Measures

This longitudinal study looks at individuals‟ responses to two questionnaires completed approximately 12 months apart, using several different scales of measurement. The questionnaires were designed to measure adolescent attitudes towards driving.

6.4.3.1 Questionnaire 1 („Time 1‟)

Part one of the questionnaire („Time 1‟) was divided into three sections (Chapter Five): i) Adolescent road behaviour (questions taken from the Adolescent Road User Behaviour

Questionnaire - ARBQ, Elliott and Baughan, 2004; Appendix A)

ii) Attitudes and intentions to engage in speeding behaviour (questions were extracted from the „Extended TPB scale‟ and included measures of moral norm; Parker, Manstead & Stradling, 1995; Appendix B)

iii) Attitudes to „speeding‟, „drink-driving‟ and „not wearing seat belts‟ (questions adapted from Parker, Manstead, Stradling and Senior‟s (1998) DAQ; Appendix C).

Some of the Likert scales for items in the questionnaire were randomly reversed to encourage participants to think about each question. When answers to reversed questions were reversed back to the correct direction, high-risk drivers and people with positive (high-risk) attitudes towards high-risk driving practices scored high on all three scales (the ARBQ scale, the TPB speeding scale and the DAQ scale).

Section 1: Adolescent Road Behaviour

In the first section, Elliott and Baughan‟s (2004) Adolescent Road User Behaviour Questionnaire (ARBQ) was used to measure road behaviour (Appendix A). These items were divided into three subscales that measured „Unsafe Road Crossing Behaviour‟, „Play and Social Activity on the Road‟ and „Planned Protective Behaviour on the Road‟. Elliott and Baughan (2004) reduced their scale from 43 items to 23 items because they felt that when the full scale was used in conjunction with other self-report measures the questionnaires would be too long for self-completion. They arrived at 23 items after conducting a principal axis factor analysis on the original 43 item scale and selecting the eight items that loaded most strongly on „Unsafe Road Crossing Behaviour‟ and „Play and Social Activity on the Road‟ and the seven items that loaded most strongly on „Planned Protective Behaviour on the Road‟. After a second principal axis factor analysis using the shortened 23 items scale Elliott and Baughan (2004) reduced the ARBQ scale further to 21 items. The 21-item ARBQ scale was used in this study as recommended by Elliott and Baughan (2004).

For the purposes of directionality, the Likert scale for items measuring „Planned Protective Behaviour on the Road‟ (for example, ―wear bright or reflective clothing when riding a bike in the dark‖, ―use lights on your bike when it is dark‖) were reversed and the sub-scale was re-labelled „Non-engagement in Planned Protective Behaviour on the Road‟. Consequently dangerous road users were those participants who scored high on each of the three sections of the ARBQ. The reduced 21-item ARBQ scale therefore consisted of eight „Unsafe Road Crossing Behaviour‟ items (α = 0.78), eight „Play and Social Activity on the Road‟ items (α = 0.85) and five „Non-engagement in Planned Protective Behaviour on the Road‟ items (α = 0.75). All items were measured using a five point Likert scale (1 = never, 2 = hardly ever, 3 = sometimes, 4 = fairly often, 5 = very often). A derived Cronbach‟s alpha value of 0.84 was calculated for all 21 items (Chapter Five, Table 5.2, page 108).

Although the full 43-item Adolescent Road User Behaviour Questionnaire was printed, only the 21 items from the reduced 21-item scale were used in statistical analysis. The reason the full scale was printed was that a second study unrelated to this thesis was running simultaneously validating the use of the 43-item ARBQ in NZ (Sullman & Mann, 2009).

Section 2: Attitudes and Intentions to Speed

The „Extended TPB scale‟ (Parker, Manstead and Stradling, 1995) was used to measure pre- drivers‟ attitudes and intentions to speed (referred to as the TPB speeding scale in this study), which included measures of personal norm (moral norm and anticipated regret, Appendix B). As Parker, Manstead et al. (1995) designed the extended TPB for their study on drivers, only those questions which were deemed to be relevant to pre-drivers were included in this study. There were 13 items in total (one moral norm, two anticipated regret, four attitude items, two subjective norm, three perceived behavioural control and one measure of intention) taken from Parker, Manstead et al.‟s (1995) original questionnaire and the wording slightly modified so that pre-drivers could reasonably answer the questions.

Some of the TPB components were measured using more than one item (for example, attitudes to speeding were measured using four items), responses to each of these facets were added together and averaged. Of the three perceived behavioural control items (PBC) only one was used in the statistical analysis in this study (―My refraining from speeding would be easy/difficult‖) because of the low Cronbach‟s Alpha produced when the three items were combined (α = 0.25; Chapter Five, Table 5.1, page 108). Parker, Manstead et. al (1995)

produced low Cronbach‟s Alphas for PBC in their study and consequently they chose to use the one PBC item that had correlated most highly with the belief-based measure of PBC. Parker, Manstead et. al (1995) calculated the belief-based measure of PBC by multiplying ratings for a set of salient control beliefs by the perceived power of each control factor to inhibit or facilitate performance and then summing the products).

The calculations and correlations conducted by Parker, Manstead et al. (1995) could not be performed in this study because participants were pre-drivers and could not rate internal or external factors that affect driving (i.e., their control beliefs) nor the frequency they encountered them (which would have produced an indication of the power of these control factors). A decision was made to use only one PBC item in the statistical analysis in this study. This decision was based partly upon Parker, Manstead et al.‟s (1995) suggestion but also on the results of Cronbach‟s Alphas conducted on the complete TPB scale. When the two PBC items were removed from the complete TPB scale the Cronbach‟s Alpha value increased from 0.72 to 0.76 (Chapter Five, Tables 5.1 and Table 5.2, page 108).

After removing two PBC items, 11 items were used to measure the components of the „Extended TPB scale‟ in this study. The items were measured using a seven point Likert scale with the end points being appropriate to the question (for example: 1= Strongly agree, 7= Strongly disagree; 1= Very likely, 7= Very unlikely; 1= Very easy, 7= Very difficult), the Cronbach‟s Alpha for all items was 0.76 (Chapter Five, Table 5.2, page 108).

Section 3: Attitudes to Driving Violations

The DAQ was used to assess attitudes towards driving violations such as „speeding‟, „drink- driving‟ and „not wearing seat belts‟. There were 22 questions (nine „speeding‟ items, eight „drink-driving‟ items and five attitudes to „not wearing seat belts‟ items). 16 items were taken from Parker et al.‟s (1998) 40-item DAQ scale (see Appendix C). The DAQ consisted of four sub-sections (10 items in each section) measuring attitudes towards: „drink-driving‟, „speeding‟, „over-taking‟ and „close following‟.

The 16 items from the original 40-item DAQ used in this study only addressed attitudes to „speeding‟ and „drink-driving‟ as it was felt that some pre-drivers might not have any knowledge about over-taking and close following. A new subscale, attitudes towards „not wearing seat belts‟, was created to measure adolescent attitudes towards wearing seat belts in cars.

From the original DAQ scale, seven items from the 10-item „drink-driving‟ subscale were chosen to be used in this study. Three „drink-driving‟ items from the original subscale measuring attitudes towards breath-testing and knowledge of the legal blood alcohol limit were removed because as participants were below the legal drinking age it was assumed that they may not know about legal limits or breath-testing. A new item (“it‘s ok to drink and drive”) was added to the „drink-driving‟ subscale in this study. The Cronbach‟s Alpha for the eight items in the attitudes to „drink-driving‟ subscale was 0.68 (Chapter Five, Table 5.2, page 108).

From the original DAQ scale only nine items on „speeding‟ were used in this study. One item, namely “I know exactly how fast I can drive and still drive safely”, was omitted because it was felt that it would not have been applicable to the pre-drivers answering the questionnaire. The Cronbach‟s Alpha for the nine items in the attitudes to „speeding‟ subscale was 0.73 (Chapter Five, Table 5.2, page 108).

A third subscale on „attitudes to not wearing seat belts‟ (i.e., what they felt about people travelling in cars without wearing seat belts) consisting of five questions was created for the purposes of this study. Some of the questions used in the other two sections on „speeding‟ and „drink-driving‟ were re-worded so that they could be applied to attitudes towards non-use of seat belts. The Cronbach‟s Alpha for the five items in the attitudes to „not wearing seat belts‟ subscale was 0.76 (Chapter Five, Table 5.2, page 108).

All items were measured using a five point Likert scale (1 = Strongly agree, 5 = Strongly disagree). The Cronbach‟s Alpha for the 22-item DAQ scale was 0.82 (Chapter Five, Table 5.2, page 108).

6.4.3.2 Questionnaire 2 („Time 2‟)

The second questionnaire (see Appendix H) consisted of three sections:

i) Re-assessment of driving attitudes and intentions to speed (eight items from the first questionnaire; Appendix F)

ii) Sensation seeking behaviour (AISS, Arnett, 1994; Appendix D)

iii) Self-reported engagement in „Errors‟, „Lapses‟ and „Violations‟ whilst driving (DBQ, Parker, West et al., 1995; Appendix E).

Section 1: Re-assessing Driving Attitudes and Intentions to Speed

The first section was designed to establish whether attitudes and intentions had changed during the intervening 12-month period as adolescents went from being pre-drivers to drivers. Eight items from the first questionnaire were replicated in this section. Four of the items that measured attitudes to speeding were included (responses to the four items were added together and averaged), along with one item on speeding intention. Three items from the DAQ measuring attitude towards „speeding‟, „drink-driving‟ and „not wearing seat belts‟ were also included (Appendix F).

Section 2: Sensation Seeking Behaviour

In the second section the AISS (Arnett, 1994) was used to measure sensation seeking tendencies. The scale consisted of 20 items that formed two sub-scales: „Novelty‟ and „Intensity‟ (Appendix D). Each subscale had ten items. The „Intensity‟ scale assessed the need for stimulation and experiences that provide intense sensory input (e.g., „„When I listen to music, I like it to be very loud‟‟, „„It would be interesting to see a car accident‟‟, „„I like a movie with a lot of explosions and car chases‟‟), whereas the items in the „Novelty‟ scale referred to the openness to experience (e.g., „„I can see how it would be interesting to marry someone from a foreign country‟‟, „„I would like to travel to strange, far-away places‟‟, „„I think it‘s fun and exciting to perform or to speak before a group‟‟).

Subjects were asked to indicate the extent to which the items describe them on a four point Likert scale (1 = describes me very well, 2 = describes me somewhat, 3 = does not describe me very well, 4 = does not describe me at all). Each subscale contained ten items that were averaged (after reversing back some of the items that had been reversed) to find a total score. High scores on both the sub-scales and on total AISS score (the combined „Novelty‟ and „Intensity‟ scores) were indicative of high sensation seekers. The Cronbach‟s Alpha for the „Intensity‟ subscale was 0.59, the „Novelty‟ subscale was 0.49 and the whole 20-item AISS scale was 0.66.

Section 3: Driver Behaviour Questionnaire (DBQ)

In the third section the DBQ was used to measure the frequency of drivers‟ self-reported behaviour on the road (Appendix E). The DBQ was originally designed by Reason et al. (1990) and consists of three subscales that measure the frequency of engagement in „Errors‟, „Lapses‟ and „Highway Code Violations‟ whilst driving. Driving „Errors‟ refer to mistakes or omissions that are made whilst driving (for example, “Brake too quickly on a slippery road,

or steer the wrong way in a skid”), „Lapses‟ are harmless mistakes that are made whilst driving that are caused by lapses in attention (for example, “Hit something when reversing that you had not previously seen”) and „Highway Code Violations‟ are deliberate deviations from safe driving practice (for example, “Race away from traffic lights with the intention of beating the driver next to you”). This measurement scale has been found to correspond highly with observed driving behaviour (Rolls et al., 1991).

Although there are several different versions of the scale the version chosen for this study consisted of 24 items in total; each of the subscales were composed of eight items (Parker, West et al., 1995). All violations were „Highway Code violations‟ (Appendix E). „Aggressive violations‟ (aggressive expressions of hostility towards other road users or drivers) were not included in the version of the DBQ used in this study because in previously conducted studies they produced low Cronbach‟s Alphas. Items consistently loaded on other factors and consequently „Aggressive Violations‟ explained only a very small amount of variance (5.4% in Sullman et al., 2002). „Aggressive Violations‟ have also been found to have no significant correlation with crash involvement (Gras, Sullman, Cunilla, Planes, Maria Aymerich & Font-Mayolas, 2006; Sullman et al., 2002). For this reason it was decided to follow Gras et. al‟s (2006) advice to omit aggressive violations from the DBQ.

Responses were measured on a six point Likert scale (0 = Never, 5 = All the time). The Cronbach‟s Alpha for the „Error‟ subscale was 0.83, for the „Lapses‟ subscale was 0.77, for the „Highway Code Violations‟ subscale was 0.82 and for the complete 24-item DBQ scale was 0.91.