SAE International is a global association of more than 128,000 engineers and related technical experts in the aerospace, automotive and commercial-vehicle industries. Read More

MEDIA ADVISORY/BACKGROUNDER: Subject: SAE Vehicle Sound for Pedestrians (VSP) Subcommittee

WARRENDALE, Pa., April 9, 2008 -


In the spring of 2007, SAE International was approached by the National Federation of the Blind (NFB) regarding a concern about visually-impaired pedestrians involved in traffic incidents with hybrid vehicles. The concern focused on the quiet operation of hybrid vehicles at low speeds. 

Based on the NFB’s request, SAE International Motor Vehicle Council asked the Hybrid Electric Vehicle (HEV) Technical Committee to study this concern. The HEV technical committee concluded that this concern did merit more study, but recognized that it required different expertise than the members of that committee could provide.

The responsibility for this issue was then transferred to the SAE Safety & Human Factors Committee, which formed the Vehicle Sound for Pedestrians (VSP) subcommittee at its November 2007 meeting. The VSP subcommittee was formed and has met monthly in 2008.  This subcommittee is made up of stakeholders from several different backgrounds and organizations including: representatives of the blind community, government agencies, academics and automakers.

Current Status:

The VSP subcommittee created three Task Forces to gather technical information to assist in determining the technical issues:

  • Audience for the Specification (who is the targeted beneficiary
  • Target sound level and type of sound (what types of sounds are necessary to achieve the desired effect, and what types of sound will achieve the desired effect with the least undesirable and unintended consequences)
  • Driving Conditions for the sound (what combination of vehicle conditions, vehicle status, and ambient conditions are required)

These Task Forces meet independently and report back at the monthly subcommittee meetings.

The VSP subcommittee is first working to accurately define this issue. While working to define the issues, the subcommittee also is working to understand the conditions where these types of incidents are likely to occur (example: alley and street intersections; at stop lights, etc.) As these factors are better understood, the subcommittee will propose and evaluate different methods and/or countermeasures to address the issues.

Even though the subcommittee’s initial focus is only on hybrid vehicles, any data collected or generated in understanding the issues could eventually include other vehicle types besides hybrids.

By following a systematic approach to this concern, using the “best available” information, understanding the incident problem by identifying the underlying conditions and/or scenarios, while cooperating with stakeholders from different backgrounds and points of view; we believe this subcommittee is well positioned to address the technical concerns quickly -- as long as data can support the issue(s) and the most promising subset of countermeasures can be identified.

We recognize that any output from this subcommittee must both address the issues, and minimize the creation of new concerns, unintended consequences, or burden on others.

The VSP subcommittee plans to issue a technical report or recommended practice by the end of 2008 based on its analysis of pedestrian safety issues related to the quiet operation of hybrid vehicles and its identification and evaluation of potential countermeasures to address these issues.  By involving a diverse mix of experts and stakeholders and gathering available data or researching new areas as needed, this group is addressing the pedestrian safety concerns associated with hybrid vehicles in a technically sound and responsible manner.