An activity-episode generation model that captures interactions between household heads: development and empirical analysis

In this paper, we develop an approach for modeling the daily number of non-work, out-of-home activity episodes for household heads that incorporates in its framework both interactions between such members and activity setting (i.e. independent and joint activities). Trivariate ordered probit models are estimated for the heads of three household types – couple, non-worker; couple, one-worker; and couple, two-worker households – using data from a trip diary survey that was conducted in the Greater Toronto Area (GTA) during 1987. Significant interactions between household heads are found. Moreover, the nature of these interactions is shown to vary by household type implying that decision-making structures and, more generally, household dynamics also vary by household type. In terms of predictive ability, the models incorporating interactions are found to predict more accurately than models excluding interactions. The empirical findings emphasize the importance of incorporating interactions between household members in activity-based forecasting models.     

What is the relationship between online activity and driving-licence-holding amongst young adults?

There is growing interest amongst both practitioners and researchers in the correlates of young adults’ driving-licence-acquisition. One aspect of the ongoing scholarly debate is whether taking part in online (i.e. virtual) activities may be associated with young adults feeling less need to drive and hence to acquire a driving licence. This paper addresses this issue by drawing on analysis of two distinct datasets. Both contain rich pseudo-diary instruments in which people indicate detailed characteristics of their unique online-activity profile. This includes both indicators of the types of online activities in which respondents participate, and a separate metric of internet-use intensity. The latter is defined in one dataset as the amount of time/week spent online, and in the other dataset the frequency of their internet use. On the basis of a set of multivariate regression analyses, a positive (i.e. complementary) cross-sectional relationship between young adults’ online activity and licence-holding was found. We find that young adults who use the internet are, net of confounding effects, more likely to hold a driving licence than otherwise identical young adults who do not use the internet. Both datasets show this type of effect, and it is robust across a range of model specifications, including multi-stage estimations to address cross-correlation between indicators of internet usage. In addition to the positive net statistical association, we also report several other noteworthy effects. Of the six effects associated with online-activity types that are directly comparable between the two datasets, we find that the correlation in the parameter estimates across the two datasets is 0.63. This suggests similar types of relationships across the two datasets. Also, in several (but not all) of our analyses we found an inverted ‘U’ shaped ceteris paribus relationship between intensity-of-internet-use and licence-holding. The positive net statistical association between internet use and licence-holding is a different relationship than previously reported in the literature, and therefore further research is needed to reconcile the differences (which are likely due at least in part to different methodological approaches and data resources). Further research is also needed to continue to resolve between the relative saliency of other hypothesised determinants of licence-holding (e.g. economic and socio-demographic explanators, as well as licence-acquisition regimes that vary by time and place).     

Competition and Ownership in Land Passenger Transport: The Sixth International Conference,Cape Town,South Africa,September 1999 - Part 2

This paper presents an overview of some recent developments in and policy issues relating to integrated transport systems in the European Union (EU). Both goods and passenger transport systems are considered in the context of actions recently undertaken and supported by the EU. The paper considers the very general background of these systems at the EU scale and offers insights into some recent successful and promising policy, real-life, and research attainments. In addition, it attempts to identify some directions for future actions in fields such as transport policy, transport technology, transport economics and transport scenarios.     

Examining Residents’ Proximity,Recreational Use,and Perceptions Regarding Proposed Aquaculture Development

Competing interests related to marine resources have the potential to create conflict in the coastal zone. In many parts of the world marine farms exist in close proximity to areas that support recreation and tourism. The purpose of this study was to examine residents’ perceptions of proposed marine farm development related to their proximity to, and recreational use of, a coastal area in New Zealand. Residents from two areas were surveyed about their recreational use of the region and about perceptions related to marine farm development. Results indicated that those living closest to proposed marine farms used the area more often and in different ways, were most sensitive to marine farm development, and were less positive in their evaluations of marine farms, despite agreeing that marine farms can have positive economic consequences for nearby communities. Implications for using stakeholder input for the planning and management of marine farms are discussed.     

Vehicle automation and freeway ‘pipeline’ capacity in the context of legal standards of care

Transportation - The study evaluates, in the context of freeway segments, the interaction between automated cars’ kinematic capabilities and the standard legal requirement for the operator of...     

Effect of Frame Compliance on the Lateral Dynamics of Motorcycles

The lateral dynamics of an uncontrolled motorcycle, running on a straight, level road surface, is investigated in this paper. The structural compliances in the front and the rear frames of the motorcycle are taken into account by introducing additional degrees of freedom in the analysis. The kinematics of the tires is represented by linear differential equations which are based on the taut-string model of pneumatic tires. The linear differential equations of motion are solved to yield the eigensolutions of the system. Numerical results, obtained for parameters corresponding to a Honda CB750 motorcycle, are presented and discussed.     

Making mode detection transferable: extracting activity and travel episodes from GPS data using the multinomial logit model and Python

The increasing popularity of global positioning systems (GPSs) has prompted transportation researchers to develop methods that can automatically extract and classify episodes from GPS data. This paper presents a transferable and efficient method of extracting and classifying activity episodes from GPS data, without additional information. The proposed method, developed using Python®, introduces the use of the multinomial logit (MNL) model in classifying extracted episodes into different types: stop, car, walk, bus, and other (travel) episodes. The proposed method is demonstrated using a GPS dataset from the Space-Time Activity Research project in Halifax, Canada. The GPS data consisted of 5127 person-days (about 47 million points). With input requirements directly derived from GPS data and the efficiency provided by the MNL model, the proposed method looks promising as a transferable and efficient method of extracting activity and travel episodes from GPS data.     

Dynamic pricing of free-floating carsharing networks with sensitivity to travellers’ attitudes towards risk

Transportation - Free-floating carsharing (FFCS) systems are characterised by volatile fleet distribution as well as customers’ heterogeneous price sensitivity and spatiotemporal flexibility....     

Visual air navigation siting

The principle of a Precision Approach Path Indicator (PAPI) System is to provide the pilot with an on‐slope signal and guide the aircraft down to the runway safely. Threshold Crossing Height (TCH) related to PAPI siting ensures that aircraft have a certain landing gear clearance over the runway threshold. Therefore, it is an important parameter in PAPI siting. In this paper, the factors related to PAPI siting are addressed and the determinations of the TCHs for PAPI and ILS (Instrument Landing System) are discussed. Most importantly, two approaches to calculate the eye‐to‐wheel height are proposed and a procedure to quickly check a PAPI siting also developed. The results show that the angle on which a TCH is based affects the NAVAIDS siting, and that any calculation of TCH should be based on the lowest angle in order to maintain the acceptable minimum wheel‐to‐threshold (WTH) height of 10 feet.     

The analysis of entropy models with equality and inequality constraints

Entropy models are emerging as valuable tools in the study of various social problems of spatial interaction. With the development of the modelling has come diversity. Increased flexibility in the model can be obtained by allowing certain constraints to be relaxed from equality to inequality. To provide a better understanding of these entropy models they are analysed by geometric programming. Dual mathematical programs and algorithms are obtained.