The future of road transport

A perfect storm of new technologies and new business models is transforming not only our vehicles, but everything about how we get around, and how we live our lives. The JRC report “The future of road transport - Implications of automated, connected, low-carbon and shared mobility” looks at some main enablers of the transformation of road transport, such as data governance, infrastructures, communication technologies and cybersecurity, and legislation. It discusses the potential impacts on the economy, employment and skills, energy use and emissions, the sustainability of raw materials, democracy, privacy and social fairness, as well as on the urban context. It shows how the massive changes on the horizon represent an opportunity to move towards a transport system that is more efficient, safer, less polluting and more accessible to larger parts of society than the current one centred on car ownership. However, new transport technologies, on their own, won't spontaneously make our lives better without upgrading our transport systems and policies to the 21st century. The improvement of governance and the development of innovative mobility solutions will be crucial to ensure that the future of transport is cleaner and more equitable than its car-centred present.JRC.C.4-Sustainable Transpor

Empirical study on the properties of adaptive cruise control systems and their impact on traffic flow and string stability

Adaptive cruise control (ACC) systems are standard equipment in many commercially available vehicles. They are considered the first step of automation, and their market penetration rate is expected to rise, along with the interest of researchers worldwide to assess their impact in relation to traffic flow and stability. These properties are currently discussed mainly through microsimulation studies and empirical observations, with the first being the most common. Experimental observations can draw safer conclusions about the behavior of such systems, but the literature is limited. In this work, an experimental campaign with five vehicles equipped with ACC was conducted at the proving ground of AstaZero in Sweden to improve understanding on the properties of ACC systems and their functionality under real driving conditions. The main parameters under investigation are the response time of controllers, the available time headway settings, and the stability of the car-platoon. The results show that the response time range for the controllers is between 1.7 and 2.5 s, significantly longer than the values reported in the literature. The range of the time headway settings was found to be quite broad. Finally, a dataset of perturbations on a variety of equilibrium speeds of the car-platoon and of variable magnitudes was created. Results clearly highlight the instability of the car-platoon. Instability is also displayed even for slight perturbations derived by variability in the road gradient. Numerical differentiation on the altitude shows a negative correlation with the speed trajectory of the leading vehicle

Empirical study on the properties of adaptive cruise control systems and their impact on traffic flow and string stability

Adaptive Cruise Control (ACC) systems appear as standard equipment in many commercially available vehicles. There are considered the first step of automation, and their market penetration rate is expected to rise, along with the interest of researchers worldwide to assess their impact in terms of traffic flow and stability. These properties are currently discussed mainly through microsimulation studies and empirical observations, with the first being the most common. Experimental observations can draw safer conclusions about the behavior of such systems but there are only a few in the literature. In this work, an experimental campaign with 5 vehicles equipped with ACC has been organized in the proving ground of AstaZero in Sweden to raise understanding on the properties of the ACC systems and their functionality under real driving conditions. The main parameters under investigation are the response time of controllers, the available time headway settings and the stability of the car-platoon. The results show that the response time range for the controllers is between 1.7s and 2.5s, significantly higher than the values reported in the literature. The time headway with the minimum setting and normal driving conditions is a bit over 1s for all the vehicles, while with the maximum setting it can reach 3.5s. Finally, imposed perturbations of variable magnitudes lead to instability for the car-platoon. Furthermore, instability appears even for slight perturbations derived by the variability in the road slope. Numerical differentiation on the altitude shows a negative correlation with the speed trajectory of the leading vehicle.JRC.C.4-Sustainable Transpor

On the compensation mechanism of amorphous silicon films: study of stability

We investigated a-Si:H compensated materials deposited over a wide range of gas dopant concentrations, from 0.125 ppm up to 103 ppm. We achieved compensation for different ratio in the gas phase of diborane and phosphine, depending on their concentration. As a relevant result, we found that at constant boron concentration compensation occurs by using two different values of phosphine flow. This behavior can be described by a change of formation mechanism involving active dopants, defects and boron-phosphorus complex, that occurs in a different way depending on the dopant concentrations. The two compensation regimes are evidenced also by a different behavior under light soaking. Furthermore we found that photocurrent evolution under illumination is determined by two concurrent mechanisms: activation of dopant species and increase of defect densit