An Evidence-Based Assessment
of Crash Risk and the Use of Cell
Phones while Driving
Jim Sayer
Carol Flannagan
Distracted Driving
National Safety Council
NSC estimated that 25% of crashes are caused
by cell phones alone, a model-based estimate
• Assumes that drivers do not self-limit cell-phone use
in any way
• Assumes a simple causal link between cell-phone use
and crashes
Comparisons with drunk driving
Source: National Safety Council (2010). Attributable Risk
Estimate Model. National Safety Council, Itasca, IL.
Evidence-Based Assessments
U.S. DOT’s analysis of several crash
databases shows:
45,230 drivers involved in fatal crashes in 2009†
5,084 (11%) drivers in fatal crashes, are coded
for all forms of distraction combined †
1008 (2.2%) are associated with cell phones in
use or present (GES analysis)
This does not account for contributory factors
† Sources: NHTSA (2009). Distracted Driving 2009. Report
No. DOT HS-811-379
Evidence-Based Assessments
NMVCCS internal sources of distraction:
The most frequently coded factor was
conversing with a passenger (16%)
• “As a word of caution, conversing with a passenger as
an associated factor in a large number of crashes
should not be taken to understand that this factor
actually caused distraction so frequently. NMVCCS
data merely indicates the presence of this factor in
many crashes…..”
Source: NHTSA (2010). Distracted Driving and Driver,
Roadway, and Environmental Factors, DOT HS 811 380
Evidence-Based Assessments
NMVCCS Internal sources of distraction:
Phone use was an associated factor in 3.4
percent of the crashes (conversing on phone,
dialing or hanging up phone, and text
messaging)
Source: NHTSA (2010). Distracted Driving and Driver,
Roadway, and Environmental Factors, DOT HS 811 380
Evidence-Based Assessments
NOPUS data shows cell phone use held
constant, at about 7%, from 2005 – 2008 †
Total crashes involving all distractions held
constant, at about 17%, from 2006 – 2009‡
† Source: NHTSA (2010). Distracted Driving and Driver,
Roadway, and Environmental Factors, DOT HS 811 380
‡ Source: NHTSA (2009). Distracted Driving 2009. Report No.
DOT HS-811-379
The Paradox of Cell Phone Use
and Crashes Rates
Cell phone use rates while driving are
holding steady
Distraction related crashes are holding
steady
Overall, not just when driving, cell phone
use is increasing
Does this suggest a form of self-regulation
by drivers?
The Paradox of Cell Phone Bans
and Crash/Use Rates
Cell-phone bans, without immense
enforcement, have not been very effective
in changing crash rates
IIHS recently reported no change in
insurance claims for crashes in
jurisdictions that instituted hand-held cell
phone bans, nor any change in
comparison jurisdictions
Source: Status Report, Special issue: phoning while driving
(February, 2010). Insurance Institute for Highway Safety
The Elephants in the Room
In 2008: 37,261 fatalities
11,773 people (32% of all fatalities) were killed in
alcohol-impaired-driving crashes
11,674 lives (31% of all fatalities) were lost in
speeding-related crashes
8,500 lives (23% of all fatalities) were 16 – 24 yrs
5,290 lives (14% of all fatalities) were
motorcyclists – 37 times more likely to die
Source: NHTSA (2009). Traffic Safety Facts 2008 Data. Report
No. DOT HS-811-162
What Does it All Mean?
Is distracted driving an issue?
YES, it is 11% of fatal crashes
Is the root of all distracted driving cell
phones?
NO, cell phones are a small percentage
Are cell phones any worse than many
other forms of distraction?
This is still the subject of MUCH debate
What Does it All Mean?
Is driving while using a cell phone like
driving drunk?
ABSOLUTELY NOT, a damaging comparison
Potential to trivialize drunk driving
Still Lots of Work to be Done
Still several issues related to distraction,
in general, that are not understood:
What role does self-regulation play?
Is cell phone distraction unique?
What are the actual risks associated with all
forms of distraction?
What technological solutions are there?
What are the long term effects of legislation?
What are use rates?
• NOPUS is may be over estimating cell phone use
Thank You
jimsayer@umich.edu
Distracted Driving
Secretary LaHood:
“Last year, 5,500 people were killed as a result
of distracted driving”
“Look, the epidemic in America is caused by
the fact that everybody has a cell phone or a
BlackBerry and people think they can use
them anytime, anyplace.”
Source: NPR Talk of the Nation, October 26, 2010