Motorists

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Motorists Perceptions of Aggressive Driving A
Comparative Analysis of Ontario and California
Drivers

• David L. Wiesenthal
• Christine M. Wickens
• York University
• Kathy Rippey
• Ontario Provincial Police

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Aggressive Driving Statistics

• Ontario Provincial Police (OPP) received up to
  500 telephone calls per week complaining about
  aggressive driving behaviour (Mitchell, 1997).
• 38 of Ontario drivers reported experiencing some
  form of abuse over the past year (Toljagic,
  2000).
• 90 of American Automobile Association members
  reported witnessing an aggressive driving
  incident in the last year (National Conference of
  State Legislatures, 2000).

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Aggressive Driving Statistics

• In 2002, 88 of Canadian drivers admitted to
  engaging in aggressive driving behaviour within
  the past year (Nerves of Steel Study, 2002).
• 65 of Canadians considered driver aggression to
  be a serious or extremely serious problem.
  Ontarians were the most concerned Canadian
  drivers (Traffic Injury Research Foundation,
  2001).
• Estimates indicated that aggressive driving
  contributed to 28,000 highway deaths per year in
  the USA (Road Rage, 1997)

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Previous Research(Sarkar, Martineau, Emami,
Khatib, Wallace, 2000)

• Data
• 1987 cell phone calls reporting unsafe driving to
  the California Highway Patrol in San Diego County
  in April, June, and September of 1998
• Coding Scheme
• Speeding
• Speeding plus some other behaviour
• Weaving and Cutting
• Tailgating
• Road Rage (rude language/gestures, horn
  honking, preventing others from passing)

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Previous Research(Sarkar, Martineau, Emami,
Khatib, Wallace, 2000)
Categorization of Cell Phone Calls N 1987
SPEEDING OTHER BEHAVIOUR 25
ROAD RAGE 13
SPEEDING 20
WEAVING CUTTING 27
TAILGATING 13
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Previous Research(Sarkar, Martineau, Emami,
Khatib, Wallace, 2000)

• Results Time of Year
• After combining all three categories of
  aggressive driving, no differences were found
  between June and September.
• No seasonal variation was found for speeding.
• There was a significant difference in the number
  of reported road rage incidents between June and
  September. The authors did not report which month
  received the greatest number of reported
  incidents.

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Previous Research(Sarkar, Martineau, Emami,
Khatib, Wallace, 2000)

• Results Day of Week
• The number of calls varied by day of the week for
  all incidents together and each category.
• Friday received the greatest number of calls, and
  Sunday received the lowest.
• Results Time of Day
• The time period when aggressive driving,
  speeding, and road rage were reported most was
  1500 to 1800 hours.

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Previous Research(Sarkar, Martineau, Emami,
Khatib, Wallace, 2000)

• Weaknesses
• The use of combination classifications (e.g.
  speeding some other behaviour) is imprecise. It
  doesnt indicate how many calls involve weaving,
  tailgating, etc.
• The classification system makes unwarranted
  assumptions about driver intentions (e.g. Forced
  vehicle off road may have resulted from vehicle
  inattention rather than road rage.)
• Very minor incidents were included in the road
  rage category, giving a very distorted view of
  driving violence (e.g. horn honking, preventing
  others from passing)
• Absence of coding scheme reliability statistic.

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OPP Data

• At various times throughout the year, the OPP
  engages in well-publicized aggressive driving
  enforcement campaigns
• Motorists were encouraged to pull off to the side
  of the highway, and to call in and report
  aggressive drivers
• 14,406 telephone calls concerning driving
  complaints were made to the OPP Call Centre in
  the year 2000

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Coding Scheme

• A) Improper Speed - (i) Speeding/Racing
• (ii) Unnecessary Slow Driving
• (iii) Sporadic Speeds
• B)Tailgating
• C) Dangerous Lane Changes/Lane Usage
• D) Improperly Equipped and Unsafe Vehicle
• E) Disobedience of Traffic Signs and Signals
• F) Hostile Driver Displays
• G) Erratic Driver
• H) Driver Inattention
• I) Hazardous Road Conditions Not Attributable to
  Driver Behaviour
• J) Cannot be Classified
• Each call could be placed in any one or more
  categories.

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Coding Scheme Example

• Possibly impaired, weaving, nearly forced me off
  the road, no headlights.
• Coded as
• Erratic driver
• Dangerous land changes and lane usage
• Improperly equipped and unsafe vehicle

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Reliability of the Coding Scheme

• Each month of calls was coded by two independent
  raters one graduate student and one
  undergraduate student.
• If there was a disagreement between the two
  primary coders, a third independent coder
  categorized the call. The final classification
  included categories selected by at least two of
  the three coders.
• Reliability of coding system using Cohens kappa
  .84

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Driver Complaints to the OPPN14406
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What is Erratic Driving? N3024
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Monthly Complaints to the OPP N14406
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Daily Complaints to the OPPN14406
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Time of Complaints to the OPPN14406
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Conclusions

• Type of Driving Behaviour Reported
• The most commonly reported aggressive driving
  behaviours are 1) dangerous lane usage
• 2) excessive speeding
• When we drive, we need to feel that other
  drivers behaviour is predictable. When drivers
  are speeding or weaving, their behaviour is seen
  as unpredictable and sufficiently disconcerting
  to warrant reporting to the police.

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Conclusions

• Time of Year
• The number of driving complaints to the OPP rises
  during the summer months, coinciding with the
  rise in traffic volumes due to increased tourism
  and vacationers.
• Day of the Week
• The greatest number of complaints was reported on
  Fridays. This result replicates the findings of
  Sarkar et al. (2000).
• The lowest number of complaints was reported on
  Mondays. However, for several of the individual
  categories, the lowest number of complaints was
  reported on Sundays, as was found by Sarkar et
  al.

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Conclusions

• Time of Day
• As seen in the Sarkar et al. research (2000), the
  current study indicated that most complaints were
  made between 1200 and 1800 hours.
• Like Sarkar et al., dangerous lane usage was
  reported most often between 1500 and 1800 hours.
• Unlike Sarkar et al., however, speeding and
  tailgating were reported more frequently between
  1200 and 1500 hours.

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Conclusions

• Increased traffic congestion is related to the
  number of reported incidents of aggressive
  driving behaviour. This is consistent with the
  findings of Hennessy Wiesenthal (1997, 1999),
  who found evidence for congestion-induced stress
  leading to aggressive roadway behaviours.

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Potential Applications

• Simplified data recording for the OPP
• Identification of appropriate targets and time
  periods for future OPP enforcement campaigns
• Focus of media campaigns, advertisements, and
  warning signs
• Themes for driver education and testing