NHTSA Rulemaking Activities for Quiet Vehicles Alert Sound Standard

7th Meeting of the Quiet Road Transport Work Group

Osaka, Japan

QRTV-07-08

Rulemaking Schedule • January 4, 2011 President Obama signs Pedestrian Safety

Enhancement Act requiring NHTSA to issue a standard mandating alerts sounds for quiet vehicles in 36 months

• Summer 2011 NHTSA begins Phase III Quiet Vehicles Research to develop compliance test procedures, performance metrics, and pass/fail criteria

• July 12, 2011 NHTSA published Notice of Intent (NOI) to prepare an Environmental Assessment

• August 11, 2011 comment period for NOI closes• Fall 2011 complete Phase III Research• July 5, 2012 release of proposed Quiet Vehicles Standard in

Notice of Proposed Rulemaking and Environmental Assessment

Rulemaking Alternatives

NHTSA believes that Alternatives 2-5 described in the NOI are all feasible approaches for a pedestrian alert sound regulation

Alternative 2 – Recording of Sounds from Internal Combustion Vehicles

• Compliance would be based on acoustic parameters designed around ICE like sounds

• Sound would be recognizable as a motor vehicle in operation

• Represents low cost option for compliance – manufacturers are not required to develop synthetic sounds

• Current soundscape is unchanged lessening concerns about annoyance caused by multiple sounds with different acoustic profiles

Alternative 3 – Synthesized ICE Equivalent Recording

• Recorded ICE sounds processed by digital signal processor

• Would have fewer spectral components than Alternative 2

• Compliance test would be similar to Alternative 2• Possible that these synthetic sounds could have

enhanced detectability • Sound would be recognizable as a motor vehicle

in operation

Alternative 4 – Synthesized Non-ICE Sounds with ICE Components

• Synthetically created ICE-like sounds with components that enhance detectability

• Compliance test would include acoustic measurement for sound levels

• Recognizability would be determined by jury testing or acoustic measurement

• Greater likelihood that the sound will be recognizable• Potential to offer enhanced detectability• Could prove more acceptable to the public than other

synthetic pedestrian alert sounds

Alternative 5 – Synthesized Non-ICE Sounds Developed to Enhance Detectability

• Characteristics common to these sounds include pitch shifting, prominent harmonics in the 150 Hz to 4000 Hz range and four or more frequencies with an average sound pressure level above 50 dba.

• Compliance test would include acoustic measurement for sound levels

• Recognizability would be determined by jury testing or acoustic measurement

• It is possible that these sounds will offer better detectability than ICE like sounds

• multiple sounds with different acoustic profiles could prove annoying to the public

Requirements of Pedestrian Safety Enhancement Act

• Alert sound must allow pedestrians to be able to discern “vehicle presence, direction, location, and operation” when the vehicle is operating below the crossover speed

• Determine the sound level necessary to allow blind and sighted pedestrians “to reasonably detect a nearby electric or hybrid vehicle operating at or below the cross-over speed”