Effects of position of speed limit signs and the presence of speed camera on Malaysian drivers’ speed choice: An eye-tracking study

Speeding is one of the most common driving violations in the world including in Malaysia. Reducing speed-related fatalities is one of Malaysia’s strategies to improve road safety. The current study aimed to investigate the effect of speed limit sign positioning and the presence of speed camera on drivers’ judgments about the appropriate speed to drive and their associated eye movements. Twenty participants took part in the study, and thirty two images of roads with a range of actual speed limits were presented. In each picture the displayed speed limit was edited to 30% lower than what participants think is appropriate on average. Speed limit signs were either presented on the road or on the speed limit sign boards at the road sides, and a speed camera sign was either present or not. Drivers judged a lower appropriate speed to drive when the camera sign was present than absent, while there was a wider spread of differences between judged and displayed speed when the speed limit sign was presented on the board than on the road. Drivers were quicker in fixating and looked more at the general area in which the speed limit sign appeared. Therefore drivers’ visual attention across scenes may be manipulated by the sign positions. These low-cost interventions could be useful in managing speed choice in Malaysia.     

Stability in drivers' speed choice

Repeated speed measurements were obtained to examine drivers' consistency in speed choice. Drivers were observed at two locations along a route or for two days at the same location. Single carriageway roads were used with posted speed limits of 70 and 90 km/h. Correlation coefficients between repeated speed measures ranged from .49 to .81 for free-flowing vehicles. Higher consistency between measures was found where segments of the road were homogenous. Consistency in relation to speed limit varied as a function of roads and direction of travel. From 4% to 41% of the drivers observed legal speeds at both sites and between 43% and 100% travelled over the speed limits at both sites. The results are discussed in terms of using self-reported speed in driver surveys and modelling of driver behaviour.     

A comparison of self-nominated and actual speeds in work zones

Despite significant research on drivers’ speeding behavior in work zones, little is known about how well drivers’ judgments of appropriate speeds match their actual speeds and what factors influence their judgments. This study aims to fill these two important gaps in the literature by comparing observed speeds in two work zones with drivers’ self-nominated speeds for the same work zones. In an online survey, drivers nominated speeds for the two work zones based on photographs in which the actual posted speed limits were not revealed. A simultaneous equation modeling approach was employed to examine the effects of driver characteristics on their self-nominated speeds. The results showed that survey participants nominated lower speeds (corresponding to higher compliance rates) than those which were observed. Higher speeds were nominated by males than females, young and middle aged drivers than older drivers, and drivers with truck driving experience than those who drive only cars. Larger differences between nominated and observed speeds were found among car drivers than truck drivers. These differences suggest that self-nominated speeds might not be valid indicators of the observed work zone speeds and therefore should not be used as an alternative to observed speed data.     

Road signs depicting childrens's book illustrations temporarily reduce speed on urban roads

Speeding on urban roads is a major road safety problem. Police enforcement and speed humps are effective measures to prevent drivers from speeding. However, these measures may also elicit none compliance because of their restrictive nature. Therefore, non-compulsive measures that nudge drivers to adopt low speeds are also required. One such a nudge was evaluated: road signs displaying children’s book illustrations. These signs display illustrations which were created by the late illustrator and writer of books for toddlers, Dick Bruna, and are named ‘Dick Bruna signs’. The idea of the developers of these signs was that they will evoke feelings of caution and care in drivers and this will make them drive slower. To evaluate the effect, two studies were conducted. In the first study participants watched photos from the driver’s perspective. They had to report how fast they expected others would drive and how fast they themselves would drive. Participants reported speeds of others higher than their own speeds but the pattern was the same: speeds on photos with a Dick Bruna sign were approximately 4 km/h lower than on the same photos without a Dick Bruna sign and speeds were not significantly lower when a neutral sign such as an advertisement was visible. In the second study speeds were measured during seven consecutive weeks on five experimental roads and five comparison roads. On the experimental roads, during the week 3–5 a Dick Bruna sign was placed. Controlled for developments in speed on the comparison roads in the same period, mean speed was marginally significant lower, and the V85 speed and the proportion of speed offenders were significantly lower in only the first week after placement of the signs.     

The role of preference in speed choice

Individual differences with regard to speed preference may be a source of speed heterogeneity and conflicts in traffic, such as tailgating and dangerous overtaking. The main aim of the current study was to explore drivers’ speed preferences when driving for different reasons (saving money on fuel, driving safely, driving for fun or driving as usual) and the relationship of these preferences to observed speeds and self-reported speed. 193 drivers were interviewed at five different locations, and were asked about their speeds on roads they had just travelled. Drivers’ speeds on these roads were also sampled with a speed gun. The results showed large differences between speeds chosen for different driving purposes; the lowest speeds were chosen when the goal was economy and the highest when driving for fun. In addition, there were individual differences in speed preferences such that some drivers indicated that their usual speed was above what they believed was a safe speed while others indicated that they usually drove even slower than what they thought was safe. These differences may account for much of the speed heterogeneity observed in on-road behaviour. The results also showed that drivers’ speed choices are highly influenced by their usual speeds, even more so than their beliefs regarding what constitutes a safe speed, which may help explain non-compliance with speed limits. No relationship was found between speed choice and risk perception.     

Do drivers differ in their attitudes on speed limit compliance between work and private settings? Results from a group of Nigerian drivers

Existing evidence suggests that drivers, particularly those who work in companies with strong road safety cultures exhibit different sets of speeding attitudes and behaviours in work and private driving. Using Ajzen and Fishbein’s (1980) Theory of Planned behaviour (TPB) and on-road driving experiments, this study examined the self-reported and objective behaviour of driving within posted speed limits for a sample of fleet drivers. The findings show that the TPB explained up to 24% of the variance in intention to comply with speed limits. Drivers’ attitude emerged as the most significant predictor and strongest correlate with intentions to comply with the speed limit in both work and private vehicle.Further analysis revealed participants had a higher intention to comply with speed limits in their work than private vehicle. Also, investigation of the relationship between TPB variables and observed speeding behaviour suggests that participants with higher intention to comply with the speed limit or high perceived behavioural control (PBC), exceeded the speed limit less often than those with lower intention to comply with the speed limit or low PBC. The findings have important theoretical and applied implications for development of better speed limit compliance interventions to improve driving behaviour, and road safety in general.     

Speed choice in relation to speed limit and influences from other drivers

Speeding is a general problem in traffic and exploring factors underlying the choice of speed is an important task. In the present paper, based on data from Swedish drivers on 90 km/h roads, drivers’ attitudes towards speeding and influences from other road users on the drivers’ speed choice were investigated. Unobtrusively recorded vehicle speeds were compared with drivers’ responses to questions concerning their speed choice (N=533). The present investigation replicates a previous study on 50 km/h roads, where a model including measures of attitudes and perceptions about others’ behaviour could explain about 15% of observed behaviour. In the present study, where a majority of the drivers observed exceeded the speed limit, a similar model could explain 41% of the variance in observed speed. Theoretical and practical implications of the results are discussed.     

An empirical analysis of driver perceptions of the relationship between speed limits and safety

In recent decades, it has become more common for speed limits to be set for political reasons rather than for safety reasons. As a consequence, the motoring public seems to have increasingly begun questioning the rationality of speed limits. This is evident in observed speed data that show that the majority of drivers routinely exceed posted speed limits. A key motivating factor in drivers’ tendency to exceed the speed limit is that they believe that the excess speed does not threaten safety. This paper, specifically studies this matter by using a survey that asked drivers how fast above the speed limit they feel they can drive before safety is threatened. A probabilistic model is estimated using data gathered from 988 drivers in Indiana. Estimation findings show that drivers’ perception of the speed above the speed limit at which they will receive a speeding ticket is a critical determinant of what they believe is a safe speed – suggesting that enforcement plays an important role in safety perceptions. Other variables found to be significant factors in determining the speed above the speed limit at which safety is first threatened include age, gender, being previously stopped for speeding, and drivers’ ethnicity.     

How fast would you (or should you) drive here? Investigation of relationships between official speed limit,perceived speed limit,and preferred speed

Speed is a critical risk factor, which makes its management the central point of the Vision Zero approach. Driving speed is influenced by speed choice, and in turn by the perception of the road parameters, as well as by the characteristics of drivers. Credible speed limits and self-explaining roads have been suggested as promising countermeasures; however, these rather theoretical concepts have only rarely been operationalized and quantified.The aim of this study was to investigate the relationships between speed indicators (official speed limit, perceived speed limit, preferred speed), as well as their differences, and to determine which road and personality characteristics influence them. Compared to previous studies, we introduced several innovative features, including a richer personality dataset based on three different questionnaires, a focus on all three types of roads (urban, rural, transition), and representative data on observed speeds.Using statistical models of the speed indicators, we found that both speed limit belief and speed choice, as well as their differences, are often influenced by the same characteristics. These are mainly more generous road design (higher road class, higher speed limit, and wider road) and the presence of additional elements (vegetation, pavements, and pedestrian crossings). These characteristics may help improve the credibility of speed limits and self-explaining performance.     

Pro-social behaviour in young passengers: Predictive utility of the social reaction pathway of the prototype willingness model

This study examined the social reaction pathway of the Prototype Willingness Model (PWM) to assess how attitudes, subjective norms, prototype perception (favourability and similarity), and risk perception influenced young passengers’ willingness to speak up to a driver exceeding the posted speed limit by either 5 km/h or 10 km/h. It was hypothesised that participants would be more willing to speak up to drivers’ travelling 10 km/h over the posted speed limit than 5 km/h over the posted speed limit. Further, it was hypothesised that the PWM constructs would significantly predict passenger willingness to speak up to a driver travelling 5 km/h over the posted speed limit and 10 km/h over the posted speed limit. Young Australians aged 17 to 25 years (N = 136, Mage = 19.32, 77.9% female) were recruited to complete a 30-minute online questionnaire. As predicted, passengers were significantly more willing to speak up to drivers travelling at 10 km/h over the posted speed limit than drivers travelling 5 km/h over the posted speed limit. Further, the results from a linear regression revealed that some of the PWM constructs were effective in explaining the variance in willingness to speak-up to drivers travelling either 5 km/h or 10 km/h over the posted speed limit. These findings address a gap in road safety research by shifting focus from the behaviour of drivers to the behaviour of passengers. The focus on the pro-social behaviour of speaking up to drivers performing risk taking behaviours may help to inform future educational campaigns and interventions designed to reduce young peoples’ involvement in road crashes.     

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.     

Explanations for “understating” in self-reported speeding behaviour

Self-report is a valuable methodology of social research, especially in regard to offending behaviour on and off the road. While assessing the validity of self-report is rarely easy, taking objective measures of drivers' speed choice behaviour does provide an opportunity to assess the correlation with subjective measures. Noting studies where this has been possible, research carried out by the author and colleagues in England which allowed similar assessments is discussed. Significant correlations resulted between reported and observed speed in all six surveys comprising the research, but they were of a low order. Analysis of the data showed a consistent and systematic bias towards drivers travelling above the 30 mph speed limit reporting their normal speeds as lower than those observed, with those travelling below the 30 mph speed limit reporting their speeds as higher than those observed. These patterns are discussed in light of other studies which have found tendencies either to overstate or to understate, and the possibilities that drivers either have difficulty reporting accurately or choose not to do so. Psychophysical limitations on accuracy of self-report and the social and cognitive processes that could mediate them are considered. In particular, the notion that drivers may seek to comply with normative speeds, and that these can be perceived as safer than complying with posted limits are discussed in light of normal police practice to tolerate low margins of excess speed.     

Application of the theory of planned behaviour to the prediction of objectively assessed breaking of posted speed limits

In two studies the Theory of Planned Behaviour (TPB) including moral norms, anticipated regret and past behaviour was applied to predicting intention to exceed the posted speed limit across different roads and objectively assessed speeding behaviour. All measures except behaviour were taken by self‐report questionnaires referring to different driving scenarios. The behaviour measures were based on performance in a simulator (Study 1) or unobtrusive on‐road speed camera assessment taken without driver awareness (Study 2) across roads with varying posted speed limits. Results are reported averaged across road types in both studies. In Study 1 (N = 83), 82% of the variance in intentions to speed was explained, with attitudes, subjective norms, perceived behavioural control (PBC), moral norms, anticipated regret and past behaviour being significant predictors. A total of 35% of the variance in speed as assessed on a driving simulator was accounted for with intentions, PBC, moral norms and previous accidents being significant predictors. In Study 2 (N = 303), 76% of the variance in intentions to speed was explained with attitudes, moral norms, anticipated regret and past behaviour being significant predictors. A total of 17% of the variance in speed as assessed on‐road was accounted for with intentions and moral norms being significant. Practical implications of the findings for road safety are discussed.     

Using a multi-user driving simulator system to explore the patterns of vehicle fleet rear-end collisions occurrence under different foggy conditions and speed limits

Vehicle fleet rear-end collisions (FRECs) are an extremely fatal type of traffic collisions on freeway and they usually occur in foggy weather. This study aimed to explore the patterns of vehicle fleet rear-end collisions occurrence under different foggy conditions and speed limits on freeway. A multi-user driving simulator system was used to conduct the experiment and the driving behavior data were collected from eight participants. The experimental results showed that as the fog density increased, the length of vehicle fleet decreased significantly, and drivers tended to keep a more stable car-following distance. The fog weather and short vehicle gap prompted drivers to react faster and brake harder in respond to the leading vehicle’s brake. In spite of the compensational behaviors, more FRECs were observed under heavy fog condition. Lowering speed limit can significantly reduce the FRECs under foggy conditions. As the speed limits reduced, drivers’ brake response time and speed variance significantly reduced. The study also found that drivers’ brake response time was negatively correlated with their positions in the fleet. Drivers in the front positions of the fleet had a longer response time than drivers in the back positions and thus were more likely to encounter collisions. The study generated a better understanding of drivers’ behavioral pattern in a vehicle fleet and the patterns of vehicle fleet rear-end collisions occurrence. The findings also shed lights on the design of driver assistance system for complex driving situations such as freeway driving under adverse weather.     

Examining the self-enhancement bias: professional truck drivers’ perceptions of speed,safety, skill and consideration

A sample of 1006 professional truck drivers were surveyed on their perceptions of self and average other speeds, consideration, relative safety, and relative skill. A disproportionate frequency of responses is found in the measures of speed, safety, and consideration, but not skill. In the measures of speed and consideration this bias is found to operate in a negative direction. Truck drivers are found to evaluate other road users negatively, they do not demonstrate ‘self-enhancement’ indicative of driver overconfidence. Drivers responsible for the biases are isolated from the sample using a method of triangulation. Background factors relating to driver characteristics and employment conditions are examined. Characteristics of the drivers’ employment indicate the perceptions are related to factors external to the drivers’ self-conceptions. These contrasts provide further support for the contention that the ‘self-enhancement bias’, as it appears in this sample, operates as a negative-other rationalisation.     

Estimating effectiveness of speed reduction measures for pedestrian crossing treatments using an empirically supported speed choice modeling framework

Pedestrian crossing treatments, such as Pedestrian Hybrid Beacons (PHBs) and Rectangular Rapid-Flashing Beacons (RRFBs), are traffic control devices implemented to help pedestrians safely cross busy or higher-speed roadways at midblock crossings and uncontrolled intersections. This study aims to assess the effectiveness of the PHB and RRFB by analyzing drivers’ speeding behavior under different roadway types with real-life traffic conditions. In order to understand the effect of pedestrian crossing treatments (i.e., PHB and RRFB) have on drivers’ speeding behavior, this paper analyzes four zones (i.e., one upstream zone and three consecutive downstream zones). For the four analysis zones, different indexes were computed which corresponds to the differences in drivers’ speed when encountered with the pedestrian crossing treatments. A grouped random effect hurdle beta regression model is estimated for the indexes, with a fixed effect hurdle beta model used for comparison and validating the importance of considering the grouped random heterogeneity across participants. The proposed analysis framework was validated by the means of an empirical driving simulator study, based on two urban roads in the Central Florida region, North Alafaya Trail (SR-434) and South Orange Blossom Trail (US-441). The results revealed that the proposed modeling framework reflects drivers’ difference in speed for the different pedestrian crossing treatments. The results suggest that with proper understanding of the PHB, the PHB can reduce drivers speed even beyond the location of the PHB. Meanwhile, the RRFB does have some effect in speed reduction beyond the location of the RRFB, however many drivers failed to acknowledge the RRFB. It is suggested that when drivers’ have proper education on the use of the PHB to reduce speed safely and for the installation of RRFB be on roads with two or less lanes and a speed limit less than 40 mph. While the main purpose of the pedestrian crossing treatments is to help pedestrians cross safely, speed reduction can be considered a byproduct as revealed in this study.     

Speed behaviour as a choice between observing and exceeding the speed limit

Despite speed behaviour being defined as a choice between several possible speeds, studies using theory of reasoned action or theory of planned behaviour to predict and understand speed behaviour have focused on exceeding and not on observing the speed limit. This study examines whether the evaluation of exceeding but also of observing the speed limit contributes to improving predictions of self-reported speed behaviour and determining intentions to produce each of these two behavioural options. For a specific driving situation (straight road with 90 km/h speed limit), 238 young male drivers reported the speed at which they would drive at and where asked to assess the theory of planned behaviour key constructs with respect to observing and exceeding the speed limit by at least 20 km/h. Results showed that the amount of explained variance of self-reported speed behaviour, as well as intentions to observe and to exceed the speed limit by at least 20 km/h, increased significantly when the evaluations of the two options were introduced in the same stepwise regression analysis. Theoretical and practical implications of the results are discussed.     

Effects of driver cell-phone use on driver aggression

Using 2 field procedures, the authors assessed impacts of cell-phone use on mild forms of driver aggression. Participants were 135 drivers traveling within a city of approximately 17,000 people in an otherwise little-populated region of western North Dakota. The authors videotaped the participants while a confederate driver in a low-status vehicle frustrated them. In Experiment 1, the confederate was traveling well under the posted speed limit. In Experiment 2, the confederate remained motionless at a stoplight that had turned green. When the confederate visibly talked on a hand-held cell phone (n = 67), male drivers exhibited their frustration by honking their horn more quickly and frequently than did drivers in no-cell-phone trials, and female drivers were more angry according to blind judgments of videotaped facial expressions that were compared with those of drivers in no-cell-phone trials (n = 68). The present results suggested that driver cell-phone use contributes to the growing crisis of roadway aggression.     

Judgments of mean speed and predictions of route choice

How are driving speeds integrated when speeds vary along a route? In a first study, we examined heuristic processes used in judgments of mean speed when the mean speeds on parts of the trip varied. The judgments deviated systematically from objective mean speeds because the distances driven at different speeds were given more weight than travel time spent on the different distances. The second study showed that when there was a 10–15 min pause during a travel the effect on the mean speed decrease was underestimated for driving speeds of 90 km/h and higher. In the third study, the objective mean speeds and the subjective biased mean speed judgments were used to predict choices between routes with different speed limits. The results showed that subjective judgments predicted decisions to maximize mean speed significantly better than objective mean speeds. Finally, some applied and basic research implications of the results were discussed.     

Does a prosocial attitude reduce risky driving behaviour under time pressure?

Time pressure could make drivers exhibit more risky driving behaviour. Attitudes can influence people’s behaviours, but few studies have explored the influence of prosocial attitudes on driving behaviour. The purpose of this study was to explore the influence of prosocial attitudes on driving behaviour under time pressure. A 2 (high/low prosocial attitude) *2 (present/no time pressure) mixed design was used to investigate the interaction between prosocial attitude and time pressure on driving behaviour. Prosocial attitudes and time pressure have a significant main effect on driving behaviour. Drivers with high prosocial attitudes made lane changes at a greater distance from pedestrians and decelerated to a greater degree than drivers with low prosocial attitudes when interacting with pedestrians. Under time pressure, people drive faster and accelerate more quickly. Specifically, we found an interaction between time pressure and prosocial attitudes on driving behaviour. Drivers with low prosocial attitudes showed higher speeds than drivers with high prosocial attitudes under the time pressure scenario on foggy roads. The results showed that high prosocial attitudes lead to friendly interactions with pedestrians and careful driving in specific situations, even under time pressure. The present study not only expands the research on driving behaviour and attitude but can also provide some data support and guidance for driver selection and training.