined that the rate of demand occurrence changes
accordingly. Analyzing the number of injured and ill people
in the event of a disaster as population in demand will be anecessary task in the future for discussing crisis
management.
Furthermore, considering demand and supply of service
is a very significant issue in management discussions. The
next section will highlight this issue and proceed with ananalysis.

III. Efficiency improvement of thetransportation scenario
In the event of a disaster, it is expected that many people
will be injured and become ill at the same time. With therise of heavy demand, many injured and ill people will rush
to hospitals, which will cause hospitals to exceed theircapacity on the supply side. This can create a situation inwhich some injured and ill people are rejected by hospitals.
This means that not only “accessibility” but also“availability” of medical facilities become significant issues
in the event of emergency.
The important factor here is that each medical facility has
a capacity limit in accepting patients. The issue of capacityin each facility, which is probably not often a big problem inordinary times, will become more apparent during thekinds of emergency discussed in this paper. There is aproblem in how to define capacity. Also, a more realistic
problem is that capacity can change according to operating
policy and assessment of the situation by each facility.
However, while keeping such problems in mind, creating anaccessibility evaluation method that includes the capacity of
medical facilities is considered to contribute to discussionsof crisis management in the future.
Moreover, when the capacity of a facility is assumed inthis way, it no longer means that injured and ill people canreceive medical treatment by going to the closest facility.
Therefore, behavior becomes different and more
complicated from that discussed in section 2. Some people
will be able to receive medical treatment at the closest
facility, while others will only have their second- or thirdclosest facility available. Also, if it is not possible to predict
which facility is available, people are expected to show
behavior in which they will start searching from the closest
facility. Thus, based on various possibilities of behavior

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scenarios in transporting injured and ill people, this paper
suggests a method to improve transportation distance,
which is accessibility, by elaborating a transportation
scenario of injured and ill people and discussing its effect.
This is also considered to give valuable insight todiscussing crisis management from the viewpoint ofaccessibility to medical facilities.
1. Transporting injured and ill people
According to previous research [3], it is reported thattransporting injured and ill people at the time of the 2007
earthquake in Japan, 13% of victims were transported byambulance and 54% by general-purpose car. Although thisratio can change according to the type of disaster or thearea, it can be said that most transportation is by generalpurpose car.
When someone gets injured or falls ill and it is an urgent
situation, most people do not check the availability of the
medical facility they are heading to. If they are not acceptedby the medical facility after arriving there, they will thenhead to the next closest hospital from there. Suchtransportation behavior, in which people keep searching foran available hospital, can possibly happen.
Therefore, transportation by general-purpose car runs
the risk of increasing possibility of being rejected by
medical facilities due to lack of capacity. In order to avoid
this risk, it is efficient to pre-allocate hospitals for local
residents when they get injured or fall ill during an
emergency, although in reality this may not be absolutely
guaranteed. If a situation is established where hospitals canabsolutely accept patients, pre-allocating hospitals can savepeople from doing an unnecessary search, and thus will
reduce traveling distance in transportation.
Based on such notions, this paper assumes two types ofscenarios for transportation behavior of injured and ill
people in cases of emergency, which are “Search Scenario”
and “Pre-allocation Scenario,» and examines the differencein accessibility to advanced emergency medical facilities
based on these scenarios.
The details of the two scenarios are as follows. In the
Search Scenario, residents go to the closest hospital tosearch for availability. If they are rejected, they go to thenext closest hospital from there. In this scenario, thedistance becomes greater as they move every time they are

Figure 5rejected.
In the Pre-allocation Scenario, residents go to their preallocated hospitals. Specifically, the distance between an
accident site and all medical facilities is measured inadvance, and then a designated facility is determinedaccording to the rule of which person closest to the medical
facility has a higher priority in receiving medical care. Thisis different from the logic of minimizing transportation
distance for all injured and ill people. Traffic behavior
without complete information is expected in this scenario,
and thus it is extremely difficult in the event of a disaster.
However, this paper experimentally assumed this scenario
because of its simple logic and ease of program creation.
2. Analysis
The analysis time for this section was set as 1 year after
the earthquake. In order to discuss management right after
the earthquake, detailed data such as the situation of
medical facilities in operation or the number of injured andill people at that time were necessary. However, since suchdata were difficult to obtain, this paper set 1 year after theearthquake as the evaluation time. Therefore, from theperspective of how management should be implemented tocorrespond to a future disaster while the local
infrastructure is being repaired to a certain degree, theanalysis in this chapter verifies the effects of a guided
measure for transportation behavior. Although it is not acrisis management discussion in the event of a disaster, thiskind of review method can be applied to simulate a disasterevent.
The capacity, or acceptable number of patients, of eachhospital in Miyagi Prefecture is calculated by allocating thenumber of emergency care patients per day to each hospitalin accordance with the ratio of outpatients, which means
substituting it with the estimated allotment number for
emergency care per day in each hospital.
As in section 2 above, the site of injury or illness is thecorrected grid representative point. The number of people
in demand, which is the number of injured and ill people, isobtained as follows. First, the ratio of injured and ill people
is calculated by dividing the number of emergency care per
day by the population of Miyagi Prefecture. Then, tocalculate the number of injured and ill people in each grid,
the ratio of injured and ill people is multiplied by the
population in each grid. This number of the injured and ill is
only a temporary one based on the records for ordinary
times. Also, there are some reports indicating increased
emergency transportation after the earthquake, and thus
the estimated population in demand needs to bereconsidered in the future.
Using the data above, the final selection of hospitals andtransportation distance to reach them is obtained by the
program that assumes each scenario.
Figures 6 and 7 are accessibility maps based on each

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Figure 6

Figure 7

Figure 8

scenario. First, the Search Scenario map (fig. 6) shows astrong tendency for the distance to get shorter in the gridcloser to the hospitals. On the other hand, for the grid thatis far from the hospitals, some are rejected by nearby
hospitals, and thus there is an increase in traveling
distance. The risk of the Search Scenario, which is rejection
by hospitals, is captured visually in this map. Morespecifically, in some parts of the region surrounding
Minamisanriku Town in the northeast coastal area, thesuburban area of inland Osaki City, and the region
surrounding Kakuda City in the southeast coastal area,
repeating a search for hospitals can lead to traveling58

Figure 9

distance over 30 km.
As shown in the map for the Pre-allocation Scenario (fig.
7), because designated hospitals are allocated in advance,
the traveling distance for transportation tends to be shorter
than in the Search Scenario. Also, compared to the map for
the Search Scenario, it is evident that the area over 30 km
decreases dramatically in the map for the Pre-allocation
Scenario. Although there are some areas with increased
distances compared to the Search Scenario, the generaldecrease in traveling distance indicates improvement inaccessibility.
Second, the difference between accessibility in the two

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scenarios is examined through observing the population
histogram by distance zone (fig. 8). Within 0─5 km, there
are 44,000 people (62.4% of the total) for the Search
Scenario, and 46,000 people (65.3%) for the Pre-allocation
Scenario. There are more people in the Pre-allocation
Scenario than the Search Scenario. The same result isshown for the number of injured and ill people within 5─10km.
In the distance zone over 10 km, there are more people in
the Search Scenario than the Pre-allocation Scenario. The
total number of injured and ill people who were forced touse long-distance transportation of more than 10 km is
14,000 people (19.9% of the total) for the Search Scenario,
and 10,000 people (13.8%) for the Pre-allocation Scenario.
As shown here, the number of people in long-distancetransportation decreases in the Pre-allocation Scenario.
In figure 9, the maximum distance and the average
distance in each scenario are shown. For the average
distance, the Search Scenario is 7.2 km, and the Preallocation Scenario is 5.1 km; thus the Pre-allocation
Scenario is about 30% shorter than the Search Scenario. For
the maximum distance, the Search Scenario is 84.0 km, and
the Pre-allocation Scenario is 48.7 km; thus the Preallocation Scenario is about 42% shorter than the Search
Scenario.
From the viewpoint of securing accessibility to medical
services, it is an extremely important issue to decrease thenumber of injured and ill people in long-distancetransportation. In that regard, bringing a guided plan suchas the Pre-allocation Scenario is considered to be aneffective method.

and many more. Especially, this paper incorporated asimple logic in which the proximity to facilities determines
the priority of hospital choice in the Pre-allocation Scenario.
However, this logic could cause a disadvantage to residents
in areas that are forced to travel a long distance even in
ordinary times. Therefore, discussing a suitable logic forcrisis management, such as minimizing the total travel
distance or attempting to minimize the population in longdistance travel, will be a key factor for this simulation to
evolve.
Finally, the significance of accessibility evaluation withconsideration of capacity is discussed through comparisonof the results in section 2 and this section. From the results
in section 2, data after the earthquake are used to compare
the population ratio, average distance, and maximum
distance in each distance zone.
The population within 0─5 km is 74.7% if capacity is nottaken into account, but it is 62.4% in the Search Scenario
and 65.3% in the Pre-allocation Scenario, showing about 10%
difference. The population over 10 km is 6.0% without
consideration of capacity, 19.9% for the Search Scenario,
and 13.3% for the Pre-allocation Scenario, showing about 7─
14% difference as well. The average distance is 3.9 km, 7.2
km, and 5.1 km, respectively, while the maximum distanceis 41.9 km, 84.0 km, and 48.7 km, respectively, showing amajor difference. Even the demand is less than the supply
in total. When considering how to manage an individual
situation where demand exceeds capacity, which is crisis
management, the accessibility analysis method that takes
the capacity of a facility into account becomes necessary, as
suggested here.

3. Discussion
In this section, two types of transportation activity
scenarios were assumed, and the difference in accessibility
for each was discussed. As a result, the Pre-allocation
Scenario can accomplish a reduction in the averagetransportation distance by 30% compare to the Search
Scenario, indicating the great effectiveness of a guided planin improving accessibility for the time in which highdemand occurs all at once. For the maximum distance, agreater improvement effect was shown. Even for the
population who were forced to travel over 10 km, the Preallocation Scenario showed a reduction effect by 4,000
people (6%) compare to the Search Scenario. Therefore, inthe situation in which demand rises all at once, carrying out
this type of scenario is one effective management method.
On the other hand, there are many issues left in thisanalysis. Some are related to the precondition of
calculations, such as a method of determining capacity ateach hospital or a hypothesis method for the number of
injured and ill people, while others are concerned with away to choose a designated hospital in the Pre-allocation
Scenario, assuming behavior without complete information,

IV. Conclusion
In this paper, accessibility was evaluated and analyzed
from the viewpoint of road distance while assuming two
types of transportation behavior scenarios to examine ways
to improve efficiency in transportation behavior. It became
evident that: there is more than a 10% increase in the
average traveling distance after an earthquake; in an
emergency, when demand rises all at once and the capacityof facilities needs to be taken into account, transportation
distance increases compared to ordinary times, as somepeople may have to choose a facility at a distance; and aguided plan in which designated hospitals are pre-allocatedis clearly an effective way to improve accessibility.
However, some issues remain for the analysis method. In
reality, access to the medical care system should be
evaluated by time distance. Therefore, for more practicaland realistic analysis, it is necessary to make an analysis byincorporating data for multiple traffic speeds. Also, in order
to conduct more rigorous analysis for crisis management, it
is ideal to predict the population in demand more practicallyby incorporating logic that can anticipate a variable degree

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of crisis related to the area’s characteristics. Moreover,along with this prediction, it is necessary to develop amethod to evaluate the capacity of medical facilities.
Based on the improvement of these preconditions foranalysis, the research tasks ahead of this paper are: toassume sequentially occurring demands in the event of adisaster instead of only dealing with momentary demands;
and building a system to process demands on the time axis
that takes the passage of time and the capacity of facilities
into account.
Along with a community medical plan, public
administration and business operators dealing with medical
services are required to further discuss medical service
within a regional disaster prevention plan. For example, thetransportation plan for injured and ill people mentioned inthis paper is part of such a plan. As pointed out by theexisting research,5 after closely investigating the actual
condition of transporting injured and ill people by generalpurpose cars to build a transportation behavior model, it isan urgent issue to suggest a method of predicting thenumbers of injured and ill people along with atransportation plan as its dynamic. These are also otherresearch tasks of this paper for the future.

Acknowledgement
This research was financially funded by the Grant-in-Aid
for Scientific Research (KAKENHI) of Japan (Grant NO.
23249029).

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J. Natl. Inst. Public Health, 62（1）: 2013

Accessibility to medical care in case of major disasters

大規模災害発生時のケアへのアクセシビリティ
抄録
東日本大震災の発災当時，わが国ではその災害規模に対してしばしば想定外という言葉が用いられた．これに象徴されるように，これまでに積み重ねてきた防災・減災・事前復興というリスクマネジ
メントの概念による計画のみでは，大災害の備えとして十分でないことが明らかになる中で，クライシスマネジメントの視点から問題を再考することが，今後非常に重要になってくるだろうことは想像に難くない．
周知の通り，災害発生時には様々な地域施設へのアクセシビリティが低下し，災害の規模が大きいほど，その度合いは大きくなる．そして，供給量には上限があり，需要者全員がサービスを受けられない事態が容易に起こり得る．特に緊急時に需要が大量に発生する地域施設については，その影響の大きさを考慮して，どの程度の変化がどこで起こるのか，把握する手段を持つことが重要となる．医療は，災害発生時のような非常時において需要が高まるサービスの一つである．医療施設へのアクセ
シビリティが災害時にどのように変化するのか，そして医療サービスが受けられるか，つまり施設の
Availabilityは，現実的には非常に重要な問題になる．
そこで本稿では，災害発生時における医療施設へのアクセスに着目して，そのアクセシビリティがどのように変化するか検証する．また，災害時の傷病者搬送は一般車によるものが多数を占めることがわかっており，その実態を踏まえて搬送行動の在り方を考究する．具体的には，被災地の宮城県を舞台に，２次救急医療施設を対象として，震災前後のアクセシビリティ変化を分析するとともに，それら医療施設のキャパシティを想定し，傷病者が同時大量発生する際の受療可能施設へのアクセシビ
リ テ ィ の 分 析 を 行 う．分 析 に 際 し て は，ア ク セ シ ビ リ テ ィ を 道 路 距 離 と 読 み 替 え，geographic
information system（GIS）を用いて道路距離を計測した．
分析の結果，震災後の２次救急医療施設への平均移動距離は，震災前と比べて宮城県全体で１２％延びたこと，事前に割り当てられた病院に向かう誘導型施策に従えば，施設を探索して移動する行動と比べて３０％の移動距離短縮につながることが示された．
キーワード：災害，救急搬送，アクセシビリティ，道路距離，地理情報システム，宮城県
讃岐亮１），佐藤栄治２），熊川寿郎３），吉川徹１）
首都大学東京大学院都市環境科学研究科
２）
宇都宮大学大学院工学研究科
３）
国立保健医療科学院医療・福祉サービス研究部
１）

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