1 Introduction
2 Methodology
2.1 Aims
2.2 Test permit
“
AutomatFahrV”
, defines basic conditions for testing automated vehicles on public roads in Austria [3]. The regulation allows for test drivers under certain conditions to transfer driving tasks to assistance systems or automated driving systems. This applies to systems which have already been approved and are in series (for example a jam assistant), but are currently not allowed to be used due to existing drivers’ obligations. On the other hand, the regulation allows testing of completely new systems at research and development stage, not complying with existing regulations. As outlined below, Section 2, §7 of AutomatFahrV defines certain rules for testing self-driving shuttles on public roads (excerpt):-
For the purposes of this regulation, a self-driving shuttle is a vehicle of categories M1, M2 and M3 equipped with a system capable of handling all driving tasks at a speed up to 20 km/h.
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This system may be tested by vehicle manufacturers, system developers and research institutes.
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The system may only be used on public roads with mixed traffic if at least 1000 test kilometres have been previously covered by the system.
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The self-driving shuttle may be tested on a predefined test route only.
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As soon as the driver activates the system, all driving tasks are transferred to the machine. In this case, the system must be able to handle all driving situations automatically.
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The vehicle must offer an emergency button to deactivate the system at any time. If a critical situation arises, the driver must immediately press the emergency button.
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The system may be tested up to a maximum speed of 20 km/h.
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During the test period, persons may only be transported on the intended seats and not on a commercial basis.
2.3 Test setup
2.4 Test drives
2.5 Test vehicle
3 Results and discussion
3.1 Statistical data
3.2 Test experiences
3.2.1 Deployment
3.2.2 Positioning
3.2.3 Automated driving capabilities
Observed behaviour | Possible reason | Applied solution | Occurrence |
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Shuttle stopped for obstacle | • Parking vehicles on the roadside or at bus stops | • Bypassing the obstacle manually • Setting the shuttle to automatic mode after the obstacle | • Frequent |
Shuttle stopped for no apparent reason | • Branches of trees or shrubs on the roadside • Wrongly detected obstacle • Unreliable positioning • Sensor reflections due to water lacquers, heavy rain or snowfall | • Setting the shuttle to automatic mode again for continuing the test drive • If this was not successful, driving back manually to a safe parking position (e.g. bus stop) | • Frequent |
Detection of other road users failed | • Velocities > 30 km/h of approaching or passing vehicles at left turns or exits from bus stops or side roads • Dead angles of 360° LIDAR sensors due to vehicle’s own shading • Low spatial resolution of the Velodyne VLP-16 LIDAR sensors | • Stopping the shuttle and taking over manual control | • Frequent |
Unclear interaction with other road users | • Planned safety stops • Stopping without any reason • Is overtaking safe? • Abandoned priority • Missing trust by other road users | • Variable messages on the back screen of the vehicle • Using hand signs if possible | • Frequent |
Shuttle could not be set to automatic mode after a stop | • Vehicle being out of driving path • Software problem | • Driving manually to the next safe parking position (e.g. bus stop) • Applying one or several restarts • Contacting the Navya supervision team for solving the problem via remote control | • Several test drives |
3.2.4 Interaction with other road users
3.3 Passenger feedback
4 Conclusions
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Standardised and (partly) automated processes for digitising the driving environment: The current practice of proprietary and mostly manual setup of the digital driving environment has to be improved. Standardised tool chains for the digital modelling of the environment have to be established very soon.
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Systematic testing of driving scenarios: A systematic testing of driving scenarios especially with the respect to varying driving environments for autonomous shuttles is missing so far. Most of the testing consists of trial and error. A standardised and integrated process from simulation to system tests to closed test environments and open road testing including feedback loops on each stage is necessary.
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Testing on public roads: Since first regulations for testing of autonomous vehicles have passed legislations in European countries, these should be used to include public road testing in the research and development process (integrated with the previously mentioned process). However, public road testing should be accomplished following well-defined and transparent test procedures and results fostering improved learning for all involved stakeholders (e.g. vehicle manufacturers, technology providers, public transport companies and associations, public authorities). This transparent process should also include publication of test results.
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Role of digital infrastructure: Until now, we have only poor experiences which role digital infrastructure (3G/4G/5G networks, ITS-enabled traffic lights, vehicle-to-infrastructure communication,) can or should play in the context of automated vehicles. In future trials we should put more attention on how the vehicle should/could interact with such an infrastructure for improved reliability.
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Realistic environmental conditions: Most of the current tests are conducted in city centres at sunny weather conditions (also the majority of our test drives was at sunny weather). However, regular operation of automated shuttles also means operation during the winter season or on rainy days. Other aspects are rural areas or steepness of the route. Further testing has to pay more attention to such aspects.
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Interaction with other road users: Interaction with other road users has turned out to be one of the most challenging issues during public road testing. While research of the last years has predominately focused on the role of human drivers in the context of automated vehicles, the aspect of how other road users interact with automated vehicles has widely been neglected. In mixed traffic, a lot of traffic situations occur which cannot be adequately solved without human interaction. From our experiences, this topic is one of the key issues for safe and reliable operation and has to be immediately addressed.
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Passenger safety: Until now, there is little knowledge how passengers feel during driverless operation. Results from our trial as well as from others indicate that passengers feel safe with an operator on board [5]. However, how does this feeling change in driverless operation? Which kind of passenger interaction do we need for reaching the same or higher levels of trust in comparison to driver-operated buses?
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Design of automated mobility systems: In the future, we should pay attention to how automated vehicles can fit seamlessly into an existing (public) transport system or how we have to change these systems in order to cope with the new requirements. The test-drives in Koppl revealed, that at the current stage of development it is really hard to integrate an autonomous shuttle in existing public transport systems since the technology is by far not major enough. The main feedback from a lead user workshop with transport operators, village representatives and potential passengers was that everybody confirms the huge potential of the technology, but to be of use for daily operation, the technology has to work stable under all possible conditions. Passengers do not mind whether the shuttle is operated in automatic mode or not, they expect a reliable public transport link to their destination. However, currently, there are too many situations, which the shuttle cannot handle automatically and any manual intervention typically leads to service interruptions contradicting the idea of operating the shuttle as a reliable feeder to a major public transport line. Moreover, handling bad weather or winter conditions adequately is also a pre-requisite before going into daily operation. Especially for first/last mile scenarios, several open questions have to be addressed properly. Among others, these questions are how to guarantee smooth interlinking with other public transport lines, how to handle peak times where the demand exceeds the capacity of the shuttle, how to reach similar passenger safety and trust in comparison to driver-operated public transport or how to validate safe and reliable operations of an automated shuttle. As far as technical, legal and social questions are not fully answered, any automated shuttle operation has to be declared as experimental. It is essential that passengers are aware of the experimental stage for having realistic expectations and being aware of further research and development steps.