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.

Motion parallax due to the driver’s head movement have been implemented and tested in VTI Driving Simulator III. An advanced camera-based system was used to track the head movements of the driver. The output from the tracking system was fed to the simulation software, which used low-pass filtering and a forward prediction algorithm to calculate an offset. The offset was then used by the graphics software to display the correct image to the driver.

The effects of driving with motion parallax in the simulator were also observed by an initial study. During the experiment, the subjects caught up with several slower vehicles which forced the driver to make an overtaking maneuver. Oncoming traffic forced the subject to search for a suitable gap for overtaking. The study also included a speed perception test. The results from the study showed no difference in lateral positioning when running behind a slower vehicle nor in speed perception with and without motion parallax.

The study in this publication investigates the need and potential for night-time scenarios in driving simulators, determines how such night-time scenarios could be reproduced and identifies the objects most important to reproduce. Although on average 12 out of every 24 hours are dark and considering that most situations are more demanding for drivers in dark conditions, simulations of driving scenarios with different degrees of darkness are not common. The project work comprised a pre-study that involved an investigation of the need and potential of night-time scenarios with the help of input from different stakeholders, consolidation of what is known up to now through benchmarking and state of the art, and a review of available technical solutions. The objective was to identify pros and cons with existing solutions and aspects that are important to consider in order to reproduce the most important components in realistic night-time scenarios. Based on the results, six important use cases were identified and two of these (‘Driver fatigue’ and ‘Objects without light sources’) were studied in more detail. It was concluded that for night-time scenarios there is enough darkness in general in the simulator environment. The question is whether it is possible to create sufficient contrast for objects that are meant to be observable. For daytime scenarios, the light levels in the simulator are clearly unrealistically low and this limitation might even trigger unwanted sleepiness.

Projektet har syftat till att visa på möjligheterna för att göra studier av fotgängarbeteende genom att nyttja modern Virtual Reality-teknik. Under projektets gång har en VR-studio byggts upp på VTIs kontor i Linköping. Till denna miljö har det utvecklats mjukvara som kan användas för att studera beteendet hos fotgängare i tänkta trafiksituationer. Simulatorn är utrustad med blickmätningssystem vilket gör att det går att både mäta och interaktivt visualisera var användaren har sin uppmärksamhet i varje ögonblick. Det går att uppleva vad användaren ser i den virtuella världen ur både ett förstapersons- och tredjepersonsperspektiv. Det finns ett särskilt läge för Mixed Reality, det vill säga ett läge där en verklig videoström kombineras med den datorgenererade omgivningen. För att visa nyttan med simulatorn så har ett scenario utvecklats. I detta scenario kan en användare uppleva hur det är att interagera med olika fordon, både självkörande och andra.

This publication is a review of available technologies for tracking the user in virtual reality systems. Tracking the user location is important for generating views that adapts to the user’s movements.

This review begins with the basic terms used in virtual reality in general. Followed by the important characteristics for tracking equipment. This is followed by a chapter on the fundamental algorithms used for position calculations. Then the most common technologies with their advantages and disadvantages are presented. The text conclude with how these technologies are used in automotive virtual reality.

This paper describes the design of a video see-through augmented reality system for active safety testing. The development is explained in detail, with focus on the design considerations for the different subsystems. It is shown that it is possible to build a system using available commercial off-the-shelf components, while still maintaining the performance needed for the intended application. Accuracy and resolution requirements of the tracking systems are discussed along with measurement methods. We also examine how to use the hardware efficiently to minimize latency and a device to measure and quantify end-to-end latency has been developed.

Head mounted displays (HMDs) is an emerging technology and the availability of affordable systems is growing fast. Replacing projector and large screen solutions with head mounted displays may appear as an appealing solution. However, inherent properties and technical limitations of these systems need to be understood and considered before making the leap to virtual reality.

This paper outlines some of the most fundamental limitations of head mounted displays relevant to this context, both from a technical and human factors perspective. Desirable properties of scenarios and types of studies are deduced, based on these limitations. Finally, a meta analysis is performed on the feasibility of transferring simulator studies found in the literature to platforms with head mounted displays. The results suggest that a noticeable amount (40%) of the investigated simulator studies could likely have been performed with head mounted displays. This number could be increased further with technical advances in display resolution, display technology, reduction in latency, etc.

This paper presents a comparative study of driving behavior when using different virtual reality modes. Test subjects were exposed to mixed, virtual, and real reality using a head mounted display capable of video see-through, while performing a simple driving task. The driving behavior was quantified in steering and acceleration/deceleration activities, divided into local and global components. There was a distinct effect of wearing a head mounted display, which affected all measured variables. Results show that average speed was the most significant difference between mixed and virtual reality, while the steering behavior was consistent between modes. All subjects but one were able to successfully complete the driving task, suggesting that virtual driving could be a potential complement to driving simulators.

This paper presents a comparative study of driving behavior when using different virtual reality modes. Test subjects were exposed to mixed, virtual, and real reality using a head mounted display capable of video see-through, while performing a simple driving task. The driving behavior was quantified in steering and acceleration/deceleration activities, divided into local and global components. There was a distinct effect of wearing a head mounted display, which affected all measured variables. Results show that average speed was the most significant difference between mixed and virtual reality, while the steering behavior was consistent between modes. All subjects but one were able to successfully complete the driving task, suggesting that virtual driving could be a potential complement to driving simulators.

Using mixed reality in vehicles provides a potential alternative to using driving simulators when studying driver-vehicle inter- action. However, virtual reality systems introduce latency in the visual system that may alter driving behavior, which, in turn, results in questionable validity. Previous studies have mainly focused on visual latency as a separate phenomenon. In this work, latency is studied from a task-dependent viewpoint to investigate how participants’ driving behavior changed with increased latency. In this study, the investigation was performed through experiments in which regular drivers were subjected to different levels of visual latency while performing a simple slalom driving task. The drivers’ performances were recorded and evaluated in both lateral and longitudinal directions along with self-assessment questionnaires regarding task performance and difficulty. All participants managed to complete the driving tasks successfully, even under high latency conditions, but were clearly affected by the increased visual latency. The results suggest that drivers compensate for longer latencies by steering more and increasing the safety margins but without reducing their speed.

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.

Even though the realism of driving simulators increases constantly, there is a potential issue with how representative the test is compared to a real life scenario. An alternative to simulators is to present a mixture of real and simulated environment to the driver and perform the scenario at a test track when driving a real vehicle. This enables an efficient way of testing that inherits many of the advantages of driving simulators as well as some of the advantages of physical testing in prototype vehicles. The present paper is a compilation of previous research in augmented reality in vehicle driving situations, focusing on technical limitations of Head-Mounted-Displays.

In this ViP project the focus of investigation was whether drivers more readily accept either rumble strips or an in-vehicle lane departure warning system (LDW) in unintentional lane departure situations. The results show that acceptance was high for both alternatives, but while the drivers showed more satisfaction from using the LDW, they also showed more trust in the rumble strips. Twenty-four drivers drove the VTI driving simulator SIM III in car mode with simulated rumble strips in one drive and with a simulated Volvo LDW in another drive. A forced yaw motion of the vehicle induced the unintentional lane departures. The results showed no choice in favour of the LDW or the rumble strips, but a clear preference for having a function that warns for unintentional lane departure. Several participants thought it was good to have both types of warning in parallel. Although Response completion time was shorter with the rumble strips warning, there was no difference between the warning types, neither in Time to get car back in lane nor in Lane exceedence area. Thus, there were no major overall differences between the LDW and the rumble strips as measured in the present study. The conclusion is that the drivers’ acceptance, as well as performance, was high for both the rumble strips and the LDW. The positive opinion on the need for assistance systems in unintentional lane departure when drivers are directing their visual attention away from the road is thus further strengthened.

Driving simulator studies can reveal relevant and valid aspects of driving behavior, but underestimation of distance and speed can negatively affect the driver's performance, such as in performance of overtaking. One possible explanation for the underestimation of distance and speed is that two-dimensional projection of the visual scene disrupts the monocular-based illusory depth because of conflicting binocular and monocular information of depth. A possible solution might involve the strengthening of the monocular information so that the binocular information becomes less potent.

In the present study, we used an advanced high-fidelity driving simulator to investigate whether adding the visual depth information of motion parallax from head movement affects sense of presence, judgment of distance and speed, and performance measures coupled with overtaking. The simulations included two types of driving scenario in which one was urban and the other was rural. The main results show no effect of this head-movement produced motion parallax on sense of presence, head movement, time to collision, distance judgment, or speed judgment.

However, the results show an effect on lateral positioning. When initiating the overtaking maneuver there is a lateral positioning farther away from the road center as effect of the motion parallax in both types of scenario, which can be interpreted as indicating use of naturally occurring information that change behavior at overtaking. Nevertheless, only showing tendencies of effects, absent is any clear additional impact of this motion parallax in the simulated driving.

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.

The VTI simulator IV (Sim IV) is the fourth advanced driving simulator designed and built at The Swedish National Road and Transport Research Institute (VTI). The simulator, taken into operation 2011, has an 8 degrees of freedom (DoF) moving base, a field of view (FoV) of 180 degrees and features a system for rapid cabin exchange. With a budget of roughly 2,4 M euro; Sim IV was developed to provide VTI’s newly established Gothenburg office with advanced driving simulation capability, and to be a cost efficient complement to the Sim II and Sim III facilities in VTI’s Linköping office. This paper describes the design and technical performance of the facility. A brief summary of results and experience from validation studies for the first three years of operation is also presented.

This publication presents a project aiming to develop virtual representations of real roads for use in driving simulators. The development was done in order to enable assessments of new systems on existing and well known roads in a driving simulator, and will increase the external validity of virtual testing. Furthermore, the usage of the virtual model of such roads makes the simulator results better comparable to earlier performed or later following road tests. The roads connecting Göteborg-Borås-Alingsås-Göteborg were selected. The purpose for this is due to their proximity to the vehicle industry in west Sweden and to the test tracks “Hällered” and “AstaZero”. However, the tools and methods developed can be used to build a virtual representation of any other road through a surrounding landscape and/or more urban environment. The project was carried out in steps, starting with data collection (investigation and assessment of available data from different sources as well as measurement of road properties) followed by data treatment (remove irrelevant data and errors, filtering, etc.), modelling (mathematical description of road properties) and simulation (selection of data formats for real time simulation).

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.