The Dula Dangerous Driving Index: An investigation of reliability and validity across cultures

Abstract

The aim of this study is to further establish the validity and reliability of the Dula Dangerous Driving Index (DDDI). The reliability and validity of the instrument was investigated by comparing data from a US university sample, a US community sample, and a sample of Belgian traffic offenders. Exploratory and confirmatory factor analysis supported the presence of a four-factor structure with items for Drunk Driving forming a separate scale apart from items for Risky Driving, Negative Cognitive/Emotional Driving and Aggressive Driving. A multi-group confirmatory factor analysis with model constraints supported the validity of the DDDI. Inter-correlations revealed that the DDDI subscales are closely interrelated and uni-dimensionality of the measure was found in all three samples. This suggests the DDDI Total score can be used as a composite measure for dangerous driving. However, the validity of the subscales was demonstrated in the Belgian sample, as specific traffic offender groups (convicted for drunk driving, aggressive driving, speeding) scored higher on corresponding scales (Drunk Driving, Aggressive Driving, and Risky Driving, respectively), indicating that it is clinically meaningful to differentiate the subscales.Numerous studies have documented that aggressive driving is indeed a real problem (e.g., Canada Safety Council, 2001;Joint, 1995;Lajunen & Parker, 2001;Mizell, 1997;Sarkar et al., 2000;Rathbone & Huckabee, 1999; U.S. Department of Transportation, USDOT, 1998), though how much damage is done and whether or not it is increasing is a matter of debate (e.g., James & Nahl, 2000;Martinez, 1997;Sullman et al., 2007; USDOT, 1998). However, it seems aggressive driving is a construct that remains unclear in much of the literature. The following serves to elucidate the issue and provide the rationale for the division of the breadth of coverage in the Dula Dangerous Driving Index (DDDI) and its division into distinct subscales.A critical feature of interpersonal aggression is intent to harm, either psychologically (as with insults or gestures) or physically (e.g., Baron & Richardson, 1994; Geen & O'Neil, 1976; Goldstein, 1994;Felson, 2000). When applied to a vehicular context, intention is often implied but usually not truly known. A variety of aggressive driving definitions have been posited (e.g., Connell & Joint, 1996;Joint, 1995;Ellison-Potter, Bell, & Deffenbacher, 2001;Gulian, Matthews, Glendon, & Davies, 1989;James & Nahl, 2000;Mizell, 1997;Sarkar et al., 2000;Shinar, 1998); however, a common factor is that all include behaviors and cognitive and/or emotional states that make the driving situation more dangerous. Dula and Geller (2004) highlighted problems with defining driver aggression and posited that it is more useful to construe aggression as but one facet of dangerous driving. Dangerous driving encompasses Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the...

Examining relationships between anxiety and dangerous driving

“…Subscale scores are calculated by adding the items within each scale and alpha coefficients for all 3DI scales have ranged from .73 to .92. Evidence for concurrent, divergent, and predictive validity has been demonstrated (Dula, 2003;Dula and Ballard, 2003) and a recent cross-cultural confirmatory factor analytic project firmly established the theoretical legitimacy of the subscale distinctions (Willemsen et al, 2008). One of the studies in this work was conducted in Belgium, where the 3DI was translated into Dutch following the procedure described by Brislin (1980).…”

Validity of the C-RDS Self-Reported Risky Driving Measure

“…Despite their popularity, surprisingly little research has been conducted on the reliability and validity of existing measures of self-reported risky driving. The DDDI is perhaps the best studied self-report measure and is the only measure that has been evaluated cross-culturally (Willemsen et al, 2008). While the full DDDI has often been used, its interpretation is uncertain because it includes aggressive, risky, and negative emotion driving tendencies.…”

“…In previous research the measures demonstrated good internal consistency (α = 0.83-0.93) and temporal stability (r = 0.55-0.73) (Dula & Ballard, 2003;Willemsen et al, 2008). Willemsen and colleagues (2008) reported that both the total score and the subscales discriminate between traffic offenders and non-offenders.…”

“…The reliability and validity of self-report measures have relied on other self-reported measures such as traffic violations, reported motor vehicle crash involvement, and archival police-reported driver history records (Shope & Bingham, 2002;Dula & Ballard, 2003;Willemsen et al, 2008). No studies have compared self-report measures with objective measures of risky driving using instrumented vehicle data, presumably because there have been few naturalistic driving studies due to their complexity and expense.…”

A Social-Cognitive Model of Driver Aggression: Taking Situations and Individual Differences into Account

“…However, males are more likely to demonstrate actual aggressive behaviors while driving than females, though males and females report similar levels of negative emotions while driving (e.g., Willemsen et al 2008).…”