Distracted Driving: Do Laws Work?

By October 17, 2016Blog

In late August, the National Safety Council (a non-profit organization chartered by the U.S. Congress) released alarming estimates of the number of traffic fatalities during the first half of 2016. They estimate that 19,100 people were killed on U.S. roads during this period, nearly 18% higher than the first half of 2014. The estimated number of serious road injuries during this time? About 2.2 million people. Crashes, injuries, and fatalities have been increasing in recent years.

Last year saw the largest number of American traffic fatalities since 2008, and at this rate, we may exceed 40,000 annual fatalities for the first time in many years. This bad news comes to us even in the face of many impressive recent advances in safety features in cars.

So why is this happening? There are two important factors at play. First, the amount of driving has increased over the past few years due to a stronger economy, increasing employment rates, and lower gas prices. Second, the amount of distracted driving caused by smartphones has increased. (Pokemon Go is the most recent culprit, but this trend has been happening due to everything else we do on our smartphones like texting, social networking, email, and yes, even navigation to find directions.)

Don’t we have laws to penalize phone use while driving? Indeed, many states have significant penalties for texting while driving, and fourteen states in the US treat all handheld phone use as a “primary violation”.

How well do these laws prevent distracted driving? To answer this question, we analyzed data gathered from over 16,000 users over four months of 2016 from CMT’s DriveWell program. The program measures driving quality using data gathered from sensors on a smartphone, applying machine learning and signal processing algorithms on sensor data to score driving quality. One of the key factors we measure is phone distraction. As noted in our prior blog article, DriveWell’s phone distraction score penalizes only significant handheld distractions, such as picking up a phone and talking, or using any app by moving the phone and tapping on it. It does not penalize mounted use or hands-free use. The goal is to identify and dissuade significant distractions that likely take the driver’s eye off the road, rather than penalize things like hands-free calling, which are problems because of their cognitive impact, but still not as harmful as the behaviors that take both the mind and the eye off the road. Thus, if the app flags distracted driving, it almost certainly is.

The Results

In our data set, we found that there is only a modest correlation between states that have strong penalties against all handheld phone use, and the average number of minutes spent distracted per 100 miles of driving.

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Distracted Driving - v3
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Distracted Driving (Overlay)

The summary of our findings is that the average number of minutes of significantly distracted driving per 100 miles of driving was:

  • For states with laws against all handheld use (14 states): 3.17 minutes
  • For states with laws against all handheld use for “under 18” drivers (11 states): 3.25 minutes (including Arkansas, which penalizes phone use for drivers under 20
  • For states with laws against handheld use only for learners (4 states): 3.57 minutes
  • For states with no laws against any handheld use (20 states): 3.82 minutes (but dropping to 3.47 minutes when we exclude South Dakota, whose users had 10.4 minute of distracted driving in our data set)
  • This adds up to 49 states; that’s because, as in many other things, New Hampshire is unusual — laws there fine the driver for phone use if an accident occurred, but not otherwise. In NH, we see 2.8 minutes of distracted driving per 100 miles — lower than the national average of 3.7 minutes.

These findings indicate that these laws only modestly dissuade handheld distraction. We know of no recent similar studies, except for a report seven years ago from the Highway Loss Data Institute using crash data from New York, DC, California, and Connecticut. This report concluded that: “Month-to-month fluctuations in rates of collision claims in jurisdictions with bans didn’t change from before to after the laws were enacted. Nor did the patterns change in comparison with trends in jurisdictions that didn’t have such laws.”

When are drivers distracted by their phone?

American drivers are significantly distracted by their phone on nearly 31% percent of all drives. Moreover, 29% of all distractions — a large proportion — occur at a dangerously high driving speed of over 56 mph (90 kmph).

In over 11 percent of the drives, we found that the driver was significantly distracted by their phone for over 60 seconds while driving in a moving vehicle. The two pictures below, as the saying goes, are worth a couple thousand words.

So what can we do about this problem?

Carrots or sticks? Laws against distracted driving are like sticks. They are required, but this data, and the increasing number of crashes, injuries, and fatalities show that an alternative approach, involving carrots — i.e., positive behavioral incentives — is well worth trying.

A recently posted article showed how drivers respond positively to the DriveWell program and its incentive structure. These results are extremely promising — reducing distracted driving by 35% across all drivers within 30 days, and even more across the better drivers — and suggest a compelling way to dramatically reduce the scourge of distracted driving.