Evaluation of Arizona’s statewide handheld cellphone ban using roadside observation and telematics data

October 2025

Introduction: The current study assessed whether a statewide ban against drivers holding phones reduces such behavior. In 2019, Arizona passed a statewide prohibition on holding a cellphone while driving. Police could issue written warnings immediately but could only issue citations beginning in 2021. Method: We used a pre–post study with control group design to estimate handheld phone use in Arizona before and after citations were permitted relative to Nevada. The before-citations period was limited to April 2019 through December 2020. Roadside observations of handheld phone use occurred in July 2019 and 2021. Telematics data from Cambridge Mobile Telematics on percentages of trips and trip duration with handheld phone use among drivers using their platform was collected for the same before period and two different post periods, one short-and one long-term (2021 and 2021–2024). Results: Statewide analyses showed consistently lower likelihood of handheld calling in Arizona after citations were permitted, though only the telematics analyses were statistically significant. For example, the telematics data showed that the percentage of trip time with handheld calls decreased 26% by 2024. Roadside observation indicated phone manipulation decreased in Arizona after January 2021 but not significantly. Short-term telematics analysis found small changes in phone manipulation: the percentage of trip time with manipulation decreased, but the percentage of trips with any manipulation increased. The long-term analysis showed that both measures increased by 2024. Average monthly citations written by state troopers declined each year from 2021 to 2024. Conclusion: Handheld calling reductions in Arizona estimated after the law’s effective date were robust and consistent with earlier work. The lack of robust decline in cellphone manipulation may have been influenced by preexisting local ordinances prohibiting phone use in some Arizona jurisdictions or the limited before-citations period. The increase in cellphone manipulation over time is consistent with the decline in enforcement. Practical implications: Long-term increases in manipulation suggest that the temptation to use smartphones is stronger than concerns about receiving a citation, and therefore additional interventions will be required.