Modeling the Impact of Vehicle Platooning on Highway Congestion

Vehicle platooning is a promising technology that can lead to significant fuel savings and emission reduction. However, the macroscopic impact of vehicle platoons on highway traffic is not yet well understood. In this article, we propose a new fluid queuing model to study the macroscopic interaction between randomly arriving vehicle platoons and the background traffic at highway bottlenecks. This model, viewed as a stochastic switched system, is analyzed for two practically relevant priority rules: proportional (or mixed) and segmented priority. We provide intuitive stability conditions, and obtain bounds on the long-run average length and variance of queues for both priority rules. We use these results to study how platoon-induced congestion varies with the fraction of platooned vehicles, and their characteristics such as intra-platoon spacing and arrival rate. Our analysis reveals a basic tradeoff between congestion induced by the randomness of platoon arrivals, and efficiency gain due to a tighter intra-platoon spacing. This naturally leads to conditions under which the proportional priority is preferred over segmented priority. Somewhat surprisingly, our analytical results are in agreement with the simulation results based on a more sophisticated two-class cell transmission model.National Science Foundation (U.S.) (CAREER Award CNS-1453126)National Science Foundation (U.S.) (CNS-1239054)Singapore. National Research FoundationHorizon 2020 Framework Programme (European Commission) (Marie Sklodowska-Curie Grant 674875)VINNOVA (Contract 2014- 06200)Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Foundation for Strategic Researc

Analysis and Design of Vehicle Platooning Operations on Mixed-Traffic Highways

Platooning of connected and autonomous vehicles (CAVs) has a significant potential for throughput improvement. However, the interaction between CAVs and non-CAVs may limit the practically attainable improvement due to platooning. To better understand and address this limitation, we introduce a new fluid model of mixed-autonomy traffic flow and use this model to analyze and design platoon coordination strategies. We propose tandem-link fluid model that considers randomly arriving platoons sharing highway capacity with non-CAVs. We derive verifiable conditions for stability of the fluid model by analyzing an underlying M/D/1 queuing process and establishing a Foster-Lyapunov drift condition for the fluid model. These stability conditions enable a quantitative analysis of highway throughput under various scenarios. The model is useful for designing platoon coordination strategies that maximize throughput and minimize delay. Such coordination strategies are provably optimal in the fluid model and are practically relevant. We also validate our results using standard macroscopic (cell transmission model, CTM) and microscopic (Simulation for Urban Mobility, SUMO) simulation models

Modeling the impact of on-line navigation devices in traffic flows

International audienceWe consider a macroscopic multi-population traffic flow model on networks accounting for the presence of drivers (or autonomous vehicles) using navigation devices to minimize their instantaneous travel cost to destination. The strategic choices of each population differ in the degree of information about the system: while part of the agents knows only the structure of the network and minimizes the traveled distance, others are informed of the current traffic distribution, and can minimize their travel time avoiding the most congested areas. In particular, the different route choices are computed solving eikonal equations on the road network and they are implemented at road junctions. The impact on traffic flow efficiency is illustrated by numerical experiments. We show that, even if the use of routing devices contributes to alleviate congestion on the whole network, it also results in increased traffic on secondary roads. Moreover, the generalized use of real-time information can even deteriorate the efficiency of the network

A Review of Big Data in Road Freight Transport Modeling: Gaps and Potentials

Road transport accounted for 20% of global total greenhouse gas emissions in 2020, of which 30% come from road freight transport (RFT). Modeling the modern challenges in RFT requires the integration of different freight modeling improvements in, e.g., traffic, demand, and energy modeling. Recent developments in \u27Big Data\u27 (i.e., vast quantities of structured and unstructured data) can provide useful information such as individual behaviors and activities in addition to aggregated patterns using conventional datasets. This paper summarizes the state of the art in analyzing Big Data sources concerning RFT by identifying key challenges and the current knowledge gaps. Various challenges, including organizational, privacy, technical expertise, and legal challenges, hinder the access and utilization of Big Data for RFT applications. We note that the environment for sharing data is still in its infancy. Improving access and use of Big Data will require political support to ensure all involved parties that their data will be safe and contribute positively toward a common goal, such as a more sustainable economy. We identify promising areas for future opportunities and research, including data collection and preparation, data analytics and utilization, and applications to support decision-making

АКАРИЦИДИ ТА ЇХ ЗАСТОСУВАННЯ (ЧАСТИНА 2)

SUMMARY. Tick-borne infections are becoming more common. They pose a problem not only in human medicine, but also in veterinary medicine and agriculture. At the same time, the fight against ticks, which serve as a reservoir and carrier of pathogens of many human and animal diseases, is far from being resolved. The purpose of this literature review was to analyze modern achievements in the creation and use of acaricidal drugs, which has not yet been sufficiently covered in Ukraine. The article provides classifications of the acaricidal drugs used, according to their effect on ticks at different stages of development, chemical composition, mechanism of harmful action, and other criteria. The characteristics of the main acaricides belonging to the relevant chemical groups and their effectiveness against ticks of certain genera are given. The possible harmful effects of these compounds on humans, animals and the environment are considered. The global experience of using certain drugs in the medical and veterinary fields, a number of practical recommendations aimed at achieving the maximum acaricidal effect are summarized. The problem of tick resistance to acaricides, its causes and methods of prevention and overcoming are discussed in detail. Alternative methods of tick control are briefly considered. On the basis of dictates from the literature, practical advice on the rational use of modern acaricides was compiled.Кліщові інфекції набувають все більшого поширення. Вони складають проблему не тільки в медицині людей, але й ветеринарії та сільському господарстві. Водночас боротьба з кліщами, які служать резервуаром і переносником збудників багатьох хвороб людей і тварин, далека від вирішення. Метою цього огляду літератури було проаналізувати сучасні досягнення у створенні та використанні акарицидних препаратів, що досі в Україні не знайшло достатнього висвітлення. У статті наведено класифікації акарицидних препаратів, які використовуються, за дією на кліщів на різних стадіях розвитку, хімічним складом, механізмом згубної дії та іншими критеріями. Подана характеристика основних акарицидів, що належать до відповідних хімічних груп, та їх дієвість щодо кліщів певних родів. Розглянуто можливий шкідливий вплив цих сполук на людину, тварин і довкілля. Узагальнено світовий досвід використання окремих препаратів у медичній та ветеринарній галузях, низку практичних рекомендацій, спрямованих на досягнення максимального акарицидного ефекту. Детально обговорено проблему резистентності кліщів до акарицидів, її причини і способи попередження та подолання. Стисло розглянуто альтернативні методи боротьби з кліщами. На основі даних літератури складено практичні поради щодо раціонального використання сучасних акарицидних засобів

A macroscopic traffic flow model with finite buffers on networks: Well-posedness by means of Hamilton-Jacobi equations

International audienceWe introduce a model dealing with conservation laws on networks and coupled boundary conditions at the junctions. In particular, we introduce buffers of fixed arbitrary size and time dependent split ratios at the junctions , which represent how traffic is routed through the network, while guaranteeing spill-back phenomena at nodes. Having defined the dynamics at the level of conservation laws, we lift it up to the Hamilton-Jacobi (H-J) formulation and write boundary datum of incoming and outgoing junctions as functions of the queue sizes and vice-versa. The Hamilton-Jacobi formulation provides the necessary regularity estimates to derive a fixed-point problem in a proper Banach space setting, which is used to prove well-posedness of the model. Finally, we detail how to apply our framework to a non-trivial road network, with several intersections and finite-length links

Integration of Information Patterns in the Modeling and Design of Mobility Management Services

24 pages, 11 FiguresOver the last decade, the rise of the mobile internet and the usage of mobile devices has enabled ubiquitous traffic information. With the increased adoption of specific smartphone applications, the number of users of routing applications has become large enough to disrupt traffic flow patterns in a significant manner. Similarly, but at a slightly slower pace, novel services for freight transportation and city logistics improve the efficiency of goods transportation and change the use of road infrastructure. The present article provides a general four-layer framework for modeling these new trends. The main motivation behind the development is to provide a unifying formal system description that can at the same time encompass system physics (flow and motion of vehicles) as well as coordination strategies under various information and cooperation structures. To showcase the framework, we apply it to the specific challenge of modeling and analyzing the integration of routing applications in today's transportation systems. In this framework, at the lowest layer (flow dynamics) we distinguish app users from non-app users. A distributed parameter model based on a non-local partial differential equation is introduced and analyzed. The second layer incorporates connected services (e.g., routing) and other applications used to optimize the local performance of the system. As inputs to those applications, we propose a third layer introducing the incentive design and global objectives, which are typically varying over the day depending on road and weather conditions, external events etc. The high-level planning is handled on the fourth layer taking social long-term objectives into account