Cycle commuting in Belgium: Spatial determinants and ‘re-cycling’ strategies

This paper attempts to explain the spatial variation of the use of a bicycle for commuting to work at the level of the 589 municipalities in Belgium. Regression techniques were used and special attention was paid to autocorrelation, heterogeneity and multicollinearity. Spatial lag models were used to correct for the presence of spatial dependence and a disaggregated modelling strategy was adopted for the northern and southern parts of the country. The results show that much of the inter-municipality variation in bicycle use is related to environmental aspects such as the relief, traffic volumes and cycling accidents. Town size, distance travelled and demographic aspects also have some effect. In addition, there are regional differences in the effects of the structural covariates on bicycle use: the impact of variables such as traffic volume and cycling accidents differs substantially between the north and the south of the country. This paper also suggests that high rates of bicycle use in one municipality stimulate cycling in neighbouring municipalities, and hence that a mass effect can be initiated, i.e. more cycle commuting encourages even more commuters in the area to cycle. These findings provide some recommendations for decision-makers wishing to promote a shift from car to bicycle use.     

Climate Change and Tourist Comfort on Europe's Beaches in Summer: A Reassessment

Major impacts of climate change have been projected for tourism in Europe. Typically, these projections took general tourism activities such as sight-seeing and their climate requirements as their point of reference. The purpose of this study is to reassess the impact of climate change, by looking specifically at beach tourism in summer, a crucial market segment in Europe and more specifically in the Mediterranean. As beach tourism requires relatively high temperatures, relatively modest shifts in attractiveness are found. With respect to climate, the Mediterranean is likely to remain Europe's prime region for summer-time beach tourism for at least the next 50 years. Coastal managers in Mediterranean destinations are advised to focus some of their attention on other climate change impacts such as sea-level rise or water availability, and include environmental quality and diversification of activities in their deliberations. In non-Mediterranean regions, a promising strategy may be to focus on short- and medium-distance visitors who can take advantage of the new opportunities for beach tourism, and to explore the merits of seasonal climate forecasting.     

Exploring temporal fluctuations of daily cycling demand on Dutch cycle paths: the influence of weather on cycling

In the pursuit of sustainable mobility policy makers are giving more attention to cycling. The potential of cycling is shown in countries like the Netherlands, where cycling covers 25 % of all person trips. However, the effect of policy interventions on cycling demand is difficult to measure, not least caused by difficulties to control for changing context variables like weather conditions. According to several authors weather has a strong influence on cycling demand, but quantitative studies about the relationship are scarce. We therefore further explored this relationship, with the aim of contributing to the development of a generic demand model with which trend and coincidence in bicycle flows might be unraveled. The study is based on time-series between 1987 and 2003 of daily bicycle flows, collected on 16 cycle paths near two cities in the Netherlands. The regression analyses show that, not surprisingly, recreational demand is much more sensitive to weather than utilitarian demand. Most daily fluctuations (80 %) are described by weather conditions, and no less than 70 % of the remaining variation is locally constrained. The regression can therefore mainly be improved by incorporating path specific, as yet unknown, variables. We used the regression results to calculate weather-inclusive bicycle flow predictions and found indications of a downward trend in recreational demand. This trend has been off-set in the observed flows by more favorable weather conditions over the years considered.     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

IdleStop and Go: a way to improve fuel economy

This paper proposes a mechanical solution to save fuel by shutting down an internal combustion engine whenever it is unnecessary for propulsion, e.g., when a vehicle is waiting for traffic lights. The engine and vehicle are restarted using the energy that is stored in a flywheel. Two additional clutches are needed to enable appropriate power flow from the flywheel to the engine and vehicle. This complicates the powertrain dynamics in that the number of degrees of freedom changes due to clutch operations. Therefore, a hybrid control strategy, which is treated as a top-level controller, is introduced to deal with this finite-state mechanical system. At the lower level, the engine and clutches are controlled in a coordinated manner such that the vehicle is launched according to the driver's demands. Using a comprehensive powertrain simulation package, the proposed controller is evaluated numerically.     

E-bikes among older adults: benefits,disadvantages, usage and crash characteristics

Transportation - The promotion of sustainable and healthy mobility among older adults (≥?65 years) is an important challenge. E-bikes may be part of the solution, but research...     

形位精度统计分析中常值系统性误差的确定

本文分析了常值系统性误差的传统确定方法不适用于形位精度统计分析的原因,并提出了形位精度统计分析中常值系统性误差的确定方法。