National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Driver Perception of Just Noticeable Differences of Automotive Signal Lamp Intensities.

PB95206306

Publication Date	1994
Personal Author	Huey, R.; Dekker, D.; Lyons, R.
Page Count	48
Abstract	The National Highway Traffic Safety Administration (NHTSA) often receives petitions for determination of inconsequential non-compliance from manufacturers regarding vehicle lamp intensities which fall just outside the performance limits as specified in Federal Motor Vehicle Safety Standard 108. They assert that most drivers could not notice the difference, and thus the non-compliance is inconsequential. Typically, a non-compliance regarding intensity has been deemed inconsequential to safety when the performance has been less than 25% above or below the boundary limit. This study empirically evaluated the just-noticeable difference (JND) of several signal lamp types under typical ambient illumination and viewing distance conditions to provide an objective basis for assessing waiver requests. The procedure involved a paired comparison of standard light sources filtered to simulate color and intensity differences. Based on the findings, a difference of up to 25% from FMVSSS 108 intensity requirements appears to be a reasonable criterion for use in decisions regarding the inconsequentiality of non-compliant signal lamps.
Keywords	Signal lamps Visual perception Driver characteristics Test methods Safety Stimulus(Psychophysiology)
Source Agency	Highway Traffic Safety
NTIS Subject Category	85D - Transportation Safety 85H - Road Transportation
Corporate Authors	COMSIS Corp., Silver Spring, MD.; National Highway Traffic Safety Administration, Washington, DC.
Supplemental Notes	Sponsored by National Highway Traffic Safety Administration, Washington, DC.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199513
Contract Number	DTNH22-92-D-07002

Driver Perception of Just Noticeable Differences of Automotive Signal Lamp Intensities.

Driver Perception of Just Noticeable Differences of Automotive Signal Lamp Intensities.
PB95206306

Publication Date	1994
Personal Author	Huey, R.; Dekker, D.; Lyons, R.
Page Count	48
Abstract	The National Highway Traffic Safety Administration (NHTSA) often receives petitions for determination of inconsequential non-compliance from manufacturers regarding vehicle lamp intensities which fall just outside the performance limits as specified in Federal Motor Vehicle Safety Standard 108. They assert that most drivers could not notice the difference, and thus the non-compliance is inconsequential. Typically, a non-compliance regarding intensity has been deemed inconsequential to safety when the performance has been less than 25% above or below the boundary limit. This study empirically evaluated the just-noticeable difference (JND) of several signal lamp types under typical ambient illumination and viewing distance conditions to provide an objective basis for assessing waiver requests. The procedure involved a paired comparison of standard light sources filtered to simulate color and intensity differences. Based on the findings, a difference of up to 25% from FMVSSS 108 intensity requirements appears to be a reasonable criterion for use in decisions regarding the inconsequentiality of non-compliant signal lamps.
Keywords	Signal lamps Visual perception Driver characteristics Test methods Safety Stimulus(Psychophysiology)
Source Agency	Highway Traffic Safety
NTIS Subject Category	85D - Transportation Safety 85H - Road Transportation
Corporate Authors	COMSIS Corp., Silver Spring, MD.; National Highway Traffic Safety Administration, Washington, DC.
Supplemental Notes	Sponsored by National Highway Traffic Safety Administration, Washington, DC.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199513
Contract Number	DTNH22-92-D-07002