A multi-layer scenario analysis for sustainable international transport

This article considers the development of the international transport sector based on four globalization scenarios. These four images of the future transportation market are constructed at three different levels (global, European and Dutch). The possible consequences of these scenarios are mapped out not only by key aspects such as modal split and spatial organization but also by providing empirical insights into expected transport flows for both passenger and freight transport in 2020 based on data from 1995.     

轿车内部凸出物试验方法

为加强车内乘员保护,进一步改善和优化汽车仪表板及结构部件设计,文章通过分析汽车内部凸出物标准有关技术要求,探讨了相关试验方法,通过不同试验方法对比得出了试验设备与实际测量碰撞点空间位置重合法,能更好地模拟乘员在事故中的碰撞;该方法能更好地考核乘员在事故中受到的伤害,同时能更好地验证仪表板及其结构部件的质量。因此,建议试验机构或生产厂家应按照该方法进行汽车内部凸出物静态吸能试验。     

Jobs-housing imbalance, spatial correlation, and excess commuting

In this paper, we use continuous urban structure instead of zonal model, try to calculate unbiased excess commuting with joint distribution of homes and workplaces developed by Vaughan (1974), and describe the relationship between urban structure and commuting distance explicitly and theoretically for generalized home-workplace assignment pattern. We simplify the quadrivariate distribution model to a model with three important parameters: the spread of homes, the spread of workplaces, and the spatial correlation of homes and workplaces. Then we show that excess commuting and capacity utilization are expressed by the imbalance and the spatial correlation of jobs-housing structure in a theoretical context, moreover it explicitly evaluates targeting US and Japanese/Korean cities.     

The maximum approximate composite marginal likelihood (MACML) estimation of multinomial probit-based unordered response choice models

The likelihood functions of multinomial probit (MNP)-based choice models entail the evaluation of analytically-intractable integrals. As a result, such models are usually estimated using maximum simulated likelihood (MSL) techniques. Unfortunately, for many practical situations, the computational cost to ensure good asymptotic MSL estimator properties can be prohibitive and practically infeasible as the number of dimensions of integration rises. In this paper, we introduce a maximum approximate composite marginal likelihood (MACML) estimation approach for MNP models that can be applied using simple optimization software for likelihood estimation. It also represents a conceptually and pedagogically simpler procedure relative to simulation techniques, and has the advantage of substantial computational time efficiency relative to the MSL approach. The paper provides a “blueprint” for the MACML estimation for a wide variety of MNP models.     

电子海图空间数据索引结构及检索算法研究

电子海图系统是一种信息显示系统,电子海图数据的格式种类繁多,为使系统支持不同格式的海图数据、实现通用性,提出一种具有一定适应能力的空间数据索引结构,该结构能访问已有的大多数海图格式。另外提出建立区间分解检索机制,采用B 树结构快速搜索出满足用户要求的海图。最后针对海图显示速度慢的问题,引入位映像图检索算法以提高显示速度。     

Transit oriented development and retail: Is variation in success explained by a gap between theory and practice?

Central to the concept of Transit Oriented Development (TOD) is a retail core situated around stations. However, successful retail near light rail transit stations has been elusive. Despite significant implications for land use, transportation, and economic development planning, little research exists to explain the gap between TOD concept and reality. We hypothesize that the density, diversity, and design characteristics central to the theory of TODs drive retail success. We implement a TOD Index proposed in the literature to score 474 light rail station areas in 11 metropolitan areas according to the presence and magnitude of those density, diversity, and design characteristics. A series of robustly-developed multilevel models support our hypothesis: TOD Index scores significantly predict station area retail employment, ceteris paribus. An evaluation of its subcomponents individually (block size, which relates to walkability; land use mix; and activity density) suggests activity density may be the driving force in this relationship. Our research works to move the conversation away from an assumption that transit stations and retail naturally co-exist and toward more intentional station area design choices demonstrated to drive retail employment.     

The value of transportation accessibility in a least developed country city – The case of Rajshahi City,Bangladesh

Little appears to be known about the capitalization of transportation accessibility in South Asian housing markets, which typically differ from those of industrialized countries. This study starts addressing this gap by providing empirical evidence about the nature and the magnitude of the value of accessibility as reflected by residential rents in Rajshahi City, Bangladesh. Results of our SARAR spatial hedonic model estimated on 526 observations from a random sample collected via in-person interviews indicate that the rent of a multi-unit dwelling decreases by 0.0239% for every 1% increase in network access distance to the nearest major road. Moreover, proximity (within 400 m) to a primary school and to a healthcare facility commands rent premiums of respectively 93.55 BDT ($1.40) and 109.45 BDT ($1.64). Surprisingly, whether access roads are paved or not does not statistically impact rents, probably because of the dominance of walking, rickshaws use, and biking, combined with the rarity of personal cars. Likewise, proximity to bus stops and to train stations is not reflected in rents of multi-family dwellings, likely because buses and trains in Rajshahi City only provide regional and national service. Differences in estimates of our spatial models between maximum likelihood (ML) and generalized spatial two-stage-least-squares illustrate the danger of relying on ML in the presence of heteroskedasticity. These results should be useful for planning transportation infrastructure funding measures in least developed country cities like Rajshahi City.