Will automated vehicles negatively impact traffic flow?

With low-level vehicle automation already available, there is a necessity to estimate its effects on traffic flow, especially if these could be negative. A long gradual transition will occur from manual driving to automated driving, in which many yet unknown traffic flow dynamics will be present. These effects have the potential to increasingly aid or cripple current road networks. In this contribution, we investigate these effects using an empirically calibrated and validated simulation experiment, backed up with findings from literature. We found that low-level automated vehicles in mixed traffic will initially have a small negative effect on traffic flow and road capacities. The experiment further showed that any improvement in traffic flow will only be seen at penetration rates above 70%. Also, the capacity drop appeared to be slightly higher with the presence of low-level automated vehicles. The experiment further investigated the effect of bottleneck severity and truck shares on traffic flow. Improvements to current traffic models are recommended and should include a greater detail and understanding of driver-vehicle interaction, both in conventional and in mixed traffic flow. Further research into behavioural shifts in driving is also recommended due to limited data and knowledge of these dynamics. Document type: Articl

Macroscopic analysis and modelling of multi-class, flexible-lane traffic

An excessive demand of vehicles to a motorway bottleneck leads to traffic jams. Motorbikes are narrow and can drive next to each other in a lane, or in-between lanes in low speeds. This paper analyses the resulting traffic characteristics and presents numerical scheme for a macroscopic traffic flow model for these two classes. The behavior included is as follows. If there are two motorbikes behind each other, they can travel next to each other in one lane, occupying the space of one car. Also, at low speeds of car traffic, they can go in between the main lanes, creating a so-called filtering lane. The paper numerically derives functions of class-specific speeds as function of the density of both classes, incorporating flexible lane usage dependent on the speed. The roadway capacity as function of the motorbike fraction is derived, which interesting can be in different types of phases (with motorbikes at higher speeds or not). We also present a numerical scheme to analyse the dynamics of this multi-class system. We apply the model to an example case, revealing the properties of the traffic stream , queue dynamics and class specific travel times. The model can help in showing the relative advantage in travel time of switching to a motorbike

Impact of radio channel characteristics on the longitudinal behaviour of truck platoons in critical car-following situations

Truck platooning is an application of cooperative adaptive cruise control (CACC) which relies on vehicle-to-vehicle communications facilitated by vehicle ad-hoc networks. Communication uncertainties can affect the performance of a CACC controller. Previous research has not considered the full spectrum of possible car-following scenarios needed to understand how the longitudinal behaviour of truck platoons would be affected by changes in the communication network. In this paper, we investigate the impact of radio channel parameters on the string stability and collision avoidance capabilities of a CACC controller governing the longitudinal behaviour of truck platoons in a majority of critical car-following situations. We develop and use a novel, sophisticated and open-source VANET simulator OTS-Artery, which brings microscopic traffic simulation, network simulation, and psychological concepts in a single environment, for our investigations. Our results indicate that string stability and safety of truck platoons are mostly affected in car-following situations where truck platoons accelerate from the standstill to the maximum speed and decelerate from the maximum speed down to the standstill. The findings suggest that string stability can be improved by increasing transmission power and lowering receiver sensitivity. However, the safety of truck platoons seems to be sensitive to the choice of the path loos model

Comparison of the haptic and visual deviations in a parallelity task

Deviations in both haptic and visual spatial experiments are thought to be caused by a biasing influence of an egocentric reference frame. The strength of this influence is strongly participant-dependent. By using a parallelity test, it is studied whether this strength is modality-independent. In both haptic and visual conditions, large, systematic and participant-dependent deviations were found. However, although the correlation between the haptic and visual deviations was significant, the explained variance due to a common factor was only 20%. Therefore, the degree to which a participant is “egocentric” depends on modality and possibly even more generally, on experimental condition

The party road to representation: Unequal responsiveness in party platforms

This paper explores a major road to substantive representation in democracies, by clarifying whether demands of rich and poor citizens are taken up in the electoral platforms of political parties. Doing so constitutes a substantial broadening and deepening of our understanding of substantive representation – broadening the countries, issue-areas and years that form the empirical basis for judging whether democracies manifest unequal representation; and deepening the process of representation by clarifying a key pathway connecting societal demands to policy outcomes. The paper hypothesises that party systems in general will respond more strongly to wealthy than to poor segments of a polity. It also hypothesises that left parties will more faithfully represent poorer and less significantly represent richer citizens than do right parties. We find substantial support for these expectations in a new dataset that combines multi-country, multi-issue-area, multi-wave survey data with data on party platforms for 39 democracies

Assessment of Implementing Carbon Capture Technologies in Fossil Fuel Power Plants on Regional European Water Stress Index Levels

Equipping power plants with carbon capture technologies increases the (cooling) water demand of these plants. This study explores the potential impact of such increase in water demand on the regional water scarcity in Europe. A database with key characteristics of 458 of the largest European power plants is developed and the water use of these power plants is estimated. The water use of the power plants are spatially linked to current water stress index levels. Several prospective scenarios are developed accounting for variations in the future configuration of Europe's electricity generation and different penetration rates of carbon capture technology. Regional water stress index levels are calculated to compare the potential impact of applying carbon capture technologies on the water stress. Preliminary results indicate that the increase of water use due to carbon capture technology is partly expected to be compensated by the deployment of more efficient energy conversion methods which require less cooling water. As such, no significant increase in water stress is expected in the short term (2030), as the carbon capture penetration level in European power plants is expected to be quite low. However, on the long term (2050), large scale instalment of carbon capture technologies in power plants might significantly increase the water stress throughout Europe.ISSN:1876-610

Real but unequal representation in welfare state reform

Scholars have long debated whether welfare policymaking in industrialized democracies is responsive to citizen preferences, and whether such policymaking is more responsive to rich than to poor citizens. These debates have been hampered, however, by difficulties in matching data on attitudes towards particular policies to data on changes in actual policy generosity. This paper uses better, more targeted measures of policy change that allow more valid exploration of responsiveness for a significant range of democracies. It does so by linking multi-country and multi-wave survey data on attitudes towards health, pension and unemployment policies, to data on actual policy generosity, not just spending, in these domains. This reveals that attitudes strongly correlate with subsequent changes in welfare generosity in the three policy areas, and that such responsiveness is much stronger for richer than for poorer citizens. Representation is likely real but also vastly unequal in the welfare politics of industrialized democracies

Impact of Fuel Selection on Techno-environmental Performance of Post-combustion Calcium Looping Process Applied to a Cement Plant

Calcium looping CO2 capture is a promising technology to reduce CO2 emissions from cement production. Coal is generally considered the fuel used to drive the calcium looping process as coal is already used as feedstock for cement production. This study assesses the impact of different fuels (coal, natural gas and woody biomass) on the technological and environmental performance of post-combustion calcium looping at a cement plant in North-western Europe. Process modelling is used to determine the impact of the different fuels on the mass and energy balance of the process. Life cycle assessment is carried out to evaluate the environmental performance of the different systems. Results indicate that firing natural gas or biomass instead of coal in an add-on calcium looping process can improve the efficiency of the process, as it decreases the fuel, limestone and electricity consumption. Consequently, while coal fired calcium looping can reduce life cycle climate change potential by 92%, the use of natural gas or biomass can make the process carbon neutral (reduction of 100%) or negative (-169%), respectively. Further research is required to complete the environmental perspective of using alternative fuels, but these results already illustrate a potential low-hanging fruit to improve the environmental performance of post combustion calcium looping in the cement industry

Impact of Fuel Selection on Techno-environmental Performance of Post-combustion Calcium Looping Process Applied to a Cement Plant

Calcium looping CO2 capture is a promising technology to reduce CO2 emissions from cement production. Coal is generally considered the fuel used to drive the calcium looping process as coal is already used as feedstock for cement production. This study assesses the impact of different fuels (coal, natural gas and woody biomass) on the technological and environmental performance of post-combustion calcium looping at a cement plant in North-western Europe. Process modelling is used to determine the impact of the different fuels on the mass and energy balance of the process. Life cycle assessment is carried out to evaluate the environmental performance of the different systems. Results indicate that firing natural gas or biomass instead of coal in an add-on calcium looping process can improve the efficiency of the process, as it decreases the fuel, limestone and electricity consumption. Consequently, while coal fired calcium looping can reduce life cycle climate change potential by 92%, the use of natural gas or biomass can make the process carbon neutral (reduction of 100%) or negative (-169%), respectively. Further research is required to complete the environmental perspective of using alternative fuels, but these results already illustrate a potential low-hanging fruit to improve the environmental performance of post combustion calcium looping in the cement industry