Effect of mobile phone use and aggression on speed selection by young drivers: A simulator study RSRPE conference, Nov 12 – 14, 2014 Cassandra Gauld Dr Ioni Lewis Dr Md Mazharul Haque Prof. Simon Washington CRICOS No. 00213J

Background: Mobile phones Crash risk increases by 3 (Elvik, 2011) Multiple Resource Theory (Wickens, 2008) Tendency to reduce speed; possibly more on hand-held than hands-free (e.g., Elvik, 2011; Haque & Washington, 2013; Tornros & Bolling, 2006)

Mobile Phone Use and Young Drivers (Petroulias, 2014)

Aggressive Driving Associated with Intended to have a negative impact on another driver (Lennon & Watson, 2011) Associated with other risky driving behaviours (e.g., speeding, erratic driving) (AAA Foundation for Traffic Safety, 2009) Estimated 56% of fatal crashes in the US from 2003 to 2007 involved an action typically associated with driver aggression; most common was speeding (AAA Foundation for Traffic Safety, 2009)

Young Driver Aggression (AAMI, 2012)

Rationale …little is known about how these behaviours may function in Research has amassed on mobile phone use and aggressive driving separately, however: …little is known about how these behaviours may function in combination to influence speed selection…

Main Aim To explore the impact of: driver aggression mobile phone use (Driving Anger Expression Inventory [DAX]; Deffenbacher et al., 2002) and mobile phone use (i.e., baseline, hands-free, and hand-held) on speed selection by young drivers aged 18 – 26 years

Hypotheses H1: There will be a significant interaction effect for mobile phone use condition and driving anger expression H2: There will be a significant main effect for mobile phone use condition H3: There will be a significant main effect for driving anger expression

Methodology- Participants N = 32; 16M, 16F Aged 18 – 26 years (M = 21.50, SD = 2.00) QLD driver’s licence: provisional (n = 11) or open (n = 21) Driving experience (M = 4.20, SD = 1.89) years 78% self-reported using a hand-held and 22% using a hands-free MP while driving

Methodology - Participants Low or high on driving anger expression determined by a median split on the Total Aggressive Expressive Index of the Driving Anger Expression Inventory [DAX] (Deffenbacher et al, 2002)

2. Materials/measures- Driving Anger Expression Inventory (DAX) (Deffenbacher et al., 2002) Hostile/Aggressive Expression (34 items; 3 subscales) * Verbal Aggressive Expression * Physical Aggressive Expression * Use Vehicle to Express Anger Total Aggressive Expression Index Adaptive/Constructive Expression (15 items, 1 subscale) *Adaptive/Constructive Aggression

2. Materials/measures cont… CARRS-Q Advanced Driving Simulator

2. Materials/measures cont… Mobile Phone Task Baseline Hands-free Hand-held (no MP) (Bluetooth) (hold MP to ear) *Mobile phone conversations were cognitive in nature (e.g., had to respond to a question, solve a verbal puzzle, or a simple arithmetic problem) (adapted from Burns et al., 2002)

3. Procedure 1. Self-report survey: Demographics, driving history, general MP use history, MP use while driving, and DAX etc Simulator: * 5km of suburban route at 60kph * Contained ‘normal’ traffic events * 3 starting points randomised across participants * Participants were instructed to drive as they normally would (incl.traffic signs) and to follow the signs towards the airport

3. Procedure cont… 3. Mobile phone task: * Conversations began before the start of the drive and were continuous until end * MP conditions counterbalanced across participants

Results X 2 X 3 Mixed Factorial ANOVA (level of driving anger expression; low, high) X (mobile phone use condition; baseline, hands-free, hand-held)

Results – Key Findings No significant interaction between level of driving anger expression and mobile phone use condition Significant main effect for mobile phone use condition No significant main effect for level of driving anger expression

Conclusions The combined effect of level of driving anger expression and mobile phone use condition did not result in significantly different speed selections Drivers reduced speed more when on hand-held phone than hands-free, thereby supporting some previous literature (e.g., Tornros & Bolling, 2005, 2006) and Multiple Resource Theory Drivers high in driving anger expression did not drive faster, thereby not supporting previous literature (e.g., Delhomme et al, 2012)

Implications 78% of young drivers in this study reported using a hand-held MP despite this behaviour being illegal While the young drivers selected a lower speed when using the hand-held, this may not outweigh the risk associated with compromising both cognitive and visual resources, also needed for safe driving Challenges for public education and law enforcement needed to mitigate this risk

Implications cont… While young drivers are at increased crash risk from both MP use and driver aggression; the relationship between these factors is unclear Did the increase in speed associated with aggressive drivers and the decrease in speed associated with mobile phone use resulted in a negligible net effect in the current study? Further research needed to investigate how these 2 risky factors impact on young driver behaviour and subsequent crash risk

Questions? c1.gauld@qut.edu.au CRICOS No. 00213J