eVADER-project.eu - Tasks and objectives

List of Topics:
  1. WP 1 Concept definition and system requirements
  2. WP 2 Psycho-acoustic principles Warning signals Characteristics Threshold definition
  3. WP 3 Warning signal generators
  4. WP 4 Algorithms and strategy definitions for acoustic warning devices
  5. WP 5 Design and construction of acoustic warning devices
  6. WP 6 Vehicle implementation
  7. WP 7 Validation
  8. WP 8 Demonstration
  9. WP 9 Technical management
  10. WP 10 Administrative management
  11. WP 11 Dissemination

WP 1: Concept definition and system requirements

WP Leader: Renault

Overall goal
WP1 aims to define the scope of the study in terms of at-risk situations for pedestrians, of situations where quiet vehicles improve the resident’s comfort, of reduction of the overall noise level in cities, of safety management between the vehicle or driver and the pedestrian and of technical and economical requirements.


  • To investigate and characterize the at-risk situations for pedestrians
  • To investigate and characterize different soundscapes to define psychoacoustic maskers
  • To investigate and characterize different living situations for residents related to comfort perception (linked to silence). Thus, with these 3 specifications, WP1 will propose specific scenarios for the overall project (listening tests for psychoacoustics, activation and deactivation of smart system … )
  • To propose a measurement protocol in order to evaluate the gain of the different systems for the driver, the pedestrian and the residents
  • To define the safety management between driver, car and pedestrian
  • To define the specifications in order to implement the different technologies in vehicle

Technical approach and selected results

First of all, the ambient noise level in five European cities was measured in order to have European representative data of an urban environment. Two types of sites were chosen by partners: one for the “low traffic volume with a moderate noise level” situation (representing a quiet suburban area) and another one that accommodates a “moderate traffic volume with a noise level comparable to a city center”. These recordings are used in the other work packages to define jury tests under laboratory conditions.

An example of measured spectra is shown in figure 1-1. It can be noticed that the spectra of the various sounds show the same trends with differences in levels that define the overall SPL. The noise range between the quiet and noisy streets is about 30 dB(A).

Figure 1-1. Comparison of noise spectra for ambient urban noise for the three measurement points in Barcelona, Spain (IDIADA).

As a second step, the mandatory characteristics of external sounds, that may be applied to Electric Vehicles for the purpose of alerting pedestrians of the vehicles presence, were analyzed. Moreover, the test conditions for a psychoacoustic listening test based on potential risk scenarios were defined as an exemplary judgment protocol. The questions proposed strongly depend on the objectives of the listening test defined in detail with the whole project Consortium.

Several studies were carried out concerning the concepts related to the safety management between driver, vehicle and pedestrian. Statistical studies selected the highest risk accident scenarios, and also evaluated the reduction of the number of accidents due to the presence of the alerting warning sound. The following scenarios were considered:

    1) Vehicle turning  (Near)
    2) Vehicle turning  (Away)
    3) Walking along & Backing vehicle (Near)
    4) Walking along & Backing vehicle (Away)
    5) Waiting to cross

As an example, the vehicle turning scenario is shown in figure 1-2:

Figure 1-2. Vehicle turning – I (Near), Vehicle speed: 10, 20, 30 km/h

To support this research, the exterior noise detected by a pedestrian in a close to accident scenarios was quantified in the proving ground of IDIADA in eight common accident scenarios.

Finally, an overview was made of all practical and legislation constraints related to the design, vehicle installation and usage of Vehicle alert Sound systems.

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WP 2: Psycho-acoustic principles Warning signals Characteristics Threshold definition

WP Leader: INSA Lyon


Overall goal

The goal of this work package is to define the timbre of warning sounds which will be used in the project.


The objective of the task is to develop soundsthat warn a pedestrian that a car is approaching, without creating noise annoyance.  Noise is already a major annoyance factor in cities, and one benefit of electric and hybrid vehicles is to reduce this noise. Therefore, a good compromise between warning sounds efficiency and their contribution to annoyance must be reached. The requirements for a good alert signal are hence that it should be:

  • well detected (also in case of pedestrians suffering from ageing hearing loss).
  • clearly interpreted as indicating a danger.
  • localised (to indicate the direction of the danger.
  • but not too loud nor annoying for the other pedestrians or street inhabitants.

Technical approach and selected results

The definition of the warning signals will be obtained through listening test experiments conducted by several partners.

The work package is organised in four tasks:

  • Task 1 consists in a literature review about warning sounds and alert signals.
  • Task 2 is devoted to detection of warning sounds. Several candidate sounds are used and experiments are conducted by different project partners, enabling the use of a large number of participants. Some listeners are visually-impaired.
  • Task 3 deals withthe meaning of the signals. Alert sounds should have a clear meaning, i.e. they should indicate a danger and, if this is possible without any prior learning, the importance of this danger. Furthermore, itis investigated whether it is possible to give to the pedestrian some information about the speed of the car through the sound. This could be very helpful to visually-impaired pedestrian.
  • Finally, in task 4, the influence of most useful warning sounds on annoyance of a traffic flow will be measured.Alert sounds should not be too annoying for other people (e.g. other road users or pedestrians who are far away from any danger or city inhabitants).

It is expected that this work package will give some useful recommendations about the timbre of warning sounds. Beside the project, this may contribute to the research aiming at regulating such sounds.
As an example, the results of a study on detectability and localization of additional warning sounds are further discussed. The goal of this experiment was to investigate the contribution of three timbre parameters on the ability of listeners to detect and localize an electric vehicle equipped with an additional warning sound.

Nine warning sounds were synthesized. They had a complex periodic structure with a lowest frequency of 300 Hz, and varied according to three parameters:

  • number of components (3, 6 and 9);
  • frequency modulation of some components (none, sinusoidal kind, saw-tooth kind);
  • amplitude modulation (none, sinusoidal, irregular).

These sounds were modified in order to simulate a moving sound, passing in front of a listener at a constant speed of 20 km/h, from 30 m on a side of the listener to 30 m on the other side. Then they were added to a recording of a real electric car driving at the same speed. It was thus possible to simulate different cars equipped with each warning sound and passing in front of the pedestrian, as shown in figure 1.

Figure 1 : simulated scenario. A car is passing in front of a "waiting-to-cross" pedestrian, at 20 km/h.

The electric vehicle (with no warning sound) was included in the set of stimuli, as well as a Diesel engine car.
These eleven stimuli were presented to listeners through headphones, together with a background noise recorded in a city. Rain noise was added to this background noise, as rain noise increases the difficulty for visually impaired people trying to analyse their sound environment. Eight replications of each stimulus were used, representing vehicles coming either from the left or from the right side of the listener.
The background noise was continuously presented to the listener. At randomly selected time, one of the 88 car sounds appeared. The task of the listener was to detect the car as soon as possible and to identify the arrival direction of the car. He gave his answer by pressing a key of a computer keyboard (one key for each arrival direction).

120 people participated to the experiment. They were aged between 20 and 72 and 36 of them were visually impaired.

The results are presented in figure 2. Data are averaged over the whole panel. Detection times were converted to distance to the pedestrian.

Figure 2 : averaged distance to the pedestrian at the detection. 111, 122 and so on represent additional warning sounds.

This figure shows that, as an example, the Diesel car was detected 15 meters before the electric vehicle. The red area represents the dangerous area: it is assumed that if the pedestrian crosses the road while the car is in the red area, he will be hurt as the driver will not have time enough to stop the car.

On the other hand, some warning sounds helped listeners to detect the electric vehicle as soon as the diesel one (sounds 313 and 133).

The same benefit could be measured for the localization errors (figure 3). Localization seems easier for the electric car with the warning sound ref.313 than for the Diesel car.

Figure 3 : number of errors (sum over the whole panel).

Clearly, the benefit of this warning sound is not due to sound level. Figure 4 represents the maximum A-weighted sound level of each stimulus: the diesel car is much louder than all other vehicles (the difference with EV+sound 313 is about 6 dB(A)).

Figure 4 : peak levels of stimuli

This experiment shown that it is possible to use very efficient warning sounds to help detection of quiet vehicles. These sounds can have a low level: the most efficient signals (133 and 313) have very strong temporal variations, which drew the attention of the participants.

Thus a good compromise between pedestrian safety and environmental noise quality can be reached.

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WP 3: Warning signal generators

WP Leader: TNO


Overall goal:

Conceptual design of an acoustical warning signal generator that will be capable of emitting a directional sound beam in a variable direction.


  • To investigate the physical principles and technical possibilities for the design and construction of (a) warning signal generator(s) that are available to realise the requirements and objectives formulated by Work Package 2.
  • Activities in WP3 focus on the assessment of selected key features of acoustic warning generators based on simplified geometries, simulated beam-forming techniques, and partial experimental validation of components and simulation models with the objective to pinpoint expected performance limitations and critical implementation issues.
  • To rank the different concepts and implementations with respect to the conformity with the requirements.
  • To advise and specify the most suitable concept as input to Work Packages 4 and 5.

Technical approach and selected results:

A state-of-the-art inventory of beam-forming principles, technical implementation methods and suitable transducer types was executed in the first task.

In the second task the investigations were aimed at the comparison of different beam-forming methods and implementations in relation to the requirements formulated in WP 1 and WP 2. The requirements dealt with: the number of transducers, the frequency range, required horizontal directivity and the steering range of the beam.

Based on the results of task 1 the principle of an array with moving coil transducers was selected for further development in view of the required sound power output at low frequencies, the necessity of beam steering and the cost. The beam-forming will be realised by electronic means. Several beam-forming methods were compared regarding beam-width and flexibility by allowing computation of beams within the time constraints of real time steering direction variation. The performance of the beam-forming method for uniform and non-uniform arrays was simulated, taking into account the influence of the ground reflection,The conclusion was that a non-uniform array with a Sound power minimisation beam-steering method would deliver the best overall performance.

The development towards a working prototype of the warning signal generator is based on the application of six moving coil loudspeakers that will be mounted in the vehicle bumper of a NISSAN LEAF. This selection is based on the consideration of reliability offered by proven technology. As a possible future option also the application of vibration transducers (mini shakers) that excite the vehicle bumper is being investigated.

After the selection and development of the basic design of the warning signal generator further implementation questions were studied and the influence of environmental and acoustical boundary conditions on the performance of the signal generator were investigated.
Several development steps were verified by laboratory experiments, which gave further test results of the actual performance of the warning signal generator.The design procedure of the directional sound source was validated in real-time experiments. Beam-forming performance was also simulated for more realistic models from WP5 based on transfer functions for sourcesmounted  in the front bumper of a car. This included the reflecting ground surface, and other factors that may influence the beam-forming performance.
The final result will be a set of essential and optional specifications of the warning signal generator that has to be built and incorporated in the prototype vehicle.

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WP 4: Algorithms and strategy definitions for acoustic warning devices

WP Leader: Continental


Overall goal:

Conceptual design of strategies and algorithms for the interior and exterior acoustic warning systems and the associated Human-Machine-Interface (HMI) and environmental perception system.


The design of effective warning strategies for both the driver and the potentially at-risk pedestrians requires reaching the following objectives

  • Definition of a toolset of available warning operations and strategies
  • Definition of strategies and algorithms for exterior warning systems
  • Definition of strategies and algorithms for interior warning systems including an HMI concept
  • Development of an environmental perception system (EP) capable of distinguishing between vulnerable road users (i.e. Pedestrians, bicycles), this can subsequently trigger the acoustic warning systems as well as providing appropriate driver warning signals

Technical approach and selected results:

As a starting point for the design of the different acoustic warning strategies and algorithms, an inventory was made of the applied technologies and especially the strategies and algorithms for both acoustic and non-acoustic warning of drivers and occupants of road, rail,… vehicles. In this study, both existing commercially available systems and on-going technological developments that are still in a research state were treated.

WP3 has provided conceptual design guidelines for the projective exterior warning system. The full exploitation of this system’s potential for warning at-risk bystanders while minimizing the environmental noise pollution however depends on the availability of suitable control algorithms and strategies to steer the warning system. Apart from the warning systems themselves, key ingredients in this warning system architecture are an effective risk estimator and a suitable HMI concept for piloting the different warning systems.

  • The risk estimator uses the principles of risk diagnostics assessed through the available information provided by obstacle detection systems and any available environmental information to obtain statistical information on the likelihood that the trajectories of the vehicle and any nearby bystander may cross.
  • The Human-Machine-Interaction concept considers various use case and scenario that should be addressed depending on the environmental conditions, the available vehicle information (including the risk estimation) and the driver’sattitude and reactions. To support the design of the HMI concept, an inventory was made of different use cases the system should be able to deal with and novel and innovative Human Machine Interaction design principles were considered including multimodal interfaces mixing different communication modalities, depending on the context and the task to be performed, as well as adaptive interactions.

The interior warning systems themselves are also designed in this task and provide crucial information to the driver while managing complex situations. They should warn the driver and provide clear information about the diagnosed risk, allowing him or her to take appropriate action. In this design, both acoustic and visual warnings are merged to achieve optimal driver alertness and to support his or her decision making. For the acoustic diver warning, the use of the existing vehicle audio system to provide intuitively correct sensational information on the detected threat situation was explored through a simulation-based acoustic configuration analysis approach towards internal warning systems, more specifically, to investigatethe generation of direction feeling on the interior warning sound so as to optimally provide information onthe detected direction of the threat situation (generation of a so-called “phantom source” correlated to the VRU). These simulations which are based on Ray Tracing and binaural auralization have provided inputs regarding optimal speakerconfiguration and control (including optimal use of already available audio systems through pre-filtered acoustic warning signals). The digital filter design process is shown schematically in figure 1.

Figure 1 : Simulation-based interior warning system design.

In on-going next steps in this work package, the strategies and algorithms for the exterior warning system are being developed and tested using road safety simulation software tools. In parallel, the environmental perception system is being developed both in terms of concepts and algorithms.

The outcome of this work package will be a full conceptual system architectural design that can be implemented and tested on one of the eVader test vehicles in work packages 5 and 6.


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WP 5: Design and construction of acoustic warning devices

WP Leader: TU-Darmstadt

Overall goal:

The overall objective of this work package is to build a prototype of an in-vehicle warning device and to design the appropriate software.



In this work package a prototype of both the interior and exterior acoustic warning devices will be designed and constructed.

  • Before starting the actual design, the results obtained in work packages 1 through 4 will be translated into technical system specifications for the final prototype.
  • The first design step will be a simulation based assessment of the exterior warning system’s acoustic performance when it is integrated into the prototype vehicle. This study will also consider the impact of various environmental conditions on the warning performance in support of the final design.
  • Based on this virtual pre-study, the warning systems themselves and the necessary software for a real-time implementation of the proposed control strategies will be designed and build
  • In the final stage of the design, the prototypes will be extensively tested and their performance with respect to the technical specifications will be assessed.

Technical approach and selected results:
Based on the results obtained in work packages 1, 2, 3 and 4, the requirements and specifications (such as sound level and frequency limits, size, expected component life-time etc.) for the different elements that make up the eVader warning system were defined. A database was created to track this information throughout the execution of the eVader project and both the hardware and software architectural requirements were documented in a deliverable report.

As a first step in the design of the exterior warning system, a simulation-based design and sensitivity study was executed in close collaboration with WP3, where the optimal electronic control strategies for the transducers used in this system is studied. To obtain realistic system performance predictions while allowing assessing a large number of design variations, a Finite Element based model of a transducer array of six loudspeakers on the bumper and part of the hood of one of the project test vehicles was developed (see figure 1).

Figure 1 : Finite Element based model of the exterior warning device integrated in the test vehicle bumper.

Based on the obtained noise transfer functions between the six speakers and 21 microphone arrays at different distances from the bumper and height from the ground plane, WP3 studies determined a set of suitable control inputs to the different transducers to obtain optimal beam-forming behavior. A typical resulting spatial acoustic pressure distribution obtained by applying such a control scheme to the numerical model is shown in figure 2.

Figure 2 : Spatial acoustic pressure distribution using optimal beam forming control.

To verify the robustness of the warning generator’s performance, a sensitivity study to quantify the impact of the most critical changes in the acoustic environment in which the signal generator needs to operate was performed:

  • Changes in the environmental temperature and relative humidity
  • Impact of the road surface impedance
  • the influence of nearby scattering objects such as e.g. parked vehicles

Since a number of these parameter studies require a significantly larger problem area to be considered, models based on state-of-the-art Boundary Element approaches were used in this robustness study. Figure 3 shows the impact of two nearby parked cars and a realistic road surface impedance model on the warning generator’s performance.

Figure 3 : Impact of nearby cars and road impedance on warning generator performance.

In the next steps, the results of the simulation-based design study and of work packages 1-4 will be used to design and build a hardware and software prototype for the eVader warning system.

The performance and adherence to the requirements and specifications will be verified by means of an extensive experimental validation campaign.



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WP 6: Vehicle implementation

WP Leader: Nissan


  • To integrate algorithms, sounds and hardware specified and developed in WP5 into Nissan, Renault and PSA vehicle architecture.
  • To evaluate the performance and suitability of the system, both in virtual world simulated tests and in real world physical tests.
  • Creation and evaluation of sounds in line with findings of WP2 that also meet Nissan/Renault/PSA brand image (BI), Customer acceptance and Environmental impact requirements.
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WP 7: Validation


The main objectives of WP7 is to validate the results of eVADER.
In order to achieve these objectives, two test phases with different objectives are presented

  • The objective of this first phase is to provide rough data for analysis of human response and checking the structure of the algorithms (WP4) and equipment.
  • The objective of the second phase is to provide robust data for in-depth analysis of human response and development of detection and warning strategies for close-to-accident situations There is a third test phase implemented in WP8 as a demonstration activity. These results will be also used for the validation.
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WP 8: Demonstration


The main objective of WP8 is to obtain experimental data from EV with prototype systems to analyse the
in-service human response of both VRU and drivers.
In order to achieve these objectives, a real world test phase is defined. This test phase complements the previous test phases in WP8. The objective of the third phase is to implement a larger test period for testing the robustness of these strategies as developed in eVADER and validating them.

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WP 9: Technical management


The main objective of WP9 is to assure project coordination such that eVADER technical objectives are met. In addition to co-ordinating and organising eVADER to assuring and/or establishing communication flow, project follow-up (project progress control and planning) and decision making procedures this implies also several secondary activities:

  • interface with the Commission and eVADER reviewers for technical aspects
  • assure quality and timeliness of eVADER activities
  • assure excellent partner communication to facilitate a successful project
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WP 10: Administrative management


The main objective of WP10 is to assure project coordination and administrative tasks completed correctly.

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WP 11: Dissemination

WP Leader: LMS

To ensure that the potential impact of this project is indeed achieved, a series of dedicated activities is included in the work programme as a separate WP to maximally support the transfer of the results to the concerned stakeholders. The concrete WP objectives include the external dissemination to the scientific and industrial community, enabling transfer, continuation and adoption of the research results into actual use, and the internal dissemination within the partner organisations to start up concrete exploitation in added-value activities. The WP objectives also explicitly include bringing eVADER findings to concerned public authorities (covering the EU) and international policy and regulatory organisations. A key objective is also to inform the broad community of road users, including future drivers of EV as well as vulnerable road users. Specific attention is paid to maximally reaching the communities involved with accessibility (including elderly people, people with disabilities), and with particular emphasis on addressing visually impaired persons.

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