Fact

Distraction - How dangerous is it when drivers are distracted in traffic?

Many distracting activities seem to increase the risk of being involved in a road crash. American Naturalistic Driving studies show that activities causing visual distraction are most dangerous, entering a telephone number for example, reading or writing, typing or reading text messages, but also reaching for objects and prolonged glances to objects outside the car [13] [18]. Table 2 presents the risks (the so-called ‘odds ratios’) and the percentage of time American drivers in the ND study by Dingus et al. [13]. are engaged in (‘prevalence’) all kinds of distracting activities. What is important about this study is that the road crash risk was calculated on the basis of actual road crashes, unlike earlier studies in which near-crashes were also included. Including near-crashes may, however, bias the results (for more information see [7]).

An odds ratio higher than 1 means that an activity involves a higher risk than ‘ordinary’ driving does, whereas an odds ratio lower than 1 points to a lower risk. An odds ratio of 1.4 for the activity ‘talking to passengers’ in Table 2 means that the risk of a road crash is 1.4 times higher than when the driver is not talking to passengers. The odds ratio is an estimate. The confidence interval of 95%, presented in brackets behind the odds ratio, indicates that it is at least 95% certain that the odds ratio of talking to passengers is larger than 1.1 (the first number) and smaller than 1.8 (the second number). A prevalence of 14.58% for the same activity means that drivers talk to passengers for an average of 14.58% of their time behind the wheel.

Activity (not phone-related)

Odds Ratio

(95% confidence interval)

Prevalence

Reacting to children in the rear

0,5 (0,1 – 1,9)

0,80%

Talking to passengers

1,4 (1,1 – 1,8)

14,58%

Eating while driving

1,8 (1,1 – 2,9)

1,90%

Drinking while driving

1,8 (1,0 – 3,3)

1,22%

Dancing and swinging’ in one’s seat

1,0 (0,4 – 2,3)

1,10%

Applying make-up/personal hygiene

1,4 (0,8 – 2,5)

1,69%

Reading and writing (also on tablet, excluding phone)

9,9 (3,6 – 26,9)

0,09%

Extended glance durations to external objects

7,1 (4,8 – 10,4)

0,93%

Reaching for objects (for example in glove box)

9,1 (6,5 – 12,6)

1,08%

Activity with a handheld mobile phone
(not defined whether it was a smartphone):

 

 

Browsing on phone (for example finding a contact, searching the internet)

2,7 (1,5 – 5,1)

0,73%

Dialing

12,2 (5,6 – 26,4)

0,14%

Reaching for phone

4,8 (2,7 – 8,4)

0,58%

Typing, sending and reading (’texting on whatsapp’)

6,1 (4,5 – 8,2)

1,91%

Conducting a phone conversation

2,2 (1,6 -3,1)

3,24%

All activities with a handheld phone together

3,6 (2,9 – 4,5)

6,40%

Table 2. The odds ratios and prevalences of some of the activities distracting drivers [13].

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