Police reports undercount cellphone use before crashes by factor of at least 7, IIHS study finds
Telematics data from safe-driving apps show police reports miss most cellphone use in the 30 seconds before crashes, undercounting it by a factor of at least 7.
- 7
- 7%
- 8%
- 17,000
What Happened
A new IIHS study drawing on telematics data from safe-driving apps confirms that police reports dramatically undercount cellphone use in the moments before crashes. Telematics showed drivers used their phones in 7% of single-vehicle crashes and 8% of two-vehicle crashes within 30 seconds before impact, while police reports recorded cellphone use in less than 1% of those same crashes. That means police reports undercount cellphone use by a factor of at least 7.
“It's widely accepted that police reports often fail to capture the role of cellphones in crashes. Many smartphone functions are hard for a witness to see, and drivers are reluctant to admit being distracted. Telematics are allowing us to understand the true magnitude of the problem.”
Researchers linked crashes recorded by safe-driving apps on the Cambridge Mobile Telematics (CMT) platform to police-reported crashes in four states from 2021 to 2024, matching events that occurred within the same 15-minute window and one-mile radius. That produced a sample of nearly 17,000 linked crashes. The platform tracks hand-held calls, hands-free calls, device manipulation, and passive use such as an unlocked screen during navigation or video. Police reports noted almost none of this activity.
- Manipulation: 590; Passive use: 534; Hands-free calls: 87; Hand-held calls: 19
- Manipulation: 17; Passive use: 15; Hands-free calls: 1; Hand-held calls: 6
Anything that takes a driver's focus away from the road—including eating, talking, or daydreaming—increases crash risk, and looking away for just two seconds doubles the risk of a crash or near-crash. The rise of screen-based apps like gaming and social media makes this especially worrisome. In many jurisdictions, laws have yet to catch up. To address modern smartphone uses, 21 states now prohibit drivers from holding phones, laws that IIHS research finds are more effective than bans on specific behaviors. In a separate IIHS survey, nearly 25% of drivers admitted to watching a video while driving at least once in the previous 30 days.
“The apps may be new, but the danger isn't. Any phone use that takes a driver's eyes off the road can increase crash risk.”
Police reports and telematics data agreed on the type of cellphone use in only 3 out of nearly 17,000 linked crashes. Police officers may not always be able to determine exactly how a driver was using a cellphone after a crash, and in many jurisdictions only certain types of cellphone use are illegal. If legal behaviors go unreported, lawmakers may be slow to realize that they also increase crash risk. The study says telematics data could help address that disconnect.
Why this matters
Police reports are a primary record of crash causes for lawmakers and safety officials. This study shows the real scale of cellphone distraction is at least seven times larger than official records suggest, meaning laws and public awareness may be lagging far behind the actual risk. It also shows even legal phone uses like navigation can be dangerous when drivers take their eyes off the road.
Terms in This Story
- telematics
- Technology that monitors vehicle movement and driver behavior, often using smartphone sensors, to record events like crashes and phone use.
- passive cellphone use
- When a phone's screen is unlocked but the driver is not touching it, such as with navigation or a playing video.
- hands-free calls
- Phone calls made without holding the phone, such as through a vehicle's Bluetooth system.
- hand-held calls
- Phone calls made while physically holding the phone.
Summarised from the linked release; details can be imperfect — always verify against the original source.