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SAE International Launches Recommended Practice J2944 for Operational Definitions of Driving Performance Measures and Statistics

WARRENDALE, Pa., July 8, 2015 -

SAE International has published SAE Recommended Practice J2944, Operational Definitions of Driving Performance Measures and Statistics.

SAE J2944 is a foundational document providing driving performance operational definitions for on-road vehicles operated by a driver, automatically driven (self-driving), or operated by shared control.


It is based on other foundational documents such as the AASHTO Green Book, the Highway Capacity Manual, and the Manual of Uniform Traffic Control Devices, and is supplemented with more than 300 references. 


“This Recommended Practice was written to advance global mobility, which is SAE International’s core mission,” said Paul Green, the lead author of this standard. “Progress in science and engineering depends upon having a common language for exchanging ideas, be it the metric system, or this recommended practice.”


The measures and statistics defined in this document are used to describe the lateral and longitudinal control of road vehicles as part of safety and/or usability evaluations of (1) driver distraction caused by in-vehicle information systems (e.g., navigation systems, in-vehicle cell phones), (2) driver awareness and assistance systems (e.g., adaptive cruise control, lane keeping assistance, collision warning, crash avoidance braking), (3) fitness to drive/licensing, (4) drug and medication use by drivers, (5) autonomous driving, and (6) for other purposes. These measures and statistics appear in technical standards, journal articles, proceedings papers, technical reports, and presentations.


J2944 defines more than 80 terms related to driving, such as lane departure, gap and headway. The definitions enable researchers and OEMs to avoid misleading, inconsistent or confusing use.


 “To encourage use, we not only provided the definitions, but also guidance in their use, key studies that have used them, and representative data,” Green said. “Although use of this recommended practice will be required in many contexts, our goal was to make this document so useful and easy to use that people would want to use it anyway.”


SAE International is a global association committed to being the ultimate knowledge source for the engineering profession. By uniting over 137,000 engineers and technical experts, we drive knowledge and expertise across a broad spectrum of industries. We act on two priorities: encouraging a lifetime of learning for mobility engineering professionals and setting the standards for industry engineering. We strive for a better world through the work of our philanthropic SAE Foundation, including programs like A World in Motion® and the Collegiate Design Series™.


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