ISA in California: Weighing Safety Benefits Against Public Concerns

Speeding is a leading contributor to roadway fatalities in the United States, and California consistently ranks among states with the highest number of speed-related crashes—including second in the nation (after Texas) in 2023. Intelligent Speed Assistance (ISA) technology has emerged as a solution aimed at mitigating this issue by notifying drivers of speed limits (through auditory, visual, or haptic feedback) and, in some cases, intervening and lowering the speed to the posted speed limit through pedal resistance, temporary deceleration, and power limitations (although the latter is not widespread). New Mineta Transportation Institute (MTI) research, A Holistic Inquiry of Intelligent Speed-Assist Technology: Safety Impacts, Technology Implementation, and Challenges, presents a comprehensive investigation into ISA system safety benefits, implementation challenges, and public perception, with a focus on California drivers. 

This study’s multi-method approach, which included a large-scale quantitative analysis of over two million consumer complaints and nearly 300,000 recall records from the National Highway Traffic Safety Administration (NHTSA), found that:

• Keyword analysis of NHTSA consumers revealed that issues related to speed control and ISA functionality were among the most reported, with the most frequently occurring terms being “speed” (71,631 mentions), “engine” (28,923 mentions), and “brake” (27,499 mentions), suggesting widespread user concerns around unintended acceleration, loss of control, and inadequate responses to driver input. 

• Among 286 surveyed California drivers, over half recognized the potential safety benefits of ISA, but 55%  were also concerned about loss of control, 53% about system malfunction, and 37% about privacy.

• Survey results indicated that 62% of respondents believed ISA would reduce their speeding behavior.

• Drivers showed a strong preference for advisory or supportive ISA systems that provide feedback without taking full control of vehicle speed. (Only 2% of respondents preferred “intervening” ISA; the remaining 98% preferred supportive and advisory options.

“Public trust in ISA systems hinges on transparent, ethical data practices,” explain the study’s authors. “Nearly 80% of survey respondents reported at least some concern over data privacy. To remedy this, systems should avoid real-time transmissions of identifiable data unless anonymized and consent-based. Strong governance structures  and accessible reports indicating what data is being collected and how it is used are also important.”

Overall, the findings suggest that ISA systems could effectively reduce speeding and enhance safety, but their success depends on thoughtful design, public trust, and supportive policy frameworks. Public outreach campaigns that help the public understand what ISA is and how it works will be a critical part of moving forward. Sharing information about the benefits of ISA and how private data is protected during its use will build public trust and facilitate implementation.

Overall, as California and other states explore broader implementation, aligning driver preferences, technological capabilities, and regulatory structures will be crucial to realizing ISA’s full safety potential.

ABOUT THE MINETA TRANSPORTATION INSTITUTE

At the Mineta Transportation Institute (MTI) at San Jose State University (SJSU) our mission is to increase mobility for all by improving the safety, efficiency, accessibility, and convenience of our nations’ transportation system. Through research, education, workforce development and technology transfer, we help create a connected world. Founded in 1991, MTI is a university transportation center funded by the US Department of Transportation, the California Department of Transportation, and public and private grants, including those made available by the Road Repair and Accountability Act of 2017 (SB1). MTI is affiliated with SJSU’s Lucas College and Graduate School of Business.

ABOUT THE PRINCIPAL INVESTIGATOR

Dr. Sahar Ghanipoor Machiani is an Associate Professor of San Diego State University with expertise in traffic safety, driver behavior modeling, automated vehicles, and infrastructure-based safety systems. Nusheen Baradaran is a graduate student in Civil Engineering at San Diego State University. Her research focuses on intelligent vehicle technologies and transportation system safety. Dr. Arash Jahangiri is an Associate Professor of San Diego State University with expertise in data mining techniques, statistical analysis, machine learning algorithms, and traffic safety.

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