Speeding poses a safety risk for the speeding driver and for other drivers on the road. This project aimed to understand time saving as a motivation for New Zealand drivers’ speeding in the context of other motivations for speeding, and to investigate the effect of education that aimed to improve participants’ understanding of the costs and benefits of speeding. The project comprised an initial survey about attitudes (850 responses), an educational intervention (534 completions), a follow-up survey (338 responses) and collection of real driving data from a small subsample of 25 drivers. A review of the literature showed that drivers tended to underestimate the time they would save by increasing their speed from a low speed and overestimated the time they would save by increasing their speed from a high speed. The benefits of speeding included time saving and enjoyment, while reasons for choosing lower speeds included safety, penalties and other financial costs. The literature suggested that drivers were generally aware of the costs and benefits of speeding, though might be less aware of the extent of each. The findings of the literature review were used in the development of the education intervention and the survey questions. In the literature, a commonly cited reason for speeding is that drivers want to arrive at the destination faster. Drivers who choose to speed to save time are those whose speeding behaviour falls into the violation category, as opposed to accidental lapses and other speeding behaviour. They make a conscious decision that the benefit of increasing speed (arriving at their destination sooner) outweighs the costs of speeding (financial, safety, possible penalties). If that cost-benefit decision is based on incorrect information, providing correct information may result in a different outcome. For example, the driver’s decision to speed may be based on an inflated estimate of the time they may save and an underestimate of the increased safety risk. If the driver instead has correct information about time saving and risk they may make a different speed choice. The initial survey of respondents in the present study found that choosing to speed to save time was not a motivation for all drivers. Just under one-third (32%) of drivers agreed that when they chose to speed it was to arrive at their destination sooner, while nearly half (48%) disagreed. Respondents were also asked to estimate the time savings from increasing their speed in two different scenarios. In the low-speed scenario, with a speed change from 50km/h to 60km/h, three-quarters (72%) of drivers underestimated the amount of time they would save. In the higher-speed scenario, with a change from 95km/h to 110km/h, more than half (60%) overestimated the time they would save. Drivers who aimed to travel over the speed limit in both 50km/h and 100km/h zones felt the speed limits were too low. These drivers were younger and more likely to agree that they chose to speed because they would get to their destination sooner. The majority of drivers (71%) recognised that increasing speed increased fuel consumption and most estimated the degree of the increase within five percentage points. However, under one-third (30%) of respondents estimated the fuel saving correctly. Nearly half (46%) of the drivers reported that they chose not to speed because of the increased fuel costs. Increasing understanding of the fuel costs of speeding could change the way other drivers evaluate the costs and benefits of speeding. Males and females had different reasons for speeding or not speeding. Female drivers were more likely to agree they chose not to speed because of the risk of crashing and the penalties for being caught. They were less likely to agree they chose to speed because they believed it was safe or because of the behaviour of other drivers. Younger drivers responded differently from older drivers. Younger drivers were more likely to choose to speed because of other traffic and because they believed it was safe to do so. Younger drivers were more likely to choose not to speed because of the financial costs of fuel and the extra wear and tear on the car. More commonly, respondents’ preferred speeds and definitions of speeding matched the popular understanding of Police speed enforcement thresholds. For example, in 50km/h zones, nearly one-third (30%) considered they would be speeding at 55km/h and a further third (33%) at 60km/h. In 100km/h zones, substantial proportions considered themselves to be speeding at 105km/h (18%) or 110km/h (36%). Identifying speeds on 5km/h margins may also be related to the intervals displayed on car speedometers or just a tendency to round numbers to the nearest five. There was a correlation between drivers’ preferred speed and their definition of speeding, with their preferred speed almost always falling below their definition of speeding. This finding suggests that people’s speed choice could be influenced by changing their definition of speeding. The education intervention was offered both online and in hard copy. Respondents completed a standard information package and then were invited to participate in the follow-up survey. Two national interventions took place between the two surveys: the Police Safer Summer road safety campaign, which featured a lowered speed enforcement threshold over the 2013/14 Christmas holiday period, and a NZ Transport Agency (the Transport Agency) advertising campaign targeting speed choice. Under one-third (32%) of respondents reported they learned something new from the education material but a higher proportion, nearly half (47%) reported they intended to change their driving as a result. The education material could have acted as a reminder to those who already knew the content, and so still affected respondents’ attitudes. The preferred speeds respondents reported in the follow-up survey decreased from the initial survey. Nearly half of respondents reported lower preferred speeds in 50km/h zones (40%) and 100km/h zones (41%) in the follow-up survey. The mean preferred speeds decreased by 1.1km/h and 1.2km/h respectively. Changes in preferred speed were correlated with changes in definitions of speeding. Drivers who decreased their numeric definition of speeding were more likely to report a lower preferred speed. Many drivers recognised that exceeding the speed limit resulted in increased crash risk. In the initial survey more drivers agreed they chose not to speed due to the increased severity of a crash than the increased likelihood of a crash. Of all the reasons to choose not to speed included in the survey, drivers most strongly agreed they chose not to speed due to safety concerns. This finding is consistent with surveys conducted in other countries. There was little shift in drivers’ views on their reasons for speeding in most areas investigated in the follow-up survey. The comparison between the pre- and post-education intervention surveys suggests the education intervention may have changed many respondents’ attitudes towards speed which in turn may lead to a change in their driving behaviour. Changes in actual driving behaviour following the same intervention were explored in a small sample of drivers by recording driving behaviour with data loggers that recorded information about the speeds drivers travelled. The driving behaviour measured through the use of the data loggers did not identify any significant changes before and after the education. It may also be possible that the data loggers themselves acted as an intervention that altered participants’ driving behaviour, increasing the difficulty of detecting change in response to the intervention. It is important to also note that the sample size was small limiting the possibility of detecting statistically significant differences between the before and after measurements for participants and between control and intervention groups. Further investigation with a larger sample group is recommended. New Zealand drivers’ attitudes to speeding are consistent with those of drivers internationally as described in the literature. The increased risk of crashing and the increased severity of crashes, should they occur, is well understood and drivers most commonly choose not to speed because of those risks. Drivers’ definitions of speeding and preferred travel speeds were closely linked to each other and appeared to be linked to enforcement thresholds, suggesting that changing definitions of speeding may be a way to influence drivers’ speed choices. Drivers do not have a good understanding of how much time they would save by speeding. Some drivers choose to speed because they want to save time, but generally underestimate time savings from increasing low speeds and overestimate time savings from increasing high speeds. Providing information about the costs and benefits of speeding was the basis of the education intervention. The intervention was inexpensive to develop and distribute and appears to have contributed to a change in some attitudes towards speeding including self-reported preferred speeds and definitions of speeding. The findings support the conclusion that drivers’ attitudes towards speeding may be changed through the provision of information on the costs and benefits of speeding. The findings do not allow definitive conclusions to be drawn about the extent attitudinal change results in behaviour change. The researchers recommend further exploring: • opportunities to change drivers’ definitions of speeding and the effect changes in the definition of speeding could have on preferred travel speed • education interventions targeting individuals’ differing levels of knowledge of the costs and benefits of speeding • the methods drivers use to calculate time savings, which may assist in targeting the content of education interventions. • driver behaviour through larger scale data logger studies, which could identify changes in driving behaviour that are not significant in smaller samples. (Author/publisher)
Samenvatting