A structural and empirical model of subsistence activity behavior and income

This paper develops a structural and empirical model of subsistence activity behavior and income. Subsistence activity decisions (work participation and hours of work decisions) and income have an important bearing on activity and travel behavior of individuals. The proposed structural model represents an effort to analyze subsistence activity behavior and income earnings to support a better understanding, and reliable forecasting, of individual travel behavior. The empirical model formulates and estimates an integrated model of employment, hours of work and income which takes account of interdependencies among these choices and their structural relationships with other relevant variables. Social factors that inhibit an individual's employment and work hours decision and affect an individual's income are incorporated in the model. A sample of households from the Dutch National Mobility Panel is used in the empirical analysis.     

A model of joint activity participation between household members

A proportional shares model of daily time allocation is developed and applied to the analysis of joint activity participation between adult household members. The model is unique in its simultaneous representation of each decision maker's decisions concerning independent activity participation, allocation of time to joint activities, and the interplay between individual and joint activities. Further, the model structure ensures that predicted shares of joint activity outcomes be the same for both decision makers, an improvement over models that do not make interpersonal linkages explicit. The empirical analysis of travel diary data shows that employment commitments and childcare responsibilities have significant effects on tradeoffs between joint and independent activities. In addition, evidence is presented for the continued relevance of gender-based role differences in caring for children and employment participation.     

环球竞赛号机动船创最新环游地球纪录

装备两台康明斯-水星QSC型8.3升540马力全电控船用发动机、燃用B100生物柴油(100%的生物柴油)的"环球竞赛号(Earthrace)"高速环保机动船6月27日抵达西班牙萨贡托     

Uncertainty in traffic forecasts: literature review and new results for The Netherlands

This paper provides a review of transport model applications that not only provide a central traffic forecast (or forecasts for a few scenarios), but also quantify the uncertainty in the traffic forecasts in the form of a confidence interval or related measures. Both uncertainty that results from using uncertain inputs (e.g. on income) and uncertainty in the model itself are treated. The paper goes on to describe the methods used and the results obtained for a case study in quantifying uncertainty in traffic forecasts in The Netherlands.

Transportation and land-use preferences and residents’ neighborhood choices: the sufficiency of compact development in the Atlanta region

This paper analyzes the transportation and land-use preference and actual neighborhood choices of a sample of 1,455 residents of metro Atlanta. We develop a stated-preference scale on which desires for neighborhood type are gauged, from preferences for low-density, auto-oriented environments to desires for compact, walkable, and transit-oriented neighborhoods. This scale is then related to desires for change in one’s own neighborhood characteristics after a hypothetical move. If all neighborhood preferences were equally likely to be satisfied, then neighborhood preferences would not be correlated with a desire for change. By contrast, in the current study, stronger preferences for a more walkable environment are associated with greater desire for change in one’s neighborhood characteristics. This suggests an undersupply of compact, walkable, and transit-friendly neighborhood types relative to current demand.

新纪录 新总裁——美国康明斯公司迎来新时代

康明斯上半年业绩再创历史新高 康明斯公司日前发布二季度财务公报，销售额和利润均创历史最高纪录，美国以外海外市场的迅猛增势有效抵御了美国经济疲软带来的负面影响。本季度国际业务额占康日月斯全球销售的比重持续攀升，从上季度的57％增至二季度的61％，2007年海外业务的比重则是54％．显示康明斯多元化的全球市场战略继续发挥至关重要的作用。     

不确定的未来——2014上半年南非商用车市场分析

南非商用车市场2014上半年的销售让人印象深刻,但是,在劳工运动对汽车制造商持续产生影响的形势下,我们不禁要问,接下来的市场还能迎来上升吗？本文主要分析了2014年第2季度（4-6月）车辆总质量（gross vehicle mass,GVM）为3.5 t以上的南非商用车市场情况,以季度为时间单位是为了减少一些短期内市场行为的影响,比如,大批量交货、推出新产品、旧产品系列淘汰,等等.     

Defining and understanding trip chaining behaviour

Trip chaining is a phenomenon that we know exists but rarely investigate. This could be attributed to either the difficulty in defining trip chains, extracting such information from travel diary surveys, the difficulty in analysing all the possible trip chain types, or all of the above. Household travel diary surveys provide a wealth of information on the travel patterns of individuals and households. Since such surveys collect all information related to travel undertaken, in theory it should be possible to extract trip-chaining characteristics of travel from them. Due to the difficulty in establishing and analysing all of the possible trip chain types, the majority of research on trip chaining has appeared to focus on work travel only. However, work related travel in many cities does not represent the majority of activities undertaken and, for some age groups, does not represent any travel at all. This paper begins by reviewing existing research in the field of trip chaining. In particular, investigations into the definitions of trip chaining, the defined typologies of trip chains and the research questions that have been addressed are explored. This review of previous research into trip chaining facilitates the following tasks: the identification of the most useful questions to be addressed by this research; defining trip chaining and associated typologies and defining data structures to extract trip chaining information from the household travel surveys conducted in metropolitan Adelaide, South Australia. The definition and typology developed in our research was then used to extract trip-chaining information from the household travel diary survey (MAHTS99) conducted in Adelaide in 1999. The extracted trip chaining information was then used to investigate trip-chaining behaviour by households. The paper reports the results of this analysis and concludes with a summary of the findings and recommendations for further investigations.     

Retrofitted plug-in hybrid vehicles: Results of NYIT drive share program

This paper presents results from a plug-in hybrid vehicle drive share program involving retrofitted hybrid electric vehicles. A potential for high fuel efficiency is indicated, however, the average fuel efficiency was only marginally better than conventional hybrid vehicles. This is due to the majority of vehicle miles traveled occurring on trips outside the “all electric” range and very short trips where fuel consumption is dominated by emissions control strategies. The work also considers the availability of the battery for vehicle to grid services and finds that there are a large number of trips in the afternoon period, typically when electrical demand is at a peak. Vehicle charging activity also tended towards daytime activity, contrary to the oft-assumed off-peak charging pattern.