Investigations of Cell Phone Use While Driving in NC
Jane StuttsWilliam HunterHerman Huang
University of North CarolinaHighway Safety Research Center
Project Tasks:
• Statewide telephone survey of cell phone users and non-users.
• Analysis of characteristics of cell phone-related motor vehicle crashes.
• Supplemental data collection by NC State Highway Patrol.
Statewide Telephone Survey Goals
• Obtain updated information on cell phone use and user characteristics.
• Compare cell phone users to non-users.
• Obtain opinions of users and non-users on issues of cell phone safety and regulation.
• Obtain baseline measures for future comparisons.
Telephone Survey Conclusions
• 3 in 5 drivers have used a cell phone while driving.
• Usage highest in 25-39 and 40-54 age groups, and does not differ by gender or race.
• Average talk time decreases with age, and is higher for males than females.
• 1 in 4 users have a hands-free device, but not all use it.
Survey Conclusions (cont.)
• Users perceive talking on phones to be less distracting and less of a safety concern than non-users.
• Users less likely to support legislation that would prohibit anything other than hand-held phone use.
• Users less likely to support stricter penalties for cell phone drivers in crashes.
Identification and Analysis of Cell Phone Crashes
• Computerized search of NC crash report narratives from January 1996 through August 2000
• Search words: answer, carphone, cell, dial
• Narratives read to determine their relevance
• 452 cell phone crashes identified
– 0.04% of all crashes (an underestimate)
– Increased from 0.01% in 1996 to 0.15% in 2000
Sample Narratives
• Driver 1 bent down to answer car phone and ran into back of Veh. 2 which knocked Veh. 2 into rear of Veh. 3.
• Driver 1 stated that he ran off the roadway while trying to reach for his cell phone.
• (Not used) Driver 1 stated that she had just got out of the eye doctors office and her pupils were dialated and she ran the red light.
Data Limitations
• Search terms may have missed some narratives.
• Drivers may not admit they were using a cell phone.
• Officers may not ask about cell phone use.
• Extent of underreporting is not known.
• Hand-held vs. hands-free is not known.
Crash Severity for Cell Phone Users vs. Non-users
0
20
40
60
80
100
User Non-User
K Fatal
A Serious
B Moderate
C Minor
0 No Injury
Urban vs. Rural Crashes for Cell Phone Users vs. Non-users
0
20
40
60
80
100
User Non-User
Rural
Urban
Gender of Cell Phone Users vs. Non-users in Crashes
0
20
40
60
80
100
User Non-User
Female
Male
Age of Cell Phone Users vs. Non-users in Crashes
0
5
10
15
20
25
16 17 18-24 25-34 35-44 45-54 55-64 65-74 75+
UserNon-user
Time of Day of Cell Phone vs. Non Cell Phone Crashes
0
5
10
15
20
25
30
35
6AM -10AM
10AM -2PM
2PM - 6PM
6PM -10PM
10PM -2AM
2AM - 6AM
Cell Phone
Non Cell Phone
Road Class for Cell Phone vs. Non Cell Phone Crashes
0
10
20
30
40
50
60
70
Cell Phone
Non Cell Phone
Vehicle Type for Cell Phone Users vs. Non-users
0
10
20
30
40
50
60
70
Pass.Car
Pickup SUV Van/Minivan
SingleUnit
Truck
TractorTrailer
Other
User
Non-user
Violations for Crash-involved Cell Phone Users vs. Non-users
0
10
20
30
40
50
60
User
Non-user
Summary of Findings• Cell phone crashes more likely to occur:
– On local roads and in urban areas
– During mid-day or early afternoon hours
• Drivers involved in cell phone related crashes are more likely to be:– Ages 35-55
– Male
– Driving sport utility vehicles
– Cited for failure to reduce speed or traffic signal violations
Special Data Collection by NC State Highway Patrol
• All 8 NC SHP districts participating
• Two month data collection period, May 15 - July 14, 2002.
Supplemental Data Collection Form“Complete this form for any crash where a cell phone was in use.”
• What type of cell phone was the driver using? (hand-held, hand-held with headset, etc.)
• What was the driver doing at the time of the crash? (talking, dialing, answering, etc.)
• How important was the cell phone in causing the crash? (very, somewhat, not at all, uncertain)
• How did you obtain information about cell phone use in this crash? (observed, driver volunteered, questioned driver, witness report, etc.)
• Estimated 11.8% of cell phone crashes statewide reported by NC HP.
1,475 projected crashes annually
Descriptive Results
• 29 cell phone crashes statewide over the 2-month data collection period
– Only 1 hands-free phone
– Predominantly occurred while talking on phone (9 crashes), followed by reaching for phone (5 crashes), dialing (4 crashes) and answering phone (3 crashes)
– 86% very significant, 14% somewhat significant in causing crash
– Information most often volunteered by driver, but officers also questioned driver.
Cell Phone Crash Projections
• 29 cell phone crashes statewide over a 2-month period
Translates to 174 crashes annually
• But only 11.8% of cell phone crashes statewide reported by NC SHP.
1,475 projected crashes annually
Full report can be accessed at:
http://www.hsrc.unc.edu/
Thank You!
Survey Methods
• Random digit dial household telephone survey.
• Adults ages 18+, NC resident, valid driver’s license.
• Targeted 500 users, 150 non-users.
• At least 50 respondents in each of following age groups: 18-24, 25-39, 40-54, 55-69, 70+.
• Descriptive tabulations and multivariate regression analysis using SAS.
Screener Results
• Residency, age, driver license checks, plus
“Do you talk on a cell phone while driving?”
• 1006 completions, 106 non-completions (90.5% of all contacts)
• 550/1006 cell phone users (54.7%)
Percent Using Cell Phone While Driving by Age
Adjusted % using cell phone while driving: 58.8%
0
10
20
30
40
50
60
70
80
18-24 25-39 40-54 55-69 70+
Age Distribution of Cell Phone Users vs. Non-users
0 20 40 60 80 100
Non-user
User18-24
25-39
40-54
55-69
70+
Gender Distribution of Cell Phone Users vs. Non-users
0 20 40 60 80 100
Non-user
User
Male
Female
Vehicle Type Distribution of Cell Phone Users vs. Non-users
0 20 40 60 80 100
Non-user
UserCar
Pickup
SUV
Van/Mini
Other
Cell Phone Use Characteristics- Type of Hands Free System
No Hands-free72%
Hands-free 28% Headset 64% Speaker phone 33% Other 3%
Outgoing & Incoming Calls per Day by User Age
01
02
03
04
05
06
0
18-24 25-39 40-54 55-69 70+
Age
Pe
rce
nt
3+ Outgoing
3+ Incoming
Outgoing & Incoming Calls per Day by User Gender
01
02
03
04
0
Males Females
Age
Pe
rce
nt
3+ Outgoing
3+ Incoming
Opinions on Cell Phone Legislation(Percent who would vote to support)
0
10
20
30
40
50
60
70
80
90
100
Hand-held phonesillegal
Any type phoneillegal
Stricter sanctionsfor drivers in
crashes
Per
cen
t
UserNon-User
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