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This study establishes Markovian traffic equilibrium assignment based on the network generalized extreme value (NGEV) model, which we call NGEV equilibrium assignment. The use of the NGEV model for route choice modeling has recently been proposed, and it enables capturing the path correlation without explicit path enumeration. However, the theoretical properties of the model in traffic assignment have yet to be investigated in the literature, which has limited the practical applicability of the NGEV model in the traffic assignment field. This study addresses the research gap by providing the theoretical developments necessary for the NGEV equilibrium assignment. We first show that the NGEV assignment can be formulated and solved under the same path algebra as the traditional Markovian traffic assignment models. Moreover, we present the equivalent optimization formulations to the NGEV equilibrium assignment. The formulations allow us to derive both primal and dual types of efficient solution algorithms. In particular, the dual algorithm is based on the accelerated gradient method that is for the first time applied in the traffic assignment. The numerical experiments showed the excellent convergence and complementary relationship of the proposed primal-dual algorithms., Comment: 37 pages, 14 figures

This study aims to analyze the relationship between a macroscopic fundamental diagram (MFD), which relates vehicle accumulation with throughput at the network level, and the spatial distribution of congestion (congestion pattern) in a general network with one-to-many origin-destination demands. In particular, we clarify the causes of a decreasing branch of MFDs and the influence of local signal controls on the (global) network throughput. For this aim, we present a new inverse problem of the dynamic user equilibrium assignment by using a periodic boundary condition, and an analytical formula of the network throughput for a fixed accumulation is derived by solving it. This enables us to incorporate the effects of network configurations and route choice behaviors into the analysis of the network throughput. By conducting a sensitivity analysis of this formula, we identify the types of congestion patterns that cause the decrease in the network throughput and examine a network signal control for improving network performance.

This study investigates dynamic system-optimal (DSO) and dynamic user equilibrium (DUE) traffic assignment of departure/arrival-time choices in a corridor network. The morning commute problems with a many-to-one pattern of origin-destination demand and the evening commute problems with a one-to-many pattern are considered. Specifically, a novel approach to derive closed-form solutions for both DSO and DUE problems is developed. We first derive a closed-form solution to the DSO problem based on the regularities of the cost and flow variables at an optimal state. By utilizing this solution, we prove that the queuing delay at a bottleneck in a DUE solution is equal to an optimal toll that eliminates the queue in a DSO solution under certain conditions of a schedule delay function. This enables us to derive a closed-form DUE solution by using the DSO solution. We also show the theoretical relationship between the DSO and DUE assignment. Numerical examples are provided to illustrate and verify the analytical results., Comment: 34 pages, 14figures

This paper studies the social acceptability and feasibility of a focused protection strategy against coronavirus disease 2019 (COVID-19). We propose a control scheme to develop herd immunity while satisfying the following two basic requirements for a viable policy option. The first requirement is social acceptability: the overall deaths should be minimized for social acceptance. The second is feasibility: the healthcare system should not be overwhelmed to avoid various adverse effects. To exploit the fact that the disease severity increases considerably with age and comorbidities, we assume that some focused protection measures for those high-risk individuals are implemented and the disease does not spread within the high-risk population. Because the protected population has higher severity ratios than the unprotected population by definition, the protective measure can substantially reduce mortality in the whole population and also avoid the collapse of the healthcare system. Based on a simple susceptible-infected-recovered model, social acceptability and feasibility of the proposed strategy are summarized into two easily computable conditions. The proposed framework can be applied to various populations for studying the viability of herd immunity strategies against COVID-19. For Japan, herd immunity may be developed by the proposed scheme if $${\mathcal {R}}_0 \le 2.0$$ R 0 ≤ 2.0 and the severity rates of the disease are 1/10 times smaller than the previously reported value, although as high mortality as seasonal influenza is expected.

This paper presents a systematic approach for analyzing the departure-time choice equilibrium (DTCE) problem of a single bottleneck with heterogeneous commuters. The approach is based on the fact that the DTCE is equivalently represented as a linear programming problem with a special structure, which can be analytically solved by exploiting the theory of optimal transport combined with a decomposition technique. By applying the proposed approach to several types of models with heterogeneous commuters, it is shown that (i) the essential condition for emerging equilibrium "sorting patterns," which have been known in the literature, is that the schedule delay functions have the "Monge property," (ii) the equilibrium problems with the Monge property can be solved analytically, and (iii) the proposed approach can be applied to a more general problem with more than two types of heterogeneities., 42 pages, 10 figures

This paper studies the social acceptability and feasibility of “herd immunity” strategies against coronavirus disease 2019 (COVID-19). To this end, we propose a control scheme that aims to develop herd immunity while satisfying the following two basic requirements for a viable policy option. The first requirement is social acceptability: the overall deaths should be minimized for social acceptance. The second is feasibility: the healthcare system should not be overwhelmed to avoid diverse adverse effects. Exploiting the fact that the severity of the disease increases considerably with age, the proposed control scheme protects high-risk individuals that mainly consist of the elderly. The protection of high-risk individuals reduces the average severity of the disease in the unprotected population, thereby substantially reducing mortality and avoiding the collapse of the healthcare system. Social acceptability (in terms of the resulting mortality) and feasibility (in terms of the healthcare system capacity) of the proposed herd immunity strategy are summarized into two respective, easily computable conditions by building on a simple susceptible–infected–recovered (SIR) model. For its parsimony, the proposed framework can provide a rule of thumb that applies to various populations for studying the viability of herd immunity strategies against COVID-19. For Japan, herd immunity may be developed by the considered control scheme ifand the severity rates of the disease are 1/10 times smaller than the previously reported value, although as high mortality as seasonal influenza is expected.

Akamatsu et al. (2006) proposed a new transportation demand management scheme called “tradable bottleneck permits” (TBP), and proved its efficiency properties for a single bottleneck model. This paper explores the properties of a TBP system for general networks. An equilibrium model is first constructed to describe the states under the TBP system with a single OD pair. It is proved that equilibrium resource allocation is efficient in the sense that the total transportation cost in a network is minimized. It is also shown that the “self-financing principle” holds for the TBP system. Furthermore, theoretical relationships between TBP and congestion pricing (CP) are discussed. It is demonstrated that TBP has definite advantages over CP when demand information is not perfect, whereas both TBP and CP are equivalent for the perfect information case. Finally, it is shown that the efficiency result also holds for more general demand conditions.

This study examines the properties of equilibrium, including the stability, of discrete-space agglomeration models with social interactions. The findings reveal that while the corresponding continuous-space model has a unique equilibrium, the equilibrium in discrete space can be non-unique for any finite degree of discretization by characterizing the discrete-space model as a potential game. Furthermore, it indicates that despite the above result, any sequence of discrete-space models’ equilibria converges to the continuous-space model’s unique equilibrium as the discretization of space is refined.

The mechanism of self-organization of agglomerations in a long narrow economy of a new economic geography model is elucidated by a theoretical comparative study with a racetrack economy. Computational bifurcation theory is used to systematically obtain the equilibria of these economies. A chain of spatially repeated core–periphery patterns a la Christaller and Losch emerges when agglomeration forces are large. Peripheral zones are enlarged recurrently to engender an agglomeration shadow en route to an atomic mono-center. A megalopolis with two core places connected by an industrial belt emerges when agglomeration forces are small.

We study a parsimonious theory that synthesizes short-term traffic demand management (TDM) policies with long-term endogenous heterogeneities of demand. In a corridor network with multiple discrete bottlenecks, we study a model of system optimal assignment that integrates the short-term problem (departure time choice with tolling) and the long-term problem (job and residential location choice). For the short-term departure-time-choice equilibrium, under mild assumptions on schedule delay function, we derive analytical solutions under a first-best TDM scheme. Investigating properties of long-term equilibria, we found that the overall equilibrium pattern exhibits remarkable spatio-temporal sorting properties. It is further shown that a lack of integration of the short- and the long-term policy results in excessive investments for long-term road construction.

Harris and Wilson (1978)’s retail location model is one of the pioneering works in regional sciences. This model considers the combination of the “fast” and “slow” dynamics to describe spontaneous spatial pattern formation processes in the economic landscape. Although the model was proposed some time ago, its comparative static (bifurcation) properties have not yet been sufficiently explored. We employ a simple analytical approach developed by Akamatsu et al. (2012) to reveal previously unknown bifurcation properties of the model in a space with a large number of locations. It is analytically shown that the spatial structure’s evolutionary path exhibits a remarkable property, namely a “spatial period-doubling cascade,” which cannot be observed in the popular two-location setup. Furthermore, we discuss strong linkages between the model and “new economic geography” models in terms of their model structures and bifurcation properties. These results offer a new theoretical perspective for understanding agglomeration and spatial structure evolution.

Using the theory of potential games, this paper addresses the emergence of polycentric structures in cities that result from trade-offs between agglomeration economies and congestion effects. We consider a model that explains the formation of multiple business centers in cities as an equilibrium outcome under the presence of households' commuting costs and positive technological externalities between firms. We show that the model is a large-population (non-atomic) potential game. To elucidate properties of stable spatial equilibria in the model, we consider local and global maximizations of the potential function, which are known to correspond to various equilibrium refinement criteria. We find that (i) the formation of business centers (agglomeration of firms) is possible only when households' commuting costs are sufficiently low and that (ii) the size (number) of business centers increases (decreases) monotonically as communication between firms becomes easier.

Industrial yeast strains with good xylose fermentation ability and inhibitor tolerance are important for economical lignocellulosic bioethanol production. The flocculating industrial Saccharomyces cerevisiae strain NAPX37, harboring the xylose reductase-xylitol dehydrogenase (XR-XDH)-based xylose metabolic pathway, displayed efficient xylose fermentation during batch and continuous fermentation. During batch fermentation, the xylose consumption rates at the first 36 h were similar (1.37 g/L/h) when the initial xylose concentrations were 50 and 75 g/L, indicating that xylose fermentation was not inhibited even when the xylose concentration was as high as 75 g/L. The presence of glucose, at concentrations of up to 25 g/L, did not affect xylose consumption rate at the first 36 h. Strain NAPX37 showed stable xylose fermentation capacity during continuous ethanol fermentation using xylose as the sole sugar, for almost 1 year. Fermentation remained stable at a dilution rate of 0.05/h, even though the xylose concentration in the feed was as high as 100 g/L. Aeration rate, xylose concentration, and MgSO4 concentration were found to affect xylose consumption and ethanol yield. When the xylose concentration in the feed was 75 g/L, a high xylose consumption rate of 6.62 g/L/h and an ethanol yield of 0.394 were achieved under an aeration rate of 0.1 vvm, dilution rate of 0.1/h, and 5 mM MgSO4. In addition, strain NAPX37 exhibited good tolerance to inhibitors such as weak acids, furans, and phenolics during xylose fermentation. These findings indicate that strain NAPX37 is a promising candidate for application in the industrial production of lignocellulosic bioethanol.

This paper presents a transparent approach to the analysis of dynamic user equilibrium and clarifies the properties of a departure- time choice equilibrium of a corridor problem where discrete multiple bottlenecks exist along a freeway. The basis of our approach is the transformation of the formulation of equilibrium conditions in a conventional “Eulerian coordinate system” into one in a “Lagrangian-like coordinate system.” This enables us to evaluate dynamic travel times easily, and to achieve a deep understanding of the mathematical structure of the problem, in particular, about the properties of the demand and supply (queuing) sub-models, relations with dynamic system optimal assignment, and differences between the morning and evening rush problems. Building on these foundations, we establish rigorous results on the existence and uniqueness of equilibria.

Continuous fermentation using the industrial Saccharomyces cerevisiae diploid strain WW was carried out under acidic or high-temperature conditions to achieve acid- or thermo-tolerant mutants. Mutants isolated at pH 2.5 and 41°C showed improved growth and fermentation ability under acidic and elevated temperature conditions. Haploid strains WW17A1 and WW17A4 obtained from the mutated diploid strain WW17A showed better growth and 4.5-6.5% higher ethanol yields at pH 2.7 than the original strains. Haploid strain WW12T4 obtained from mutated diploid strain WW12T showed 1.25-1.50 times and 2.8-4.7 times higher total cell number and cell viability, respectively, than the original strains at 42°C. Strain AT, which had significantly improved acid- and thermo-tolerance, was developed by mating strain WW17A1 with WW12T4. Batch fermentation at 41°C and pH 3.5 showed that the ethanol concentration and yield achieved during fermentation by strain AT were 55.4 g/L and 72.5%, respectively, which were 10 g/L and 13.4% higher than that of the original strain WW. The present study demonstrates that continuous cultivation followed by haploidization and mating is a powerful approach for enhancing the tolerance of industrial strains.

Self-organization of agglomeration patterns for economic models in a two-dimensional economic space is studied from a multi-disciplinary viewpoint of new economic geography, central place theory, and bifurcation theory. Emergence of hexagonal distributions of various sizes in a homogeneous space is predicted theoretically for core–periphery models. The existence of hexagonal distributions as stable equilibria is demonstrated by a comparative static analysis with respect to transport costs for specific core–periphery models. These distributions are the ones envisaged by central place theory and also inferred to emerge by Krugman (1996) for a core–periphery model in two dimensions.

We screened an industrial thermotolerant Saccharomyces cerevisiae strain, KF7, as a potent lactic-acid-assimilating yeast. Heterothallic haploid strains KF7-5C and KF7-4B were obtained from the tetrads of the homothallic yeast strain KF7. The inefficient sporulation and poor spore viability of the haploid strains were improved by two strategies. The first strategy was as follows: (i) the KF7-5C was crossed with the laboratory strain SH6710; (ii) the progenies were backcrossed with KF7-5C three times; and (iii) the progenies were inbred three times to maintain a genetic background close to that of KF7. The NAM12 diploid between the cross of the resultant two strains, NAM11-9C and NAM11-13A, showed efficient sporulation and exhibited excellent growth in YPD medium (pH 3.5) at 35°C with 1.4-h generation time, indicating thermotolerance and acid tolerance. The second strategy was successive intrastrain crosses. The resultant two strains, KFG4-6B and KFG4-4B, showed excellent mating capacity. A spontaneous mutant of KFG4-6B, KFG4-6BD, showed a high growth rate with a generation time of 1.1 h in YPD medium (pH 3.0) at 35°C. The KFG4-6BD strain produced ascospores, which were crossed with NAM11-2C and its progeny to produce tetrads. These tetrads were crossed with KFG4-4B to produce NAM26-14A and NAM26-15A. The latter strain had a generation time of 1.6 h at 35°C in pH 2.5, thus exhibiting further thermotolerance and acid tolerance. A progeny from a cross of NAM26-14A and NAM26-15A yielded the strain NAM34-4C, which showed potent lactic acid assimilation and high transformation efficiency, better than those of a standard laboratory strain.

The lactic acid-assimilating yeast Saccharomyces cerevisiae NAM34-4C grew rapidly in minimal D-lactate medium (pH 3.5) at 35°C, compared with minimal L-lactate medium. A laboratory strain, S. cerevisiae S288C, did not grow in either medium at pH 3.5. Strain NAM34-4C produced remarkably high levels of ethanol in YPDL medium at pH 3.5, but not at pH 5.5, when D-lactate was provided as the carbon source. Optimal cultivation conditions for ethanol production from D-lactate by strain NAM34-4C were as follows: shaking speed, 60 rpm; initial pH, 3.0; cultivation temperature, 35°C; yeast extract, 5 g/L; peptone, 10 g/L; and D-lactate, 30 g/L. Under these conditions, strain NAM34-4C produced 2.7 g/L ethanol, which is 18% of the theoretical maximal yield (0.51 3 initial D-lactate concentration).

In this study, we analyzed the actual amount of gasoline transported into the Tohoku region during the first month after the Great East Japan Earthquake. We found that: (1) the amount of gasoline supplied in the Tohoku region during the first two weeks was only 1/ 3 of the normal demand; (2) the shortage of supply in the first two weeks led to a huge “back-log of demand”; (3) it took four weeks for the backlog to be cleared and the lost (suppressed) demand during the period was equivalent to the amount of normal demand for 7 days; (4) the gaps between gasoline supply and demand in the Pacific coast areas were huge, compared with those in the Japan sea coast areas, while the gap in each prefecture of the Tohoku region was gradually reduced over time in the following order: Akita, Aomori, Iwate, Yamagata, and finally, Miyagi prefecture.

We provide an analytical approach that facilitates understanding the bifurcation mechanism of a wide class of economic models involving spatial agglomeration of economic activities. The proposed method overcomes the limitations of the Turing (1952) approach that has been used to analyze the emergence of agglomeration in the multi-regional core-periphery (CP) model of Krugman (1993, 1996). In other words, the proposed method allows us to examine whether agglomeration of mobile factors emerges from a uniform distribution and to analytically trace the evolution of spatial agglomeration patterns (i.e., bifurcations from various polycentric patterns as well as a uniform pattern) that these models exhibit when the values of some structural parameters change steadily. Applying the proposed method to the multi-regional CP model, we uncover a number of previously unknown properties of the CP model, and notably, the occurrence of “spatial period doubling bifurcation” in the CP model is proved.

The progress of spatial agglomeration of Krugman's core–periphery model is investigated by comparative static analysis of stable equilibria with respect to transport costs. We set forth theoretically possible agglomeration (bifurcation) patterns for a system of cities spread uniformly on a circle. A possible and most likely course predicted is a gradual and successive one, which is called spatial period doubling. For example, eight cities concentrate into four cities and then into two cities en route to the formation of a single city. The existence of this course is ensured by numerical simulation for the model. Such a gradual and successive agglomeration presents a sharp contrast to the agglomeration of two cities, for which spontaneous concentration to a single city is observed in core–periphery models of various kinds. Other bifurcations that do not take place in two cities, such as period tripling, are also observed. The need for study of a system of cities has thus been demonstrated.

To clarify the mechanisms of xylitol utilization, three xylitol-assimilating mutants were isolated from recombinant Saccharomyces cerevisiae strains showing highly efficient xylose-utilization. The nucleotide sequences of the mutant genomes were analyzed and compared with those of the wild-type strains and the mutation sites were identified. gal80 mutations were common to all the mutants, and recessive to the wild-type allele. Hence we constructed a gal80Δ mutant and confirmed that the gal80Δ mutant showed a xylitol-assimilation phenotype. When the constructed gal80Δ mutant was crossed with the three isolated mutants, all diploid hybrids showed xylitol assimilation, indicating that the mutations were all located in the GAL80. We analyzed the role of the galactose permease Gal2, controlled by the regulatory protein Gal80, in assimilating xylitol. A gal2Δ gal80Δ double mutant did not show xylitol assimilation, whereas expression of GAL2 under the control of the TDH3 promoter in the GAL80 strain did result in assimilation. These data indicate that Gal2 was needed for xylitol assimilation in the wild-type strain. When the gal80 mutant with an initial cell concentration of A660 = 20 was used for batch fermentation in a complex medium containing 20 g/L xylose or 20 g/L xylitol at pH 5.0 and 30°C under oxygen limitation, the gal80 mutant consumed 100% of the xylose within 12 h, but

Involvement of the Bacillus subtilis ABC transporter EcsB in genetic transformation with native DNA from protoplast lysate (LP transformation) was investigated using an ecsB deletion mutant constructed by fusion polymerase chain reaction. In these experiments, the non-transformability phenotype of the ecsB mutant was reversed and high numbers of transformants generated (1.5×10(5)/μg DNA). The relative efficiency of transformation (RET) of ecsB to wild type (1.2×10(-2)) was a thousand times higher using native chromosomal DNA than the RET obtained from purified DNA (

The roles of ComFA and ComEC in DNA uptake by competent Bacillus subtilis were analyzed by transformation with DNA in protoplast lysates (LP transformation). Deletion mutants of comFA and comEC and putative Walker A mutants (K152N, K152Q, K152E) of comFA were constructed by fusion polymerase chain reaction. Transformants of comEC mutant with purified DNA and DNA in protoplast lysate were not obtained, which shows a lack of transformation ability and backwards recombination of the mutant. Transformants of the comFA mutant were obtained by LP transformation (1.8 × 10 4 transformants/μg DNA). Low relative efficiency of transformation (RET) of comFA compared to wild type (4.3 × 10 − 4 ) showed an important role for comFA in DNA uptake. Walker A mutants showed 1.8–19 × 10 − 4 RET, suggesting a dependence on ATPase activity for transformation. Co-transformation between short linkages was only detected in comFA mutants. The results demonstrated that ComFA controlled the DNA uptake rate. The interpretation was further supported by analyzing the plasmid used in LP transformation of the comFA mutant. The RET of comFA compared to the wild type was 2.7 × 10 − 2 , 60-fold higher than that with chromosomal DNA (4.3 × 10 − 4 ). Following addition of DNA into comFA culture, transformants were obtained after 15 min, with the number of transformants increasing over time. The kinetics strongly suggested that in comFA mutants, formation of another DNA uptake complex without ComFA would be a lengthy process.

本研究は，一般的な構造を持つ道路ネットワークを対象に，ネットワーク通行権取引市場のオークション・メカニズムを設計する．提案メカニズムの目的は，実装が容易かつ情報交換量の観点から効率的な方法で，ネットワーク容量の効率的配分を達成することである．そのために，本研究では，day-to-dayアプローチを採用する．そして，提案メカニズムが次に示す望ましい性質を満たすことを明らかにする：(1)利用者の正直な入札は支配戦略である，(2)提案メカニズム導入下の通行権配分パターンは，有限回で（近似的な）社会的最適状態へと到達し，このとき達成される社会的余剰は，利用者数が十分大きい場合，厳密に最大化される．

都市経済学分野では，複数都心の形成現象は，複数種類の経済主体(e.g.消費者と企業)が土地市場で競合する場合のみ起こると考えられてきた(Fujita and Thisse, 2002, p.209) ．本研究では，単一種類の立地主体しか持たないモデルでも複数都心が創発しうることを，Beckmann型Social Interaction (SI) モデルを例として，明らかにする．さらに，複数都心が創発するための鍵となる条件は，spill over効果のある分散力と，その距離減衰性であることを示す．これを示すために，地代による分散力が働くBeckmann型モデル(SIモデル)と空間競争による分散力が働くBeckmann型モデル(SISCモデル)を対比的に分析する．そして，SIモデルでは単一都心しか創発しない一方，SISCモデルでは複数都心が創発することを明らかにする．

本研究は，新経済地理学(NEG)分野で開発された2都市 Core-Periphery (CP)モデルを多都市システムの枠組に拡張し，その均衡解の分岐(少数都市への産業・人口集積)特性を明らかにする．CPモデルに関する従来研究は，その大半が2都市モデルの解析に留まっている．その最大の理由は，多都市モデルで生じる分岐解析の困難さにある．この問題に対し，本稿は，空間割引行列，離散フーリエ変換，円周都市システムの3つの鍵概念を組合わせたアプローチを提示する．そして，その分析法を用いれば，多都市CPモデルにおける分岐の基本的な仕組みは容易に理解できることが示される．さらに，計算分岐理論に基づいた系統的な数値計算により，より詳細な集積・分散パターンも明らかにされる．

都市経済学分野では，Beckmann3)を先駆として，「都心形成」現象を説明する研究が蓄積されてきた．しかし，これらの既存研究では，均衡解の一意性・安定性を全く議論しておらず，均衡状態・社会的最適状態ともに，対称な立地パターンを前提として分析している．そこで，本研究では，Beckmannモデルの均衡解の一意性・安定性を確認する方法を示した．その方法を利用することで，Beckmannモデルの均衡解が一般的に一意ではなく，既存研究で知られる対称な立地パターン以外に，非対称な均衡立地パターンが存在することを明らかにした．さらに，均衡状態では，対称な立地パターンより，非対称な立地パターンの方が効率的であることを数値実験により確認した．

本研究は，“交通渋滞 (queuing congestion)”と“交通混雑 (flow congestion)”の2種類の経済外部性を解消し，かつ詳細な利用者情報を必要としない交通需要管理スキームを提案する．これは近年，ITSを活用した近未来型交通制度として提案された“ボトルネック通行権取引制度 (TBP)”を拡張したものである．TBPに関するこれまでの研究では，交通混雑を考慮しておらず，またマイクロ・メカニズムは明らかにされていない．そこで，本稿では，交通混雑を明示的に扱い，提案スキームのマイクロ・メカニズムをオークション理論及び，進化・学習ゲーム理論に基づき構築する．そして，提案スキーム導入下のマクロな交通流パターンが，社会的交通費用が最小となる社会的最適状態へと収束することを明らかにする．

都市経済学における標準的な住宅立地理論は，交通費用と地代のトレード・オフ関係をもとに，都市の土地利用と交通パターンを説明する．その理論では，交通条件は静学的な枠組みで表現され，渋滞現象等のintra-dayレベルの詳細は無視できると仮定されている．一方，ボトルネック・モデルに関する最近の研究によれば，静学的な交通モデルは，交通費用に関して非常に大きな評価誤差を生じうると指摘されている．そこで，本研究では，従来の立地−交通均衡理論が，どのような都市条件の下で，交通費用に関して大きなバイアスを生むかを明らかにする．この目的を達成するために，本研究では，通勤者の出発時刻選択を内生化した住居立地モデルを構築し，均衡解を求める．そして，その均衡解から，従来理論による状態表現が妥当でないと考えられる都市−交通条件を導く．