Motorists’ Perceptions of Aggressive Driving: A Comparative Analysis of Ontario and California...

Motorists’ Perceptions of Motorists’ Perceptions of Aggressive Driving: Aggressive Driving:

A Comparative Analysis of A Comparative Analysis of Ontario and California DriversOntario and California Drivers

David L. WiesenthalChristine M. Wickens

York University

Kathy Rippey

Ontario Provincial Police

Aggressive Driving StatisticsAggressive 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).

Aggressive Driving StatisticsAggressive 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)

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

• DataData• 1987 cell phone calls reporting unsafe driving to the California

Highway Patrol in San Diego County in April, June, and September of 1998

• Coding SchemeCoding Scheme• Speeding • Speeding plus some other behaviour• Weaving and Cutting• Tailgating• “Road Rage” (rude language/gestures, horn honking, preventing

others from passing)


Categorization of Cell Phone Calls N = 1987

SPEEDING & OTHER BEHAVIOUR

25%

WEAVING & CUTTING

27%

TAILGATING13%

SPEEDING20%

ROAD RAGE13%


• Results – Time of YearResults – 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.


• Results – Day of WeekResults – 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 DayResults – Time of Day• The time period when aggressive driving, speeding, and road rage

were reported most was 1500 to 1800 hours.


• WeaknessesWeaknesses• The use of combination classifications (e.g. speeding + some other

behaviour) is imprecise. It doesn’t 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.

OPP DataOPP 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

Coding SchemeCoding 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.

Coding Scheme ExampleCoding 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

Reliability of the Reliability of the Coding SchemeCoding 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 Cohen’s kappa = .84

Driver Complaints to the OPPDriver Complaints to the OPPN=14406N=14406

8976

5551

34332533

897 630 227 204 202 135 131 515

010002000300040005000600070008000900010000

Frequency

What is Erratic Driving?What is Erratic Driving? N=3024N=3024

2355

1052

704

229 16228 62 25 15 2 1

0

500

1000

1500

2000

2500

Frequency

Monthly Complaints to the OPPMonthly Complaints to the OPP N=14406N=14406

738 736

984 967

13201411

1633

1830

1596

1316

1044

831

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Frequency

Daily Complaints to the OPPDaily Complaints to the OPPN=14406N=14406

19011721

18832049

2134

2549

2169

0

500

1000

1500

2000

2500

3000

Sun Mon Tues Wed Thurs Fri Sat

Frequency

Time of Complaints to the OPPTime of Complaints to the OPPN=14406N=14406

710

341

1263

2104

2717

3070

2532

1669

0

500

1000

1500

2000

2500

3000

3500

Frequency

ConclusionsConclusions

• Type of Driving Behaviour ReportedType 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.

ConclusionsConclusions• Time of YearTime 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 WeekDay 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.


• Time of DayTime 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.


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

Potential ApplicationsPotential 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

Motorists’ Perceptions of Aggressive Driving: A Comparative Analysis of Ontario and California...

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