Speeding and Distracted at the Same Time: A New Study Reveals the Most Dangerous Driver on the Road

The most dangerous driver on the road is not the one who is speeding. It is not the one who is on their phone. It is the one doing both, at the same time.

Research published by the Insurance Institute for Highway Safety, using data from nearly 600,000 real trips taken by drivers across the United States, found that the faster a driver is going over the speed limit, the more likely they are to also be using a handheld cellphone at the same time. Not just slightly more likely. On limited-access highways, every additional 5 miles per hour over the speed limit was associated with a 12% increase in the rate of cellphone manipulation. On roads with speed limits of 70 miles per hour or higher, that relationship was even stronger.

In other words, the most dangerous drivers on our roads are not choosing between speeding and distraction. They are doing both, simultaneously, and the worse the speeding gets, the worse the phone use gets alongside it.

“This research confirms what we see in case after case: dangerous driving does not show up in isolation. It clusters,” said Chad Boyles, partner and attorney at the Law Office of Chain | Cohn | Clark. “And when it does, people get killed.”

The Insurance Institute for Highway Safety partnered with Cambridge Mobile Telematics, a company whose smartphone platform is used by insurance providers to track driving behavior for usage-based insurance policies. The dataset covered 593,454 trips taken between July and October 2024, spread across 46 states and all four U.S. Census regions.

Researchers were able to measure, for each trip, how fast the driver was traveling relative to the posted speed limit and how much time the driver spent manipulating a handheld phone with an unlocked screen. That second measure, phone manipulation, is important to understand: This was not passive phone placement or a hands-free call. This was a driver actively handling their phone with the screen on, in a way the device’s gyroscope could detect as consistent with texting, scrolling, searching, or photographing.

The findings on limited-access roads, the freeways and interstates that carry the highest speeds and the heaviest traffic, were particularly striking. Drivers in the study were speeding during 80%of their free-flow driving time on these roads. The additional finding, that phone use climbed steadily and significantly alongside speeding magnitude, paints a picture of compound recklessness that is hard to dismiss.

On primary and collector roads — the kinds of streets that run through neighborhoods, past schools, and along commercial corridors throughout Bakersfield and Kern County — a similar pattern emerged on higher-speed segments. Roads with 55-mile-per-hour limits saw phone manipulation rates jump 36 percent between the slowest and fastest speeding categories.

The researchers offered two explanations for why speeding and phone use tend to co-occur, and both are worth understanding because both matter in the context of crash liability.

1. The first explanation is environmental. On high-speed limited-access roads, the driving task is in some ways simpler. There are no intersections to navigate, no pedestrians stepping off curbs, no traffic signals to monitor. Some drivers appear to interpret that reduced complexity as an opportunity to multitask, reaching for their phone precisely because the road feels easier. The irony, of course, is that the reduced complexity comes alongside dramatically increased crash forces. A distracted driver who drifts at 45 miles per hour has a different set of consequences than one drifting at 75.
2. The second explanation is dispositional. Some drivers are simply more inclined to take risks, and that inclination expresses itself in multiple behaviors at once. The research is consistent with prior studies showing that drivers who speed also tend to engage in other risky behaviors, including phone use, following too closely, and running late-stage yellow lights. This is not a driver who made one bad decision. This is a driver whose overall approach to operating a vehicle puts everyone around them in danger.

That distinction matters enormously in personal injury cases. When an attorney can demonstrate that a driver was not only distracted but also speeding at the time of a crash, and can connect that combination to a pattern of documented risk-taking behavior, the picture presented to a jury is fundamentally different from a simple inattention claim.

“Proving distraction alone is hard enough,” Boyles said. “Proving that the driver was distracted and speeding, and showing that these were not two separate accidents but one person making a series of reckless choices, that changes the conversation about what happened and who bears responsibility for it.”

Highway 99 runs directly through the heart of Kern County. So does Highway 58 and Highway 178. These are limited-access corridors carrying tens of thousands of vehicles daily, many of them commercial trucks, many of them commuters, and all of them traveling at speeds where a moment of inattention leaves almost no margin for error.

The IIHS study did not break its findings down by region, but the data came from drivers across the country, and there is no reason to believe Kern County drivers behave differently from the national sample. If anything, the long straight stretches of Highway 99 through the Central Valley, with their high posted limits, minimal exits, and monotonous visual environment, may create precisely the conditions the study identified as most likely to produce the speeding-plus-phone combination: a fast road, reduced complexity, and a driver who decides that is a good moment to check a message.

When crashes happen on those roads, the consequences are frequently catastrophic. Highway speeds mean high crash forces. High crash forces mean fatalities and life-altering injuries. And in cases where a driver was both speeding and on their phone, the question of accountability becomes not just important but urgent.

California law treats distracted driving and speeding as separate violations, each carrying its own penalties. But in a civil personal injury case, the combination of the two does something more significant than stack violations. It establishes a pattern of conduct that speaks directly to the degree of a driver’s negligence.

In serious injury and wrongful death cases, evidence that a driver was traveling well over the speed limit while actively manipulating a handheld phone can support arguments for enhanced damages. It shifts the narrative from accident to choice, from misfortune to preventable harm. It gives attorneys the foundation to argue not just that the driver made a mistake, but that the driver’s entire approach to operating their vehicle on a public road that day was reckless.

Documenting that combination requires moving quickly. Cell phone records can be obtained through legal process, but they must be requested before carriers purge data. Event data recorders in vehicles can capture speed in the moments before a crash, but accessing them requires prompt legal action. Witness statements, traffic camera footage, and telematics data from the vehicle itself or from any insurance monitoring app the driver was enrolled in can all contribute to building the full picture.

The IIHS study concluded with a call for combined enforcement, targeting speeding and phone use together rather than separately, particularly on high-speed corridors. The researchers noted that speed cameras, which California has now authorized in work zones, could be adapted to detect phone manipulation as well, creating a dual-enforcement tool that addresses both behaviors simultaneously.

They also noted something that carries weight beyond the enforcement context: countermeasures that increase the perceived complexity of a road, such as design features that require more driver attention, may reduce both speeding and phone use at the same time. The behaviors share a root cause, the driver’s perception that the road does not demand their full attention, and addressing that perception addresses both.

“For the rest of us sharing those roads, the practical message is one that Chain | Cohn | Clark has carried for nearly 100 years of serving Kern County: the driver who hurts you may not have intended to. But intention is not the legal standard,” Boyles said. “The standard is whether they acted with reasonable care. And a driver who is 15 miles per hour over the limit with an unlocked phone in their hand did not.”

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If you or someone you know is injured in an accident at the fault of someone else, or injured on the job no matter whose fault it is, contact the attorneys at Chain | Cohn | Clark by calling (661) 323-4000, or fill out a free consultation form, text, or chat with us at chainlaw.com.