Traffic Offences: Planned or Habitual? Using the Theory of Planned Behaviour and habit strength to explain frequency and magnitude of speeding and driving under the influence of alcohol

This study addresses the socio‐cognitive determinants of traffic offences, in particular of speeding and drinking and driving. It has two aims: (1) to test the hypothesis of a direct effect of habits on offences (i.e., independent of intentions) by employing a specific measure of habits (i.e., the SRIH) and (2) to analyse the offences by taking account of three distinct parameters: Frequency, usual magnitude (i.e., the most frequent deviation from the law) and maximal magnitude (i.e., the greatest deviation occasionally adopted) in order to represent more accurately the variability of the offending behaviours. A total of 642 drivers replied to a questionnaire. The results corroborate the idea that intention and habit are distinct and direct determinants of offences. The use of the SRIH dismisses the criticisms made with regard to the measure of past behaviour. The distinction between the three behavioural parameters proves to be relevant, as their determinants are not exactly similar. Finally, attitude and subjective norm had direct effects on the maximal magnitude and/or on the frequency of the offence. The discussion concerns the contribution of this study to the analysis of offences as well as its limitations and addresses the theoretical plausibility of the direct effects of attitude and the subjective norm.     

The effects of a rectangular rapid-flashing beacon on vehicle speed

In 2008, nearly 31% of vehicle fatalities were related to failure to adhere to safe vehicle speeds (National Highway Traffic Safety Administration [NHTSA], 2009). The current study evaluated the effect of a rectangular rapid-flashing beacon (RRFB) triggered by excessive speed on vehicle speed using a combined alternating treatments and reversal design. The percentage of vehicles traveling above 41 mph (66 km per hour) decreased by 20%, and speed distributions showed a shift toward lower speeds during the RRFB condition.     

LARGE-SCALE REDUCTIONS IN SPEEDING AND ACCIDENTS IN CANADA AND ISRAEL: A BEHAVIORAL ECOLOGICAL PERSPECTIVE

We assessed the effects of posted feedback and warning ticket programs on speeding and accidents in two cities. In Experiment 1, speeding feedback signs were effective even when 10 were used in Dartmouth, Nova Scotia, and reductions in speeding were associated with reductions in accidents. The effectiveness of the signs was correlated with the number of intersections and residences within 0.5 km beyond them, and the signs had no effect on untreated streets. In Experiment 2, posted feedback and a warning program reduced speeding and accidents on 14 streets in Haifa, Israel.     

A comparison of the effects of posted feedback and increased police surveillance on highway speeding

A counterbalanced, reversal design was used to compare the effectiveness of posted feedback and increased police surveillance in reducing speeding on two urban highways. Drivers' speeds were measured using a concealed radar unit. During public posting, a large highway sign, which listed the percentage of drivers not speeding during the preceding week and the best record to date, was erected on each street. Use of the feedback sign alternated with periods of baseline and periods of increased police surveillance and ticketing. During increased police surveillance, highly visible, stationary police radar patrols were established along the highways for either 30 min or 60 min per day, 5 days per week. Results indicated that although public posting was highly effective in reducing the percentage of speeding drivers, increased police surveillance was not. Thus, since the feedback sign required only 30 min per week to maintain, public posting was at least 10 times more efficient in controlling speeding than was police surveillance and ticketing.     

A replication of the use of public posting in traffic speed control

In an attempt to replicate several previous studies, a reversal design was used to assess the effects of publicly posted feedback on vehicle speed reduction. The intervention phases consisted of daily posted feedback that supplied drivers with either accurate or inaccurate information regarding the percentage of vehicles exceeding the speed limit on the road. Results from the two feedback conditions indicated no speed reduction in comparison to baseline levels. These results are discussed in light of previous studies that found strong effects for such feedback. Baseline levels of driver compliance and methodological differences may limit the effectiveness of posted feedback in reducing speeding.     

An application of the prototype willingness model to drivers' speeding behaviour

We tested the prototype willingness model (PWM). The participants (N = 198) completed online questionnaire measures of PWM constructs (Time 1) and subsequent speeding behaviour (Time 2). Path analyses showed that the PWM accounted for 89% of the variance in subsequent (self‐reported) speeding behaviour. This significantly exceeded the variance accounted for by the theory of planned behaviour. In line with the PWM, both behavioural intention and behavioural willingness had direct effects on behaviour. Behavioural willingness had a significantly larger effect. Attitude and subjective norm both had indirect effects on behaviour through both behavioural intention and behavioural willingness. Prototype (similarity) perceptions had indirect effects on behaviour through behavioural willingness only. The findings support the notion that driving is governed by reactive decision‐making (willingness), underpinned by prototype perceptions, attitudes and subjective norms, to a greater extent than it is deliberative decision‐making (intentions), underpinned by attitudes and subjective norms. The implications for safety interventions are discussed.     

The time-saving bias, speed choices and driving behavior

When drivers are asked to estimate how much time can be saved by increasing speed, they generally underestimate the time saved when increasing from a relatively low speed and overestimate the time saved when increasing from a relatively high speed. This time-saving bias has been demonstrated to affect drivers’ estimations of driving speed as well as drivers’ personal choice of speed. Specifically, drivers with a high time-saving bias chose unduly high speeds, which sometimes results in speeding, more frequently than drivers with a lower degree of the bias. This study sought to determine whether this relationship would be mediated by individual differences in driving behavior – including drivers’ attitudes, norms and habits regarding speeding behavior as well as their level of aberrant driving behavior (committing aggressive or ordinary violations, errors or lapses in driving, measured by the Driver Behaviour Questionnaire). The results showed that the time-saving bias predicted estimations of required speed better than any of these factors, and also better than drivers’ age, gender, education and income, as well as the number of years they have had a license and their monthly driving kilometrage, their prior speeding violations and crash involvement. In predicting drivers’ personal speed choices, the time-saving bias was second only to the frequency of committing ordinary violations.     

Self-reported Attitude Towards Speeding and Its Possible Consequences in Five Different Road Contexts

Driving above the permitted speed limit is a common violation on the roads of Great Britain. Moreover, speeding is associated with negative consequences in the form of damage, injury and fatal road traffic accidents. The aim of this study was to assess, by means of self-report, the prevalence of this social problem across five different contexts: a residential road, a busy shopping street, a dual carriageway, a winding country road, and a motorway. The extent to which speeding was perceived to be associated with negative consequences was also assessed. Results suggest that most drivers make judgements about the type of road on which they are driving and the degree of speeding that is acceptable, and that their intentions to speed vary accordingly. Some drivers reported a consistent intention to speed, however, and these people were characterized by greater general deviance on the road (e.g. high violation score), rather than by a stronger tendency to underestimate the negative consequences. In general, however, younger people and those with less regard for negative consequences reported stronger intentions to speed. These results are discussed with reference to strategies for addressing the problem of speeding. © 1997 John Wiley & Sons, Ltd.     

An analysis of public posting in reducing speeding behavior on an urban highway

The effects of public posting on speeding behavior on an urban highway were assessed using a reversal design. During baseline the percentage of drivers speeding was measured with a concealed radar unit. During the daily posting condition a highway sign was installed which provided feedback on the percentage of drivers not speeding yesterday and the best record to date. This sign was then covered and reintroduced. Results indicated that the sign was effective in reducing speeding behavior. Furthermore, the effects were most pronounced in reducing the speeds of the faster drivers. Next, daily and weekly postings were compared with the sign alone without numerical feedback: results revealed that the weekly posting condition was as effective as the daily posting condition, but that the sign had no influence when numbers were not posted. Finally, the weekly posting procedure remained effective during a 6-month follow-up condition.     

Effects of public posting on driving speed in Icelandic traffic

We replicated a study by Van Houten, Nau, and Marini (1980) that had revealed reductions in vehicle speeding following the posting of percentages of drivers not speeding on a sign at roadside. Our subjects were drivers entering a residential area where the speed limit changed from 90 km/hr (55.9 mph) to 60 km/hr (37.3 mph). A total of 4,409 vehicle speeds were taken from two observation sessions per day for 20 consecutive weekdays. The intervention consisted of a single posting condition, in which a hypothetical daily percentage of drivers not speeding was posted on a feedback sign, followed by a double posting condition, in which a sign posting a best result was erected beyond the feedback sign. Results revealed a significant speed reduction from an average of 69.0 km/hr (42.9 mph) during baseline to 63.4 km/hr (39.4 mph) during single posting. Average speed during double posting was 62.9 km/hr (39.1 mph). The percentage of drivers exceeding 70 km/hr (43.5 mph) dropped from 41.0 during baseline to 20.5 during single posting. The significant speed reductions add to the generality of findings of similar studies in Canada and Israel and offer possible explanations for the failure of feedback posting to reduce speed in the U.S.