Global Technical Regulation for Quiet Road Transport Vehicles Informal Group | Session 4 | 16-18 Jul 2013
Washington, DC
Agenda Item 6.
Consideration and review of the key technical elements for the draft GTR

Following is brief summary of the documents presented. They are available for review online at the UNECE GTR IWG work site. (https://www2.unece.org/wiki/display/trans/GTR+for+QRTV+-+4th+session)

-Presentation by JASIC – Japan Suggestions for AVAS Sound Requirements – Part 2 Measurement in Real-World Conditions

In follow-up to study data reported in the 3rd QRTV GGTR IWG meeting, JASIC presented “real-world” test results that support adoption of sound requirements that contain at least 2 distinct 1/3 active bands. This data verifies that there is a proportional relationship between audible distance and overall sound pressure. Therefore, this report concludes the volume of the approaching sound should be determined by the required audible distance.

-Presentation by JASIC – Proposal for the AVAS Requirements

JASIC presented a summary of their studies on forward and reversing sound requirements. Assuming a background sound level of 55 dBA, and stopping distances of 5m @ 10 km/h and 11m @ 20 km/h, the recommendation is:

OA Sound Level1/3 Octave Band Level
Forward at 10 km/h5043
Forward at 20 km/h5648
Reversing47not required

-Presentation by ISOISO 16254 / SAE J 2889-1 Development Status
A review of actions and conclusions since the last QRTV IWG meeting was given:

-ISO WG42 meeting was held in Warsaw to review issues identified in ballot
comments as well as issues identified in SAE comments to NHTSA NPRM.

-A SAE/ISO meeting was held to review testing work conducted for the purpose of
evaluating the draft text for technical accuracy, practicability, and clarity.

-Testing indicates both overall SPL and 1/3 octave results can be measured and reported with sufficient precision.

-Proper treatment of modulated signals remains as an outstanding topic.

-Pitch shift can be measured and reported with sufficient precision.
-Using the maximum in each 1/3 octave band, and the overall SPL, as the basis for determining if a test facility is acceptable is a practical and feasible specification.

-Narrowband measurement indoors with simulated vehicle speed provides means to accurately and precisely identify frequency shift.

Planned future work includes:
  -July-September 2013: Continuing technical evaluations
  -October 2013: ISO WG42 meeting to evaluate draft text (China).
  -In 2014
    -Continue technical work as identified: Resolution of any identified technical issues.
    -Incorporation of any comments from QRTV IWG or GRB regarding fitness for purpose.
    -Expect ISO DIS document submitted for ballot in 2014.

-Presentation by UTAC (France) – France Proposal for AVAS Requirements

UTAC presented recommendations including:

–Establish the Detectability of EV (with or without AVAS) based on being at least equivalent to ICE vehicles. Therefore, a minimum threshold level for AVAS could be deduced from “low noise” ICE. Also, the sound level to be generated by the AVAS should not exceed the approximate sound level of a similar vehicle of the same category equipped with an internal combustion engine and operating under the same conditions. The maximum sound level is to prevent noise annoyance in quiet urban areas, and to avoid excessive vehicle noise which might mask other important “environmental” sounds. Also, as ICE sound levels are reduced, EV sound levels should not become louder than corresponding ICE vehicles.

-Do not require sound emission in stationary condition, or consider it as an alternative (stationary or start-up/just starting).

-Consider a minimum deactivation speed sound (20 km/h) and a maximum deactivation speed (around 30 km/h). This allows manufacturers the ability to adapt speed deactivation between these two thresholds.

-Consider at least one tone in the “low frequency” range (below 800Hz) and one tone in the “high frequency” range (above 1.25kHz).

-Supports exclusion of sounds as proposed in R.E. 3.

-Pitch shifting shall be at least 8% / 10 km/h.

-Presentation by Brigade – Brussels Demonstration

As requested at the Dec. 2012 QRTV IWG meeting, Brigade constructed a demonstration of their AVAS technology. The demonstration focused on the location & directivity of the sound while minimizing the environmental impact (noise outside and inside the vehicle). The demonstration testing was conducted using existing, readily available components, not specifically developed for optimum performance. Due to time constraints the demonstration sound did not include pitch shifting. The demonstration vehicle was shown to achieve the NHTSA NPRM sound performance recommendations.

-Presentation by IDIADA (Juan Garcia) – Electric Vehicle Alert for Detection and Emergency Response (eVADER)

A summary of the eVADER project was presented. The primary objective of this work is to improve pedestrian safety without increasing the noise pollution generated by electrified vehicles. The project’s background, organization, objectives, partners, and timing was briefly reviewed. A summary of the concept definition, sound psychoacoustics, method for generating the warning sound, and implementation of into a demonstration vehicle was discussed.

Documentation
GTRQRTV-04-03 ISO/SAE QRTV status as of 13 July 2013 (ISO)
GTRQRTV-04-04 Brigade report on the demonstration of its bbs white sound alarm system (Brigade)
GTRQRTV-04-05 eVADER: Specific safety issues of electric vehicles (eVADER, EARPA, and IDIADA)
GTRQRTV-04-06 Japan suggestions for AVAS sound requirements: Part 2- Measurements in real-world conditions (JASIC)
GTRQRTV-04-07 French proposals for AVAS requirements (France)