In recent years, the use of remote operation has been proposed as a bridge towards driverless mobility by providing human assistance remotely when an automated driving system finds a situation that is ambiguous and requires input from a remote operator. The remote operation of road vehicles has also been proposed as a way to enable drivers to operate vehicles from safer and more comfortable locations. While commercial solutions for remote operation exist, remaining challenges are being tackled by the research community, who is continuously testing and validating the feasibility of deploying remote operation of road vehicles on public roads. These tests range from the technological scope to social aspects such as acceptability and usability that affect human performance. This survey presents a compilation of works that approach the remote operation of road vehicles. We start by describing the basic architecture of remote operation systems and classify their modes of operation depending on the level of human intervention. We use this classification to organize and present recent and relevant work on the field from industry and academia. Finally, we identify the challenges in the deployment of remote operation systems in the technological, regulatory, and commercial scopes.

Sammanfattningsvis definierar vi i denna guide ’smarta gator’ kort sagt som mångfunktionella, levande, långsamma, ekologiska och flexibla gator. Det övergripande målet med denna guide är följaktligen ”Smarta gator för en hållbar stadsutveckling”.

Automated and connected traffic systems with cooperative functionality need effective testing. One way to enable such testing is to represent the current traffic environment by co-simulating different simulators using a communication layer between the simulators for cooperative functionality. With this approach, this paper presents a platform with its included simulators (vehicle, pedestrian, and traffic simulators), the used run-time infrastructure (RTI) for co-simulation, and the connection to the Unreal Engine based visual system for the simulators. The architecture was tested with two vehicle simulators (one autonomous bus and a truck), one pedestrian simulator, and one traffic simulator connected using a cloud-based service for the RTI.

In this work we propose a new cooperation strategy between connected autonomous vehicles in on-ramps merging scenarios and we implement the cut-in risk indicator (CRI) to investigate the safety effect of the proposed strategy. The new cooperation strategy considers a pair of vehicles approaching an on-ramp. The strategy then makes decisions on the target speeds/accelerations of both vehicles, possible lane changing, and a dynamic decision-making approach in order to reduce the risk during the cut-in manoeuvre. In this work, the CRI was first used to assess the risk during the merging manoeuvre. For this purpose, scenarios with penetration rates of autonomous vehicles from 20% to 100%, with step of 10%, both connected and non-connected autonomous vehicles were evaluated. As a result, on average a 35% reduction of the cut-in risk manoeuvres in connected autonomous vehicles compared to non-connected autonomous vehicles is obtained. It is shown through the analysis of probability density functions characterising the CRI distribution that the reduction is not homogeneous across all indicator values, but depends on the penetration rate and the severity of the manoeuvre.

This report presents experimental setups and findings from the REDO project, which had been conducted between December 2019 and February 2023. Five main topics are covered in this report: 1) Effects of latency and field-of-view on driving performance; 2) Remote driving feedback and control; 3) Connectivity and mobile network support for remote driving; 4) Video transmission for remote driving; and 5) Laws and regulations concerning remote driving. Contents of this report dives into technical details and findings within each topic. Nevertheless, this report does not intend to repeat all detail and results published in scientific publications, and thus this report should be seen as complementary material to the published results.

Purpose: This paper aims to explore whether drivers would adapt their behavior when they drive among automated vehicles (AVs) compared to driving among manually driven vehicles (MVs).Understanding behavioral adaptation of drivers when they encounter AVs is crucial for assessing impacts of AVs in mixed-traffic situations. Here, mixed-traffic situations refer to situations where AVs share the roads with existing nonautomated vehicles such as conventional MVs.

Design/methodology/approach: A driving simulator study is designed to explore whether such behavioral adaptations exist. Two different driving scenarios were explored on a three-lane highway: driving on the main highway and merging from an on-ramp. For this study, 18 research participants were recruited.

Findings: Behavioral adaptation can be observed in terms of car-following speed, car-following time gap, number of lane change and overall driving speed. The adaptations are dependent on the driving scenario and whether the surrounding traffic was AVs or MVs. Although significant differences in behavior were found in more than 90% of the research participants, they adapted their behavior differently, and thus, magnitude of the behavioral adaptation remains unclear.

Originality/value: The observed behavioral adaptations in this paper were dependent on the driving scenario rather than the time gap between surrounding vehicles. This finding differs from previous studies, which have shown that drivers tend to adapt their behaviors with respect to the surrounding vehicles. Furthermore, the surrounding vehicles in this study are more “free flow'” compared to previous studies with a fixed formation such as platoons. Nevertheless, long-term observations are required to further support this claim.

It is currently unknown how automated vehicle platoons will be perceived by other road users in their vicinity. This study explores how drivers of manually operated passenger cars interact with automated passenger car platoons while merging onto a highway, and how different inter-vehicular gaps between the platooning vehicles affect their experience and safety. The study was conducted in a driving simulator and involved 16 drivers of manually operated cars. Our results show that the drivers found the interactions mentally demanding, unsafe, and uncomfortable. They commonly expected that the platoon would adapt its behavior to accommodate a smooth merge. They also expressed a need for additional information about the platoon to easier anticipate its behavior and avoid cutting-in. This was, however, affected by the gap size; larger gaps (30 and 42.5 m) yielded better experience, more frequent cut-ins, and less crashes than the shorter gaps (15 and 22.5 m). A conclusion is that a short gap as well as external human–machine interfaces (eHMI) might be used to communicate the platoon's intent to “stay together”, which in turn might prevent drivers from cutting-in. On the contrary, if the goal is to facilitate frequent, safe, and pleasant cut-ins, gaps larger than 22.5 m may be suitable. To thoroughly inform such design trade-offs, we urge for more research on this topic. © 2021 The Author(s)

Cut-in situations occurs when a vehicle intentionally changes lane and ends up in front of another vehicle or in-between two vehicles. In such situations, having a method to indicate the collision risk prior to making the cut-in maneuver could potentially reduce the number of sideswipe and rear end collisions caused by the cut-in maneuvers. This paper propose a new risk indicator, namely cut-in risk indicator (CRI), as a way to indicate and potentially foresee collision risks in cut-in situations. As an example use case, we applied CRI on data from a driving simulation experiment involving a manually driven vehicle and an automated platoon in a highway merging situation. We then compared the results with time-to-collision (TTC), and suggest that CRI could correctly indicate collision risks in a more effective way. CRI can be computed on all vehicles involved in the cut-in situations, not only for the vehicle that is cutting in. Making it possible for other vehicles to estimate the collision risk, for example if a cut-in from another vehicle occurs, the surrounding vehicles could be warned and have the possibility to react in order to potentially avoid or mitigate accidents.

Platooning refers to a group of vehicles that--enabled by wireless vehicle-to-vehicle (V2V) communication and vehicle automation--drives with short inter-vehicular distances. Before its deployment on public roads, several challenging traffic situations need to be handled. Among the challenges are cut-in situations, where a conventional vehicle--a vehicle that has no automation or V2V communication--changes lane and ends up between vehicles in a platoon. This paper presents results from a simulation study of a scenario, where a conventional vehicle, approaching from an on-ramp, merges into a platoon of five cars on a highway. We created the scenario with four platooning gaps: 15, 22.5, 30, and 42.5 meters. During the study, the conventional vehicle was driven by 37 test persons, who experienced all the platooning gaps using a driving simulator. The participants' opinions towards safety, comfort, and ease of driving between the platoon in each gap setting were also collected through a questionnaire. The results suggest that a 15-meter gap prevents most participants from cutting in, while causing potentially dangerous maneuvers and collisions when cut-in occurs. A platooning gap of at least 30 meters yield positive opinions from the participants, and facilitating more smooth cut-in maneuvers while less collisions were observed.

This thesis aims to explore, analyze, and develop knowledge that leads to an understanding of identifying the key actors and their symbiotic relationships and dependencies in transforming the energy and transportation system from fossil-based to renewable and fossil fuel-powered vehicles to electric. 

The research was explorative and categorized into two studies. The Study – I focuses on the technological development that leads toward transforming from the old fossil-based analog electricity generation and distribution system to the new digitalized renewable system. This study further explores the impact of these disruptive technologies on the market and society, and the challenges hindering the implementation and adoption of the new energy system. Study – II focuses on developing new knowledge and understanding by integrating technological, political, societal, and economic aspects into one model and named it a 'multidimensional readiness index model.' This model can serve as an analytical tool and provide a broader perspective for exploring, analyzing, evaluating, and determining the countries' positions in transforming the transformation system. The model has been applied to eight countries, two from Asia (China and India) and Australia and five from Europe (Germany, Norway, Sweden, Slovenia, and the UK). The kappa synthesizes the exploration of the papers. Additionally, the system approach is applied to explore and understand the symbiotic relationship in the new ecosystem among the key actors and stakeholders and their significant role in transforming the transportation system from fossil-based to electric. 

The main conclusion is that the countries with a higher symbiotic relationship among the key actors achieved a higher level of readiness in transforming the transportation system. In contrast, other countries with a low symbiotic relationship among the key actors are slowly catching up or even far behind in transforming the transportation system towards electrification.

To investigate the reasons for shifting from the old to the new energy system, the impact of this disruptive technology on energy providing firms, the demand for the new business model and the approach of the new business model in terms of creating and capturing values published peer-reviewed articles, and international energy agency reports have been reviewed. This paper encourages energy providing firms to redesign business models for commercializing new energy distribution system and to offer new services to the energy consumers for their future survival in the new trends of the energy market. These services include integrating with renewable energy sources, electric vehicle services, and demand response services to create more value for the consumers and in return gains more profit for each actor.

The services provided through integration of renewable energy with smart grid and the electric vehicle will empower consumers involvement in the electricity system which will give them more control over electricity. CO₂ production will be reduced, helping to create a clean environment and will enable operators to improve grid security and network stability. Finally, demand response services will provide multiple electricity package options to the consumers in which they can select an appropriate package according to their need which will give them more control over their electricity bill. System operators can optimize their grid operations to provide better power quality, and service providers can increase their income by offering additional services.

The peer-reviewed articles and published government reports have been reviewed, based on the analysis of technical characteristics of power generation systems, eco-friendly sources of power generations, cost reduction, functionality and design of traditional grid versus smart grid. Furthermore, the innovative technologies that enable the grid to integrate with decentralized power generation system efficiently have been considered. This paper claims that in this modern era, it is arduous for traditional grid to fulfill the rising demand of electricity, along with sustainable, eco-friendly and stable power supply, as it cannot be efficiently integrated with decentralized and localized power generation systems and renewable energy sources. The result of this paper shows that decentralized and localized power generation systems are located close to end-users which decrease the transmission and supply cost of electricity. Innovative technologies allow the decentralized and localized power generation systems to be integrated with renewable energy sources which help to reduce the cost of utility services and provide clean energy.

Globally, the transportation system is transforming from a fossil-based to an electrification system. Some countries are leading in the transformation process. Some countries are rapidly catching up to become market leaders in developing and introducing new techniques and equipment that support the transformation process in their countries. In contrast, others are still relying on their old fossil-based system or could not have enough understanding of how to deal with this complex transformation of the transportation system.

The electrification of the transportation system is not an isolated system that can be handled as a single technological element. It is a group of multiple technologies, political, societal, and economic sub-systems each of these sub-systems is embedded in each other, forming the whole system. Therefore, it is important to see and manage the system from a holistic perspective to transform the transportation electrification system efficiently. We have selected eight countries from three different continents – Asia (China, India), Australia, which is a country and continent, and Europe (Germany, Norway, Slovenia, Sweden, and the UK) to explore the transformational process of transportation electrification based on each countries’ conditions. We have chosen these continents as they are diversified in adopting transportation electrification system solutions.

Our main conclusions are that the political processes and political decisiveness are the most important, followed by the societal and economic, with technology as the fourth. The other three are difficult to obtain without dedicated and determined political decision-makers. Political decision-makers need to use economic means to support the transformation in society and industry to balance the economic disadvantage of electric systems until they pass the cost disadvantage turning point. Technology is no longer a significant barrier as it was about 20 years ago. Now, technology is available, although it can be improved. The important part is to understand how to utilize the existing technology efficiently to transform the old fossil-based transportation system into new electrification of the transportation system. Without clear and strong political support, the industry cannot be expected to initiate, finance, take risks, and take the lead in this global societal transformation.

The main objective of this paper is to develop a readiness index model that can serve as an analytical tool for exploring the achievements of electrification of transportation systems. We have applied this readiness index model to evaluate the readiness positioning of China, Norway, and Sweden towards transport electrification. We have chosen these three countries as they represent diversity among countries that are in the process of adopting electrified transport system solutions. Our developed readiness index model has four key dimensions, technological readiness, political readiness, societal readiness, and economic readiness. The embeddedness of all four dimensions in one model provides a multi-perspective way of analyzing and evaluating the readiness levels of countries moving towards transforming the transportation system. Therefore, we named the model a “multidimensional readiness index.”

The electric road system is an emerging concept in this modern era. The advancement of technology has made it possible to give this concept a real shape (electric road system). However, the energy provided to the electric roads is still produced by non-renewable energy sources, which are completely unhealthy and harmful for society. Furthermore, the traditional grid is not suited to integrate with decentralized/localized energy generation and distribution systems. It is an ineffectual and environmentally extravagant system. Therefore, the preliminary contribution of this research is to introduce a decentralized/localized energy generation system based on renewable energy sources and energy distribution to electric roads through the emerging technology of microgrid and smart grid systems, which have the capability to integrate with renewable energy sources easily. Thus, producing electricity with renewable energy sources is environmentally friendly, less expensive, and available without charges. However, each source of energy has some environmental impacts and cost differences. A brief description of the environmental and cost impact of renewable energy sources (wind, solar) is also presented.

Driving simulators are established tools used during automotive development and research. Most simulators use either monitors or projectors as their primary display system. However, the emergence of a new generation of head-mounted displays has triggered interest in using these as the primary display type. The general benefits and drawbacks of head-mounted displays are well researched, but their effect on driving behavior in a simulator has not been sufficiently quantified.

This article presents a study of driving behavior differences between projector-based graphics and head-mounted display in a large dynamic driving simulator. This study has selected five specific driving maneuvers suspected of affecting driving behavior differently depending on the choice of display technology. Some of these maneuvers were chosen to reveal changes in lateral and longitudinal driving behavior. Others were picked for their ability to highlight the benefits and drawbacks of head-mounted displays in a driving context.

The results show minor changes in lateral and longitudinal driver behavior changes when comparing projectors and a head-mounted display. The most noticeable difference in favor of projectors was seen when the display resolution is critical to the driving task. The choice of display type did not affect simulator sickness nor the realism rated by the subjects.

Performance based standards (PBS) is an effective regulator policy which can address variation complexity in vehicle combinations. This paper investigates aspects of using computer simulation and mathematical models to assess the performance of vehicle combinations in low speed manoeuvring, and in particular roundabouts. A set of 22 vehicle combinations, including existing conventional heavy vehicles as well as prospective high capacity vehicles, is used to study the effects of turn angle and road surface conditions on the friction demand and swept path measures. Simulation results suggest that the friction demand measure is dependent on the available grip. This makes it hard to interpret and may not be suitable in the PBS framework. The swept path measure is relatively unaffected by friction levels, and can hence be calculated with simple and robust expressions not considering the road interaction. However, turn angle affects the swept path measure considerably, and should be addressed when designing the PBS scheme implementation into the legislations.

Several different heavy vehicle combinations are allowed on the Swedish road network. A commonly seen combination is the tractor and semi-trailer combination with a maximum total length of 16.5 meters. The legal limitation on the total length of the combination has led to the use of a short tractor to make space for more goods on the trailer. There is a concern that the shortness of the tractors will have a negative consequence on traffic safety and the ability to negotiate uphills. The short wheelbase of the tractor and the weight imbalance between the tractor and the semitrailer could be an issue when braking and negotiating turns. 

This study was ordered by the Swedish Transport Agency to investigate the traffic safety aspects and hill-climbing problems of certain heavy vehicle combinations. The concerns raised should be investigated from a vehicle dynamical point of view for the vehicle combinations in question and compare them with other common vehicle combinations through a simulation study. 

A set of tractor and semitrailer combinations have been simulated in severe conditions and maneuvers to investigate the vehicle response and its dependencies with respect to the wheelbase of the tractor, coupling length, fifth wheel lubrication, and road surface conditions. Whenever meaningful, a comparison was made with a Nordic combination (truck and full trailer) as well as a B-double combination (tractor, link trailer, and trailer). 

The overall result of the simulation study is that the tractor and semitrailer combination is a stable combination, which outperforms the longer and heavier Nordic and B-double combinations in all the measured situations and maneuvers where comparison is meaningful. Furthermore, the wheelbase of the tractor seems to have a very minor effect on the performance of the vehicle combinations.

In-vehicle technologies are essential for vehicle safety. This project, Quantitative Driver Behavior Modeling for Active Safety Assessment Expansion (QUADRAE), addresses two crucial components of the technology development process: driver models and simulation methodology. Together, they have provided the industrial partners with state-of-the-art tools for system development and testing, facilitating the development of innovative technologies to improve traffic safety. The main objectives of the project were to:

• develop and validate models of driver behavior needed in current and future simulation tools for virtual testing of active safety and automation
• carry out prioritized virtual tests to estimate the safety benefit of a system, tune system parameters, and explore potential outcomes in scenarios when the system is active
• learn more about the best methods for performing virtual testing using driver models

As a result of the project, the partners now have an established virtual simulation framework using Predictive Processing (PP) as a general paradigm for modeling driver behavior. The modeling, based on the latest knowledge and ideas about human behavior in driving, draws on extensive research using volunteer drivers as study participants. Data from both controlled experiments and naturalistic driving were used to develop and validate the models. These models are already being used by the industry partners as part of their virtual safety assessment toolchain, to develop advanced driver support systems. The data will continue to be used by the project partners in industry and academia to develop future driver models (which will, in turn, foster improved driver support systems).

The Swedish National Road and Transport Research Institute (VTI) has been commissioned by the Swedish Government to “contribute to the creation of knowledge regarding a rapid, smart and socioeconomically efficient electrification of the transport sector”. This report presents the part of the commission that describes a general analysis of the interaction between the energy system and the transport system, what obstacles there are and what solutions can contribute to increased electrification of transport. This part of the assignment includes good examples from other countries. 

Transport and energy have always been closely linked sectors. What is changing now, is not only the connection between the sectors, but also their nature; while the transport sector has historically mainly consumed oil products, global climate measures will drive the transport sector towards a stronger link to electricity. Therefore, the transition from oil-based transport to electricity-based transport is as much about sector changing within the energy sector as between energy and transport sectors. To handle this transition requires a conversion of both systems. The report describes the implications of the transport sector’s change on the energy system and the roles of various actors in the change. In addition, good examples from four other countries – China, the USA, Norway and the Netherlands – are highlighted. When transitioning, there are some policy aspects that are important to take into account, such as technology and behavior change, changes in the sectors and overlapping political goals.

Establishing interoperability is an essential aspect of the often-pursued shift towards Model-Based Systems Engineering (MBSE) in, for example, aircraft development. If models are to be the primary information carriers during development, the applied methods to enable interaction between engineering domains need to be modular, reusable, and scalable. Given the long life cycles and often large and heterogeneous development organizations in the aircraft industry, a piece to the overall solution could be to rely on open standards and tools. In this paper, the standards Functional Mock-up Interface (FMI) and System Structure and Parameterization (SSP) are exploited to exchange data between the disciplines of systems simulation and geometry modeling. A method to export data from the 3D Computer Aided Design (CAD) Software (SW) CATIA in the SSP format is developed and presented. Analogously, FMI support of the Modeling & Simulation (M&S) tools OMSimulator, OpenModelica, and Dymola is utilized along with the SSP support of OMSimulator. The developed technology is put into context by means of integration with the M&S methodology for aircraft vehicle system development deployed at Saab Aeronautics. Finally, the established interoperability is demonstrated on two different industrially relevant application examples addressing varying aspects of complexity. A primary goal of the research is to prototype and demonstrate functionality, enabled by the SSP and FMI standards, that could improve on MBSE methodology implemented in industry and academia.

This report describes the work of work packages 6 and 8 in the Vinnova-funded Smarta gator project. Based on architectural descriptions, three different VR environments have been created – so-called “digital twins” of a currently existing street environment in Stockholm, as well as two different possible future versions of the street environment. The simulated environment can be experienced by pedestrians in VTI’s pedestrian simulator, and alternatively also by motorists through co-simulation with another driving simulator. The two possible visions for the future were evaluated from a pedestrian perspective through a workshop with 30 subjects in VTI’s pedestrian simulator in Linköping. The participants’ answers clearly show that the experience of security, priority and well-being increased in the smart environments compared with the original environment. 

However, the readability of the street space was experienced in the smart environments somewhat degraded compared to the original environment. One explanation may be that many people recognize the original environment because it is a relatively common type of street – wide lanes for cars, curbside parking and sidewalks, while the smart environments are structured in a different way, which may need additional experience to understand this “new type” of street. 

Overall, the study demonstrates how street spaces can be created that are experienced as more pleasant and safer by prioritising pedestrian and bicycle traffic through a larger area dedicated to walking, cycling and accommodation than for motor traffic. The creation of living spaces and social functions along the street also had a positive effect on the experience of the street space. Placing trees and greenery along the street is in addition to the ecological benefits also important for the well-being and experience of the street space. 

It is concluded that VR simulation can be a useful tool for assessing various design solutions at an early stage. VTI’s pedestrian simulator is equipped with a state-of-the-art image system, but the restricted area of 3x6 meters is too small to allow for a person to easily walk around the urban environment. Autonomous pedestrians, controlled by the game engine Unreal Engine, were perceived by most subjects as very realistic, and they contributed to the illusion of being in place in the environment.

All-season tyres have previously not been approved for use as winter tyres in Sweden but are now allowed after a change of regulations in 2019. To compare the grip of this type of tyre with regular winter and summer tires, brake tests were conducted for 14 different all-season tyres on packed snow and ice, as well as on dry and wet asphalt. The tyres were selected to be representative of the available all-season tyres on the Swedish market. The results show large differences in braking grip between different all-season tires. Some tyres perform more like European non-studded winter tyres, and others more like summer tyres, which seems to be a conscious choice by the various manufacturers. On average, the braking distance of all-season tyres on snow is clearly longer than that of both Nordic and European non-studded winter tyres, and although there are all-season tyres that are similar to European winter tyres on snow, others perform significantly worse. On ice, the braking grip of all-season tyres is much worse compared to the Nordic non-studded reference tyre.

Our assessment is that the ice grip is generally too poor to constitute a safe alternative on Swedish winter roads, and that one of the winter-approved all-season tyres performed just as bad as one of the summer tyres on ice is remarkable. There is a correlation between low rolling resistance and poor ice grip, which indicates that measures to reduce rolling resistance can have a negative impact on the ice grip of this type of tyre. Braking performance on dry and wet asphalt for all-season tyres are widespread, with the best all-season tyres performing equally with summer tyres, and the worst being about the same level as the best of the Nordic winter tyres. We can therefore not recommend all-season tyres as an alternative to winter and summer tyres.

Tyre friction properties of 21 different heavy vehicle tyres have been measured on smooth ice and dry asphalt using a dedicated flat-bed machine. The purpose of the measurements was to study characteristics of typical heavy vehicle tyres, and to provide representative models for heavy vehicle dynamic simulations for both high and low friction conditions, with focus on lateral friction forces. The results reveal large differences of the cornering stiffness between new and worn tyres, where lower tread depth results in substantially higher stiffness. Cornering stiffness values on smooth ice and asphalt are very similar, suggesting that rubber and carcass stiffness rather than the friction level determines this property. Also, peak friction level on asphalt and relaxation length exhibits higher values for worn tyres compared to new. The measured data is currently being analysed in more detail with the purpose of creating standardized tyre models that can be used for PBS simulations.

Two different metrics quantifying model and simulator predictive capability are formulated and evaluated; both metrics exploit results from conducted validation experiments where simulation results are compared to the corresponding measured quantities. The first metric is inspired by the modified nearest neighbor coverage metric and the second by the Kullback-Liebler divergence. The two different metrics are implemented in Python and in a here-developed general metamodel designed to be applicable for most physics-based simulation models. These two implementations together facilitate both offline and online metric evaluation. Additionally, a connection between the two, here separated, concepts of predictive capability and credibility is established and realized in the metamodel. The two implementations are, finally, evaluated in an aeronautical domain context.

High Capacity Transport (HCT) is part of Sweden’s attempts towards a more efficient transport system. HCT vehicles are heavier and/or longer than conventional heavy vehicles and can carry more load per vehicle, resulting in less fuel consumption and emissions. In Sweden the legal length and weight limits for heavy vehicles are 25.25 m and 64 t. Also, from April 2018, heavier vehicles up to 74 t have been allowed on parts of the road network with a new bearing capacity named BK4. Introduction of vehicles longer than 25.25m is currently under consideration. In the neighboring country, Finland, the weight limit for heavy vehicles was increased to 76 t in 2013, and longer HCT vehicles up to 34.5 m are allowed on most of the road network since 2019. After allowing HCT vehicles in Sweden, regulations concerning heavy vehicles access to road network have been modified and a PBS based regulation for 74 t vehicles have been introduced. PBS stands for performance based standards, under which the required performance from the vehicles is regulated, instead of limiting their length or weight. The purpose of the PBS II project has been to contribute to further development of the PBS scheme in Sweden and to support its implementation. One important aspect which required further investigation was the effect of tire characteristics on the performance of the HCT vehicles. Also, the assessment procedure of the HCT vehicles and a corresponding tool for it, demanded further developments. These issues have been addressed in the PBS II project, resulting in standard tire models for assessment of HCT vehicles, as well as an improved open access PBS tool.

A commonly seen vehicle combination on the European road network is the tractor-semitrailer with a maximum legal length of 16.5 m. In Nordic countries longer tractor-semitrailers are allowed, which makes tractors with larger wheelbase an appealing option. Concerns have been raised that shorter tractors have poorer performance and are involved in more accidents than the Nordic equivalents, especially in winter conditions. To answer the raised questions and concerns, this paper investigates the effects of a tractor wheelbase length on performance of a vehicle combination, as well as other influencing factors such as lubrication of the fifth when, loading condition and road friction level. Six tractor-semitrailer combinations with different wheelbases and axle configurations are modeled and compared. Nordic (truck-dolly-semitrailer) and B-double (tractor-link trailer-semitrailer) combinations, which are common in Nordic countries, are also used as reference vehicles in the comparison. Three maneuvers are simulated to provoke dangerous situations, namely braking with all wheels in a curve, engine braking in a curve and a fast single lane change. The results show that wheelbase alone does not have a major role in the outcome of the simulations, but a combined influence of axle configuration, wheelbase, fifth wheel position and axle loads determines the vehicle performance. Factors such as existence of a working anti-lock braking system or lubrication of the fifth wheel have a large effect on the vehicle performance, under the tested conditions.

A methodology for the generation of representative driving cycles is proposed and evaluated. The proposed method combines traffic simulation and driving behavior modeling to generate mission-based driving cycles. Extensions to the existing behavioral model in a traffic simulation tool are suggested and parameterized for different driver categories to capture the effects of road geometry and variances between drivers. The evaluation results illustrate that the developed extensions significantly improve the match between driving data and the driving cycles generated by traffic simulation. Using model extensions parameterized for different driver categories, instead of only one average driver, provides the possibility to represent different driving behaviors and further improve the realism of the resulting driving cycles.

The vertical dynamic vehicle–track interaction in a railway crossing is simulated in the time domain based on a moving Green’s function approach in combination with an implementation of Kalker’s variational method to solve the non-Hertzian, and potentially multiple, wheel–rail contact. The method is demonstrated by calculating the wheel–rail impact load and the sleeper–ballast contact pressure for a hollow-worn wheel profile passing over a nominal crossing geometry. © 2020, Springer Nature Switzerland AG.

Crash test dummy kinematics is commonly obtained from high-speed video recordings or other opticalmethods. The present study evaluates a cost-efficient sensor system combining gyros and accelerometers toderive the kinematics of different parts of a dummy. This evaluation was done on the newly designed humansurrogates, the Seat Evaluation Tools (SET) 50F and 50M, developed for low severity rear impacts and hereequipped with gyros at four locations

Railway noise and ground-borne vibration induced by wheel–rail impact loads are generated by discrete wheel/rail surface irregularities or local deviations in the nominal wheel–rail contact geometry. On the running surface of a rail, a discrete irregularity can be inherent to the railway design, for example at crossings or insulated joints. On the wheel or rail, the irregularity could also be the result of surface damage due to rolling contact fatigue cracking or a consequence of wheel sliding without rolling. This review describes the mechanisms of wheel–rail impact generated by wheel flats, rail joints and crossings. These can be a source of locally increased noise and vibration levels and increased annoyance, as well as of damage to vehicle and track components. The wheel–rail excitation at such irregularities, as indicated by the vertical wheel centre trajectory, leads to an abrupt change of momentum, potentially causing a momentary loss of wheel–rail contact followed by an impact on the rail. The resulting loading is a transient and often periodically repeated event exciting vibration in a wide frequency range with most of the energy concentrated below about 1 kHz. For the numerical prediction of high-magnitude transient loading and situations potentially leading to loss of contact, a non-linear wheel–rail contact model is required, implying that the simulation of contact force is carried out in the time domain. To avoid the need for large, computationally expensive models, a hybrid approach has been developed in which the time history of the contact force is transformed into an equivalent roughness spectrum; this is used as input to frequency-domain models for the prediction of noise and vibration. Since the excitation mechanism is similar to that for rolling noise, the same types of measures to mitigate wheel and track vibration can be applied. However, the main priority should be to control the irregularity by design and regular maintenance.

In 2020, the Swedish Transport Administration received a governmental assignment to analyze the conditions and plan for the expansion of electric roads. In the assignment, an analysis was made regarding a potential degree of utilization of electric roads in Sweden, based, among other things, on the development of heavy electrified road transport. 

The degree of utilization is a central factor in being able to understand the consequences, for example in terms of environmental benefits and socio-economic profitability, that the establishment of electric roads can entail. The utilization rate in the Swedish Transport Administration’s report was estimated at 25% in the event of a full expansion of the electric road network by the year 2040. Due to external developments and the rapid technological development in the electric road market, other European countries have made similar investigations which resulted in other utilization rates. Therefore, there was reason to renew the analysis of the potential degree of utilization of electric road system in Sweden. 

To be able to determine whether the utilization rates produced in the Swedish investigation still stood, a comparison was made between these calculations and the reports of four other European countries, Germany, France, Great Britain and the Netherlands. The aim was to analyze the importance and influence of various factors on the degree of utilization of electric roads. The goal was to present a method to be able to make comparisons regarding included factors as well as calculations of the degree of utilization based on selected factors. 

This report proposes different approaches for estimating utilization rate, by exemplifying different estimates based on different input factors and calculation basis. The report also includes a sensitivity analysis to demonstrate how different assumptions can produce different utilization rate results. 

The investigation shows that detailed information from several sources is required to be able to make reliable estimates about the utilization rate of electric roads. Based on the sensitivity analysis carried out, it becomes clear that Swedish long-distance transport accounts for the single greatest use of the electric road. It will therefore be important to examine which behaviors in the vehicle fleet that are required to switch to electric road operation, as these factors are decisive for the utilization rate.

The government has commissioned the Swedish National Road and Transport Research Institute (VTI) to “contribute to the building of knowledge around a fast, smart and economically efficient electrification of the transport sector”. This report focusses on the part of the mission that deals with conducting pilot projects and developing models for how data, in practice, can be made available, shared and utilized in the best way to optimize planning, development, operation for charging infrastructure and business models. 

The report provides a description of existing technologies for charging electric vehicles, important user perspectives, and how business models and systems for charging infrastructure can be modelled. 

The report focuses on data sharing and describes how actors today share data and what difficulties they see with data sharing. This includes, among other things, data availability, sharing and utilization, as well as how the actors want it to work going forward. A major challenge concerns data availability, where actors partly see problems with getting access to data and partly are hesitant to want to share their own data. Often, it is about privacy issues and regulation according to the GDPR. 

The importance of a well-functioning collaboration between the energy and transport sectors has been highlighted in previous reports from this assignment. 

The importance of digitalization and digital infrastructure that connects these sectors is particularly emphasized in this work. Digitalization is needed to streamline planning, development and operation of the infrastructure that an electrified transport system requires. The modeling done in this part of the assignment deals with transport modeling and energy modeling as well as development to make the models interact.

This study presents a solution for connecting system simulation and aircraft concept development using solely open standards. An easy-to-use optimisation framework for aircraft concept development is created with the help of the Modelica, Functional Mock-up Interface (FMI), and System Structure and Parameterization (SSP) standards, and the open source tools OpenModelica and OMSimulator. The framework allows for conceptual aircraft design accounting for transient phenomena by means of standardised integration of dynamic simulation models of aircraft subsystems. The framework is applied to an industry-relevant use case concerning the concept development of a generic fighter aircraft. The generality and modularity of the framework and its straightforward implementation enables tailoring of the optimisation goals to the user needs and requirements. The adoption of industry-wide standards allows for the inclusion of system simulation models developed in the modelling tool best suited for each discipline, thus integrating dynamic system simulation already at the aircraft conceptual design stage.

This paper refines the two-regime transient theory developed by Romano et al. [Romano L, Bruzelius F, Jacobson B. Unsteady-state brush theory. Vehicle Syst Dyn. 2020;59:11-29. DOI: 10.1080/00423114.2020.1774625.] to include the effect of combined slip. A nonlinear system is derived that describes the non-steady generation of tyre forces and considers the coupling between the longitudinal and lateral characteristics. The proposed formulation accounts for both the carcass and the bristle dynamics, and represents a generalisation of the single contact point models. A formal analysis is conducted to investigate the effect of the tyre carcass anisotropy on the properties of the system. It is concluded that a fundamental role is played by the ratio between the longitudinal and lateral relaxation lengths. In particular, it is demonstrated that the maximum slip that guarantees (partial) adhesion conditions does not coincide with the stationary value and decreases considerably for highly anisotropic tyres. The dissipative nature of the model is also analysed using elementary tools borrowed from the classic theory for nonlinear systems. A comparison is performed against the single contact point models, showing a good agreement especially towards the full-nonlinear one. Furthermore, compared to the single contact point models, the two-regime appears to be able to better replicate the exact dynamics of the tyre forces predicted by the complete brush theory. Finally, the transient model is partially validated against experimental results.

The ongoing digitalization of the transport system, including automated vehicles, entails a paradigm shift. The development of vehicles with advanced driver support, automated functions, and self[1]driving vehicles is now an obvious use in the transport system. Thanks to the introduction of new sensors in the vehicles and connectivity, there is a complement that allows automation functions that can support the human driver with the driving task in all or parts of the journey. On the other hand, it should be clear that today's transport system and infrastructure have been designed to maneuver vehicles with the help of human drivers and their associated limitations and capabilities. 

The project aims, from a road maintenance perspective with a focus on the state road network, to describe the current state of knowledge regarding existing and possible adaptations of the digital and physical infrastructure to provide support for vehicles with automated functions. The project also aims at long-term knowledge building. 

Data has been collected via literature studies and, above all, obtained from studies of ongoing and executed relevant projects, both national and international. Furthermore, much knowledge has been gathered through the authors' networks and their participation in relevant international and national groups. A workshop with relevant commercial actors has also been conducted within the project.

The report presents a summary of existing data for current requirements and limit values, historica lfeedback, external monitoring and background facts, as well as recommendations for measurement method, measures and limit values with regard to consequences and feasibility. It can be noted that evidence-based proof is often lacking for current rules and limit values. Tire road friction is a complicated property that is difficult to measure as it depends on so many factors. Therefore, the recommendations will often be to use current methods and limit values. For motorways it is proposed to continue to use the skiddometer principle and SFT (Surface Friction Tester) with specifications according to the previous standard. For road markings it is proposed to use SFT where possible, otherwise PFT (Portable Friction Tester) and for pedestrian and cycle paths it is proposed to use PFT.As a limit value it is recommended to use 0.50 at 70 km / h (as before). From comparative measurements it can be stated that 0.55 at the measuring speed 40 km / h corresponds to 0.50 at 70 km/h. Furthermore, measurements indicate that PFT and SFT measurement data can directly replace each other with certain reservations. In order to control the grip even better, it is reasonable to place demands on the macro texture, as a complement to the friction measurement at higher permissible speeds, for example above 70 km/h.

One2Many, the title of this report, refers to remote operation of vehicles where an operator handles several vehicles simultaneously. This may increase efficiency and opportunities for profitability. The objective of this report is to identify essential and relevant developments of the regulatory framework, as well as business models and working conditions for support of safe and sustainable introduction of a single person’s remote operation of multiple vehicles. 

As a starting point, this report describes the taxonomy used and a state-of-the-art study. Most literature deals with technical challenges around remote operation while non-technical challenges, as well operation of multiple vehicles, are poorly covered. This report aims at addressing this gap by considering non-technical aspects for remote operation. 

Legal aspects are described and analysed, resulting in recommendations for next steps for legislation and regulation. Furthermore, business models and working environment are discussed, taking advantage of two real world use cases: goods transport (Einride trucks), and public transportation (Ride the Future automated shuttles). 

One2Many summarises regulatory considerations in a Memorandum, and additionally concludes that: 

• Research is needed regarding legal challenges for the three different modes of remote operation (remote driving, remote assistance, remote supervision) and how to address them in future regulation to best deal with safety concerns and to support remote operation. Liability issues and concerns also need to be handled. 

• The main advantage of introducing remote operating for several vehicles per operator will most likely be uptime. The employee cost is foreseen to decrease, but potential surrounding functions need to be studied in order to determine if the cost of personnel actually would go down. 

• Several working environment considerations should be further discussed, e.g. regarding what type of controls would be most effective and safe to use, and whether it matters if an operator has a background as driver of conventional vehicles.

The DeDT2 project is an extension of the DeDT project. The design tool developed in DeDT had limitations from a use case perspective. Thus, more functionality was desired. DeDT2 addresses these demands and is a more versatile tool for creating the simulated environment. The scope of DeDT2 has been focused on the creation of roads and crossroads, not on the environment outside the road surface. DeDT2 has evolved to a tool which can create ordinary road segments of different characteristics and put them together to drivable entities. Included in the scope is preparing 3D assets, developed during the DeDT project, to be more suitable in simulation environments. The result from DeDT2 is a second step towards designing a tool for the creation of more complete simulated driving environments.

Five carefully selected feasibility studies have been initiated by VTI as part of the strategic investment “Ride the future” linked to future mobility solutions. The title of the feasibility studies is as follows: 

▪ Data processing and visualization of mobile air quality measurements. 

▪ SUMO and Unreal Engine for co-simulation. 

▪ Exploring spatio-temporal accessibility in Lambohov: a pre-study. 

▪ The importance of the road surface for vibrations and comfort in slow vehicles. 

▪ Infrastructure needs at bus stops.

 This report contains a brief description of the studies and the more detailed report can be found in the appendix.

Syftet med den här förstudien var att undersöka förutsättningar, behov och nyttor då olika simulatormiljöer för järnväg integreras för att skapa en helhet. HUS står för Helhet i Utvecklad Simulatormiljö, men syftar samtidigt till en fysisk miljö inrymd i Trafikverksskolan i Ängelholm. Målet för förstudien var att skapa förutsättningar för samt initiera en plattform där olika simuleringsverktyg, nödvändiga för testning, träning och forskning relaterad till järnvägstrafik, kan användas både var för sig eller kopplas samman. Ett första steg är att koppla samman två olika simulatorsystem för att kunna demonstrera idén. 

Projektet är ett uppdrag där Trafikverket och specifikt Trafikverksskolan har anlitat VTI. Metoderna som har använts är fokusgrupper med olika behovsägare samt mjukvaruutveckling tillsammans med systemexperter från Trafikverket. 

Resultaten visar ett stort behov av hopkopplade simulerade miljöer för träning, utbildning och forskning inom järnvägsområdet. Många roller har behov av att träna tillsammans i säkra och kontrollerbara miljöer för att bättre förstå varandras arbetssituation. Forskare behöver också repeterbara, kontrollerbara och säkra miljöer som inte är säkerhetsklassade. En första simulerad hopkoppling av VTI:s tågsimulator och Trafikverkets Järnvägssimulator har genomförts för att demonstrera möjligheterna och nyttan med att integrera miljöerna. Utmaningarna ligger främst i att hantera säkerhetsfrågor och skapa en samverkansform med den kommersiella tillverkaren av Järnvägssimulatorn.

This PM reports the results of a supplementary work on a previously developed model for prediction of future competence and resource needs for Swedish railbound infrastructure. In this PM, the choice of complementary measures on the prediction model is justified and a description of performed work is given. Finally, the forecasts of future competence and resource needs are updated and discussed. 

To determine the focus of efforts made as part of the current project, information from the Swedish Transport Administration long-term budget planning was combined with existing knowledge on the cost share of planned infrastructure measures that is linked to personnel with railway-specific competence. Efforts with potential to have a significant impact on the forecast were prioritised. Finally, it was decided to concentrate efforts in the current project on the modelling of (1) the construction of new railway infrastructure, (2) maintenance and (3) measures related to the implementation of the European Rail Traffic Management System (ERTMS).

This feasibility study is an interdisciplinary collaboration between three research institutes (VTI, Chalmers University of Technology and RISE) and a railway brake manufacturer (Faiveley Transport Nordic). Senior researchers specialized on numerical modelling of friction brakes and on particle matters (PM), are combined with expertise in the field of train driving simulation to reduce railway’s impact on environment and human health. The train driving simulator of VTI is further developed to account for the wear generated at the brake blocks and in the wheel‒rail contact. A literature study that focuses on prediction of railway particle emissions is presented

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature.

Measurement methods to determine the rolling resistance of tyres during different operation conditions are essential in the work towards more energy efficient vehicles. One of the influential parameters is the tyre temperature distribution, which has a large impact on the rolling resistance. Today, the standardised test procedure to measure rolling resistance is steady-state measurement on drums. However, the steady-state temperature on a drum is not the same as the temperature during ordinary driving conditions. The aim of this work is to develop a measuring method that enables to set a desired measurement temperature, which would create the possibility to study the relationship between tyre temperature and rolling resistance in more detail. The measurement method was developed by the use of a flat track equipment but should be applicable to other rolling resistance measurement equipment such as drums. The resulting method gives a repeatable tyre temperature and rolling resistance and can be used for measurements on tyres heated to a chosen measurement temperature. 

Reducing the rolling resistance for future vehicle designs creates a possibility to reduce the fuel consumption and make the future vehicles more economical and ecological. For electric vehicles it is also an enabler to increase their driving range per charge. When optimising for reduced rolling resistance, contradictory requirements such as force generation for maintaining safety and performance need to be considered. Furthermore, it is important to include both the effects of road surface and vehicle, to avoid sub-optimisation regarding only the tyres. A cross-functional conflict on the component level is well known, in form of energy consumption versus wet grip (traffic safety). On the system level, different wheel settings to optimise energy consumption conflicts with vehicle dynamical properties related to traffic safety, such as stability or steer response. The long term vision of the work presented is to create tools for more energy efficient vehicles by reducing the rolling resistance during driving. The first part is to establish a credible measurement method for rolling resistance on road under controlled conditions (lab environment). Today’s existing measurement methods on rolling resistance under laboratory conditions commonly utilise a rotating drum, whose curved surface affects the results. Therefore, rolling resistance influence of vehicle settings such as camber or toe angles is difficult to assess using standard methods, and there is a need for measurements using a more realistic contact patch, which would need a flat surface. The existing unique tyre testing facility at the Swedish National Road and Transport Research Institute, VTI, is used as a base for developing the new rolling resistance set-up. The tyre test facility is today used to determine tyre characteristics such as brake and steering forces. The method to measure rolling resistance with this equipment under highly controlled conditions is under development, and some preliminary results are presented.

For at least 50 years, the interest in understanding and reducing the rolling resistance of pneumatic tyres has been growing. This interest is driven by the need to reduce vehicle fuel consumption and CO2-emissions, for environmental and economic reasons. The amount of rolling resistance generated depends on the vehicle type, tyre properties and operating conditions. The main objective of this literature review is to provide an overview of the most influential operating conditions with respect to rolling resistance, their effects and their connection to different measurement techniques. The examined operating conditions are the inflation pressure, the temperature, the curvature of the test surface, the load, road surface, speed, torque, slip angle and camber angle. In addition, the definition of rolling resistance is investigated, which shows lack of harmony in the literature. There are important areas where little research can be found and where further research would be valuable. Examples of such areas are effects of the torque, slip angle and camber angle on rolling resistance, thorough comparison between flat-surface and drum measurements, effects of temperature difference between laboratory measurements and actual driving on rolling resistance and evaluation of Unrau’s formula for temperature correction of rolling resistance measurements.