Tag Archive: THOR

  1. Adaptive acoustic vehicle alerting system (AVAS) – what will help improve acoustic ecology?

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    LEVA-EU Member Thor Avas shares the latest insight on acoustic technology as increasing numbers of electric vehicles appear on the roads and sidewalks.

    Electric transport has a positive effect on the ecology of the city and agglomerations in the broadest sense of the word.

    When considering electric vehicles locally, the emission of exhaust gases is reduced, and the acoustic ecology is improved by reducing the noise of vehicles (the hum of internal combustion engines disappears). Micromobility vehicles increase the personal mobility of the population.
    However, with the spread of electric transport, new difficulties also appear – the number of collisions with pedestrians is increasing. This is not only due to the fact that electric transport can pick up speed faster, but also because it is quiet and has low acoustic visibility at low speeds. Electric vehicles are even classified as silent vehicles, which, according to the national legislation of various countries in North America, Europe, and Asia, must be equipped with a special acoustic device that makes sounds when driving – an AVAS system (acoustic vehicle alerting system).

    Requirements for AVAS systems are regulated by national and international regulations FMVSS 141, GB7258, EU 540/2014, UN R138.01.
    These documents also define the maximum sound level (75 dBA) emitted by the AVAS system.

    The visibility of an AVAS-equipped vehicle to a pedestrian will be determined not only by vehicle characteristics, travel speed, road surface types, AVAS sound types, and loudness but also by the acoustic characteristics of the environment.
    When considering AVAS systems, the visibility of an electric car in a noisy city can be sufficient, but in a park area or countryside, it could be excessive. In this case, the damage to acoustic ecology can be even greater than the noise of an internal combustion engine.

    Thor AVAS conducted an experiment that assessed the visibility of vehicles (a car with an internal combustion engine, and an electric car with the AVAS system on and off) on a quiet country road.
    Visibility was determined using the “fixation time” – the time from the moment a research expert acoustically recorded (heard) that a car was moving in their direction until the moment the car reached them. Passages of an electric vehicle with the AVAS system turned on had two volume options – with the AVAS system operating with a sound level of 75 dBA (maximum allowed) and a sound level of 69 dBA (twice as quiet).

    The results showed that operating at acceptable volume levels, the AVAS system in the countryside will provide excessive visibility, that is, pedestrians will hear the approach of an electric car for 25-55 seconds at a speed of 10 km/h and 25-30 seconds at a speed of 20 km/h. These visibility values are several times higher than those for a conventional ICE vehicle.
    None of the regulatory documents indicates the possibility of an adaptive mode of operation of the AVAS system – such a mode in which the volume of operation is selected based on the acoustic environment. Such a mode of operation could reduce the noise impact on the environment and improve the acoustic environmental friendliness of the AVAS system.

  2. THOR AVAS launches pedestrian safety survey

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    LEVA-EU member THOR AVAS conducts research to improve road and pedestrian safety. The recently launched survey takes no more than 5 minutes and will aid in deepening the understanding of acoustic safety in relation to LEVs.

    Access the survey, here.

    “Please join us and together we will understand how to make the environment more comfortable and safer.” – THOR AVAS

  3. Thor AVAS conducts comprehensive electric vehicle traffic safety study on ‘acoustic visibility’

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    The problems of acoustic ecology in the human environment are studied by many researchers around the world, especially the contributions to city noise made by cars. In recent years, more and more electric vehicles that are much quieter have appeared on city streets. Cars and motorcycles are traditionally powered by the rather noisy operation of an internal combustion engine. Electric transport, on the other hand, runs on electric motors powered by noiseless energy sources (batteries, fuel cells, capacitors, etc.). As a result, the electric car creates noise only due to the contact of the tires with the asphalt and due to the turbulent air currents on the car body. All this makes the movement of electric vehicles less noisy and, at low speeds, almost silent. Therefore, electric vehicles are classified by UN Regulation No. 138 as silent vehicles. With the undoubted benefit of this circumstance for the acoustic ecology of the city, there is also a quiet threat to humans – a pedestrian may simply not hear the approach of an electric car. It is for this reason that the legislation of many countries of the world obliges electric vehicles to be equipped with special sound devices – AVAS systems that increase the acoustic visibility of electric vehicles.

    Contribute to the latest Thor AVAS survey on pedestrian safety, here.

    In recent years, a wide variety of micromobile vehicles have also begun to appear on the roads in large volumes. And, more importantly, on the sidewalks of cities – scooters, gyro scooters, unicycles, segways and everything that, despite its harmless appearance, can sneak up unnoticed (at a speed of up to 30 km/h) to an unsuspecting pedestrian. While the issue of ensuring the safe movement of microtransport vehicles causes great discussion, no country in the world has resolved this in law.

    Thor AVAS, together with the Research Institute of Building Physics, is conducting a large scientific study of the safety of electric transport. Their work studies how different vehicles are acoustically visible (heard) to a pedestrian and how it is possible to increase their visibility without causing ecological damage to the acoustic environment.

    In-laboratory work takes place in a unique acoustic measuring complex – a large acoustic anechoic chamber. This is a room in which there is absolutely no echo due to the walls and ceiling being covered in a layer of a special sound-absorbing structure more than 1 meter thick.

    The room used by Thor AVAS is the largest anechoic chamber in Europe and one of the largest chambers in the world – the floor area exceeds 120 square meters. It is also very quiet in this chamber – so quiet that it is a unique auditory experience, with the background noise level in the chamber only reaching 18 dBA.

    During testing, many loudspeakers are placed in a circle around the cell. Together they make up the radiating part of the laboratory setup. Six speakers imitate the noise of the environment, reproducing, for example, the sounds of a city courtyard or a city park, in 5.1 stereo, comparable to a movie theater. Another three-way speaker system simulates the noise of an approaching electric vehicle’s tires.

    The approach of a car is simulated at a speed range between 10 and 50 km/h. Imitation occurs by increasing tire volume according to auditory laws. When the distance between the car and the pedestrian decreases, the sound pressure level increases by 6 dB.

    Finally, consider the last loudspeaker is the AVAS system, the principle which is the subject of the study. By playing different sounds through the AVAS system, traffic safety conditions can be significantly improved.

    The essence of the experiment is to determine how long it takes a pedestrian to hear a car approaching them. Participants of the experiment are given registration panels and the experiment begins. At first, participants in the experiment hear only the sounds of the environment, the park or the yard, because the simulated car is still “far away”. At the moment when participants hear the approaching car, they press the registration button on their remotes. By this pressing, it can be determine how long it took for the pedestrian to register the approaching car, i.e. how much time the pedestrian has to react to the approach and decide on further actions. For example, an electric car without an AVAS system is heard when impact time is between 3-5 seconds, depending on the vehicle’s speed. In such a short time, the pedestrian will not have time to react to the approach of the vehicle and a collision may occur.

    When driving an electric vehicle with the AVAS system turned on, it is possible to significantly increase the time for acoustic detection of an approaching car by a pedestrian. The most effective method is to turn the system up to high volume. Very loud and unpleasant sounds can be played through the AVAS system (or alternatively, turn on loud music) and the residents of the next few blocks will know in advance about the approach of the car, which, of course, will have nothing to do with traffic safety. The correct sound of AVAS should ensure the safe movement of an electric vehicle and sound at such a volume that it will not exceed the established rules and sanitary standards for a residential area. However, sounds of the same loudness can have varying visibility. By changing the timbre of the sound, its frequency range, and introducing volume modulations and discrete components at certain frequencies, it is possible to significantly increase a vehicle’s visibility without increasing the volume.

    The Thor AVAS study aims to find the best ways to control the visibility of an electric vehicle using the AVAS system. The goal is to create such sounds for the AVAS system which, on the one hand, will not be unpleasant, excessively loud, and attract unnecessary attention, and, on the other hand, provide optimal and speed-independent visibility.

    Anechoic chamber tests of THOR AVAS – YouTube

  4. First acoustic tests of the conspicuousness of an electric car with the THOR AVAS system carried out in Russia

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    Electric transport does not have a motor, making it is practically inaudible when driving, and it is hardly noticeable, which increases the likelihood of collisions with other road users.

    According to European 138 UN Regulations, such vehicles must be equipped with a special sound warning system – AVAS, the task of which is to increase the visibility of silent electric vehicles.

    Since the law was passed back in 2016, and the electric transport industry is developing rapidly, the solution in the form of AVAS (Acoustic Vehicle Alerting System), which provides for the inclusion of warning sounds at speeds from 0 to 20 km / h, is also not entirely relevant. The latest Tesla accelerates from 0 to 100 km / h in 3 seconds. Which can lead to serious consequences on the roads.

    Car Systems company (THOR), a resident of Skolkovo that produces the unique THOR AVAS sound notification system is also scrupulously studying all aspects, conducting its research with electric vehicles, taking into account various data on loudness and sounds created by the company’s sound engineers, taking into account various scenarios.

    In October 2021, the THOR AVAS division conducted the first open road tests in Russia at the Skolkovo innovation center with the support of WATTS BATTERY, which provided portable power supplies for connecting acoustic equipment. And of course, the Dewesoft Base Station, a mixed-signal acquisition system and multichannel data logger in one device, helped the engineering team make such accurate measurements.

    The essence of the study was to assess the conspicuousness of an electric car with the THOR AVAS system: the test participants (experts) took a specially designated place near the roadway, the car began to move 500 meters away from them and, at the moment when the experts began to hear the car, they pressed a button on the remote control. t the same time, the equipment recorded the distance from the car to the experts (according to GPS coordinates), the acoustic conditions next to the experts, and the speed of the car.

    The work of acoustic engineers at THOR presents the results of an experiment evaluating the subjective indicators of a car’s conspicuousness by pedestrians (listeners), which were determined through the distance to the car at the moment the expert fixed its approach, and the time from the moment of fixation to the car’s approach to the expert.

    These subjective indicators of conspicuousness were compared with the objective parameters of the noise from the car measured according to UN Regulation No. 138 – the level of sound pressure, its frequency response, as well as the sound level.

    The electric Tesla Model 3 with the THOR AVAS system drove at five speed modes of 10, 20, 30, 40, and 50 km / h with three positions of the AVAS volume control – 60% (corresponds to the maximum permissible sound level according to UN Regulation No. 138), volume 30% and with the AVAS system turned off. For comparison, 2 cars with an internal combustion engine (ICE) were taken.   

    At low speeds of 10 and 20 km / h, the noise from a car with an internal combustion engine is greater than from an electric car, which can be seen from the results of measurements of the maximum sound pressure level LZmax (Pic. 1.b). The Tesla is with turned off of AVAS system.

    The qualitative fact that electric cars are less noticeable to pedestrians than conventional cars with internal combustion engines (ICE) is well known from our everyday experience.

    According to the results of our experiment, we were able to express this visibility already quantitatively – we determined the time of fixation by pedestrians of an electric car and a car with an ICE (i.e. the time that passes from the moment when the pedestrian noticed the car to the moment when the car drove up to the pedestrian). For an electric car, this time is approximately 10 seconds, and for a car with an internal combustion engine – 15 seconds. The results of acoustic measurements showed that this is due to the noise of the ICE  in the low-frequency region, which is determined by the second harmonic of the fundamental tone of the engine operation.

    An experiment to estimate the fixation time for an electric car with an AVAS system operating at maximum volume (according to UN Regulation No. 138) showed that an electric car is noticed by a pedestrian in a suburban environment for too long a time – 25-45 seconds. Moreover, with an increase in speed, this time decreases.

    An ideal AVAS system should work in such a way that the fixation time does not depend on the speed of the electric vehicle (at least at speeds up to 40 km / h), or on the level of environmental noise, and at the same time does not exceed the fixation time of cars with ICE. That is, the AVAS system should be intelligent and be able to adapt to the environment, which is not provided for by the existing international regulatory documents, and more flexibly adjust to the speed of movement.

    A scientific approach to the development of the sounds of the AVAS system will make it more noticeable at a lower volume, which will have a beneficial effect on the acoustic ecology and reduce the noise level of cities.

    The problem of low conspicuousness applies not only to electric cars but also to lighter vehicles with electric propulsion: scooters, mopeds, motor scooters, and the rest of the so-called micro-transport, which is not defined as a vehicle at all in regulatory documents.

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