Speed cameras, section control, and kangaroo jumps-a meta-analysis

Spot speed cameras in a series - Effects on speed and traffic safety

Reduced speeds and increased speed compliance are crucial for achieving increased road traffic safety, cutting across most Safe System interventions. Speed cameras have been shown to be effective in increasing speed compliance and reducing the number of fatalities and seriously injured. The speed cameras system in Sweden is different compared to many other countries, spot speed cameras are almost always placed in series along a road stretch. The aim of this study is to investigate the effects of this system on mean speeds, speed compliance, and on the number of fatalities and seriously injured. Including 20 years of data, the study applies before-after analysis to 361 speed measurement spots, and Empirical Bayes before-after analysis with control to crash outcomes on 202 road sections. The results show a mean speed decrease of 3.5 km/h for all vehicles and road sections, 7.9 km/h at cameras and 3.0 km/h between cameras. Furthermore, follow-up measurements showed that the effects were maintained long-term. Speed compliance increased 16 %-units, 42 %-units at cameras and 13 %-units between cameras. Though larger effects can be seen at cameras, there are still substantial effects on the enforced road sections between cameras. The cameras had an average effect of 38.6 % on decreasing fatalities and may also suggest a decrease for seriously injured, though not statistically significant. This study also shows that for roads that received both a decreased speed limit from 90 to 80 km/h and speed cameras, the mean speeds were reduced by additionally 3.6 km/h compared to roads with unchanged limits of 90 km/h. The combined effect on fatalities and seriously injured was a reduction by 61.6 % and 33.4 %. In conclusion, the Swedish strategy with spot speed cameras in a series led to an increased speed compliance and a comprehensive reduction in mean speeds and of the number of fatalities.

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

Examining enforcement coverage for speeding and red-light offenses across various populations and driver characteristics

Over the years empirical evidence has shown that traffic enforcement reduces traffic violations, crashes, and casualties. However, less attention has been paid to enforcement coverage across different populations and driver characteristics. The current study develops and explores a method for estimating police enforcement coverage, by comparing the share of drivers across several characteristics who received tickets from automatic speed and red-light cameras - as an objective estimate of offenses committed - to the share of drivers who received tickets through manual police enforcement. Using data from all speeding and red-light tickets issued to Israelis over a period of one and a half years, we found under-enforcement by police officers for female drivers, two-wheeled vehicle drivers (for speeding), and drivers with previous tickets. We found over-enforcement for younger drivers, truck drivers, and two-wheeled vehicle drivers (for red-light offenses). The findings suggest that the method developed in the research is able to identify groups of drivers who are over- or under-enforced. Police authorities can use this information to create evidence-based enforcement policies.

The evaluation of decorated camera housings - A driving simulator study

Traffic enforcement cameras can lead to unwanted side-effects. For instance, red-light cameras at intersections can increase the chance at rear-end collisions, probably caused by slowing down abruptly. Additionally, on the highways, speed cameras could lead to kangaroo-jumps in driving speed. Warning drivers about cameras is a possible solution. Cameras that are uncommonly decorated (e.g. colored in pink or in yellow) may provide better conspicuity compared to those in standard colors like gray. However, besides warning drivers about their presence, more conspicuity of cameras could also distract drivers from the primary driving task. Therefore, the impact of such decoration on safety is unclear. This study evaluates different decorated designs of the camera housing and how such decoration may influence camera's conspicuity and induce distraction while driving. Three camera colored-designs were evaluated (gray, pink, and a mixture of yellow and black) using a driving simulator. Fifty-four participants drove nine different conditions, i.e. three camera-designs in three roadway-settings (basic highway segments, intersections operating during the amber-phase, and intersections with a bicycle-lane). Subjective and objective measures allowed to assess if: 1) decorated camera housings increased conspicuity, 2) signs of distraction could be found, and 3) driving was influenced. In addition to the detection success rate, other eye-tracking parameters were: time-to-first-fixation, fixation count, and average and total fixation duration. Driving measures, i.e. speed, acceleration or deceleration rate, lane-keeping behavior, and minimum time-to-collision, were included to assess if the tested camera-designs impacted driving behavior. Moreover, a post-drive questionnaire assessed the participants' opinions. Using camera colored-designs improved the camera's conspicuity. However, driving measures remained comparable across the three camera-designs. Although the subjective data indicated some distraction from the decorated cameras, clear indications for an effect on traffic safety were lacking. Meanwhile, a little over half of the respondents supported camera decoration. The current study does not allow firm conclusions, and additional research is recommended.

The effectiveness of fixed speed cameras on Iranian taxi drivers: An evaluation of the influential factors

Background

The adherence to speed limits can reduce deaths associated with road traffic injuries (RTIs) by more than a quarter. This study aimed to evaluate the effective factors on the speeding behavior of Iranian taxi drivers around fixed speed cameras.

Method

Telematics devices used in this study collected the location and speed of the vehicles. The units of analysis in this study were trips per camera, including 2.5 km before and after each camera. Linear regression analysis was used to identify kangaroo driving (KD), defined as trips with a significant V-shape in speed distribution around the camera. In the clustered camera zones, cameras were placed at regular intervals of approximately 3.5 km.

Findings

A total of 93,160 trips were recorded from 13,857,443 data points. There was an inverse association between drivers' age and KD with an odds ratio (OR) of 0.98 (95% confidence interval: 0.98-0.98). The intercity trips had a substantially higher probability of KD than urban trips (OR: 4.94 [4.73-5.16]). The tendency of drivers toward KD during the daylight hours vs. nighttime was significant for both urban (OR: 1.15 [1.06-1.25]) and intercity (OR: 1.18 [1.14-1.22]) trips. The 4 -8 a.m. period had the highest chance of KD in both urban (10.71% [7.41-14.53]) and intercity (44.13% [41.18-47.09]) trips. There was a significant decrease in the odds of KD inside the clustered camera zones (OR: 0.22 [0.20-0.25]).

Conclusion

The heterogeneous occurrence of KD in different locations and times indicates the necessity of evidence-based decision-making in urban planning to improve safe driving behaviors. The lower occurrence of KD in clustered camera zones could be a practical key to the effective control of speeding behaviors by helping in the efficient placement of cameras through sustainable development of cities and roads.

Unveiling the relevance of traffic enforcement cameras on the severity of vehicle-pedestrian collisions in an urban environment with machine learning models

PURPOSE

One of the leading causes of violent fatalities around the world is road traffic collisions, and pedestrians are among the most vulnerable road users with respect to such incidents. Since walking is highly promoted in urban areas to alleviate motor-vehicle externalities, it is paramount to understand the causes associated with vehicle-pedestrian collisions and their severity to provide safe environments. Although traffic enforcement cameras can address vehicle-vehicle collisions, little is known about their effectiveness with respect to vehicle-pedestrian incidents.

METHODOLOGY

In this study, we trained a set of machine learning models to forecast if a vehicle-pedestrian collision will turn into an injury or fatality, and the most suitable model was used to investigate the contributing features associated with such events with emphasis on the impact of traffic enforcement cameras. In addition to traffic enforcement camera proximity, features associated with the collision, weather, vehicle, victim, and infrastructure are included in the model to reduce unobserved heterogeneity.

RESULTS

Results show that a Linear Discriminant Analysis model surpasses other machine learning models considering the evaluation metrics. Results reveal that the age and gender of the victim, the involvement of larger vehicles in the collision, and the quality of the illumination are the causes associated with pedestrian fatalities. On the other hand, involvement of motorcycles and collisions that occurred in densely populated locations are the causes associated with pedestrian injuries.

CONCLUSIONS

This investigation demonstrates how to articulate machine learning into a vehicle-pedestrian crash analysis to understand the direction and magnitude of covariates in the corresponding severity outcome. Furthermore, it highlights the remarkable effect that traffic enforcement cameras and other features have on vehicle-pedestrian crash severity. These results provide actionable guidance for educational campaigns, enhanced traffic engineering, and infrastructure improvements that could be implemented in the analyzed region to provide safer transportation.

It's not a hard and fast rule: A qualitative investigation into factors influencing speeding among young drivers

INTRODUCTION

Research demonstrates that young drivers exceed the posted speed limit more frequently than older drivers, and this demographic is also subsequently overrepresented in road crash statistics. This behavior remains a worldwide problem despite legal enforcement efforts that have proven to have limited efficiency and/or produce counterintuitive results.

METHOD

Consequently, this study undertook a qualitative analysis in order to understand the factors that are perceived to both prevent and promote speeding behavior among young drivers, guided by self-determination theory (SDT). Focus groups were conducted with a total of 60 young drivers aged 17-25 years. An inductive thematic analysis approach was taken to analyze the data.

RESULTS

Findings revealed the following factors influence the prevention of speeding: (1) legal consequences were perceived to deter low-level speeding, (2) fear of injury was believed to prevent high-level speeding, and (3) speed awareness monitors were considered to be an effective countermeasure. Meanwhile, factors perceived to contribute to violating speed restrictions included: (1) perceiving it is safe to do so, (2) a perceived norm to speed, (3) emotions, and (4) unintentional speeding. According to SDT, the factors that were perceived to prevent speeding promote externalized self-regulatory processes and are therefore limited by short-term behavior change.

PRACTICAL APPLICATIONS

The findings have important implications for designing countermeasures aimed at young drivers, not least illuminating the need to have education and media campaigns that target and build drivers' perceived competence, autonomy, and relatedness in relation to speeding in order to promote longer term compliance.

Effects of interventions for preventing road traffic crashes: an overview of systematic reviews

BACKGROUND

Road traffic crashes (RTCs) are among the eight-leading causes of death globally. Strategies and policies have been put in place by many countries to reduce RTCs and to prevent RTCs and related injuries/deaths.

METHODS

In this review, we searched the following databases Ovid Medline, Embase, Cochrane Database of Systematic Reviews, Epistemonikos, Web of Science, and LILACS for reviews matching our inclusion criteria between periods January 1950 and March 2020. We did not apply language or publication restrictions in the searches. We, however, excluded reviews that focused primarily on injury prevention and reviews that looked at crashes not involving a motor vehicle.

RESULTS

We identified 35 systematic reviews matching our inclusion criteria and most of the reviews (33/35) included studies strictly from high-income countries. Most reviews were published before 2015, with only 5 published between 2015 and 2020. Methodological quality varied between reviews. Most reviews focused on enforcement intervention. There was strong evidence that random breath testing, selective breath testing, and sobriety checkpoints were effective in reducing alcohol-related crashes and associated fatal and nonfatal injuries. Other reviews found that sobriety checkpoints reduced the number of crashes by 17% [CI: (- 20, - 14)]. Road safety campaigns were found to reduce the numbers of RTCs by 9% [CI: (- 11, - 8%)]. Mass media campaigns indicated some median decrease in crashes across all studies and all levels of crash severity was 10% (IQR: 6 to 14%). Converting intersections to roundabouts was associated with a reduction of 30 to 50% in the number of RTCs resulting in injury and property damage. Electronic stability control measure was found to reduce single-vehicle crashes by - 49% [95% CI: (- 55, - 42%)]. No evidence was found to indicate that post-license driver education is effective in preventing road traffic injuries or crashes.

CONCLUSION

There were many systematic reviews of varying quality available which included studies that were conducted in high-income settings. The overview has found that behavioural based interventions are very effective in reducing RTCs.

Evaluating the effects of automated monitoring on driver non-compliance at active railway level crossings

Collisions between road users and trains at urban railway level crossings persist, despite active protection. The number of railway level crossings in most settings render their removal unfeasible. To effectively reduce or manage risk, alternative treatments are required. Increases in road and rail traffic invariably result in congestion issues at urban railway level crossings, which influences non-compliances by road users. Automated enforcement is one form of treatment that is being considered to reduce such non-compliances. This study conceptualised and adopted a before-after design to evaluate the effect of a conspicuous monitoring system on non-compliances by vehicular road users at an active level crossing. Baseline measurements of vehicle movements and level crossing status were recorded for two months. Conspicuous cameras and radar were subsequently installed, and a further month of data was recorded. Non-compliances with flashing lights were extracted and arranged into "must stop" and "should stop if safe to do so" categories, aligning with road rules at traffic lights. Non-compliances frequently occurred (N = 1,086) with most (94%) of the latter category and ascribed to a lack of an advanced warning before crossing closure. Analysis with Generalised Linear Models revealed that non-compliances where drivers must stop reduced by 36% (from 13.4% to 8.6%) following the introduction of a conspicuous automated monitoring system, even though no actual enforcement was performed. This study suggests that non-compliances at railway level crossings have the potential to be reduced through the introduction of automated enforcement similar to the one used at traffic lights.

The role of perceived legitimacy in understanding traffic rule compliance: A scoping review

BACKGROUND

Perceived legitimacy associated with rules and authorities is an important element for understanding and encouraging compliance with rules in the field of road safety, often more so than with a deterrence approach. Despite a growing interest in legitimacy in recent decades and in the psychological field in particular, its definitions and measurements appear to be heterogeneous, subject to debate and in need of a common theoretical framework. Therefore, one can expect these limitations to also concern the definitions and measurements of legitimacy in the field of road safety. However, no literature review related to this issue is currently available. This contribution therefore aims to fill this void by proposing a scoping review investigating, in the field of road safety, how legitimacy is defined, measured, related to compliance and what are its main determinants.

METHODS

A scoping review was conducted, based on research literature from eight databases and concerned with the perceived legitimacy of traffic rules or traffic enforcement and rule compliance or traffic violations. Twenty-six publications meeting inclusion criteria were retained. The characteristics and content of publications were analyzed to identify the relevant elements related to our research questions.

RESULTS AND CONCLUSION

The main results revealed that perceived legitimacy in the field of road safety can be related to different objects (i.e., traffic rules, traffic violations, traffic enforcement, institutions) that should be better delineated and differentiated in future research. While perceived legitimacy is generally associated with compliance with traffic rules, its theoretical definitions and measures in the field of road safety are heterogeneous and present validity issues which limit the comparability of studies and so the accumulation of knowledge for both theoretical research and road safety applications. No empirical study investigating the outcomes of perceived legitimacy beyond compliance was identified. Few empirical studies have investigated the determinants of perceived legitimacy. Most identified empirical studies were cross-sectional, which is a limitation to establishing causality in investigated relationships. Theoretical implications and research perspectives to improve studies on legitimacy in the field of road safety and develop a multidimensional model of the perceived legitimacy of traffic rules are therefore proposed and discussed.

A unified deterrence-based model of legal and non-legal factors that influence young driver speeding behaviour

Young driver speeding behaviour remains a large contributor to road trauma worldwide. In order to provide a more-in depth understanding of how to deter young drivers from this behaviour, this study developed and tested a model of the legal and non-legal factors that influence young driver's intentional speeding behaviour (exceeding the speed limit by more than 10 km/hr). A prospective survey design was conducted to measure the impact of perceptions of legal factors (including classical deterrence and reconceptualised deterrence variables) and non-legal factors (including the variables of fear of physical loss, material loss and perceived social sanctions, as well as the perception that it is safe to engage in the behaviour without being involved in a crash) at time 1, on engagement in speeding behaviour at time 2, which occurred 3 months later. A total of 200 participants aged 17-25 years completed both surveys (Mean age = 20.44 years). Using structural equation modelling, a unique model combining classical and extended deterrence theory, as well as prominent non-legal factors was created, and the variables were able to explain 41% of the variance in speeding behaviour. A high perceived severity of the punishment, experiencing direct punishment avoidance and perceiving that it is safe to speed were significant direct predictors. Meanwhile, there were also numerous significant partially mediated relationships found for both legal and non-legal variables. These findings provide important implications for both the application of deterrence-based theories in road safety and for improving countermeasures to deter young drivers more effectively from engagement in speeding.

Investigations of the Dynamic Travel Time Information Impact on Drivers’ Route Choice in an Urban Area—A Case Study Based on the City of Bialystok

Increasing traffic volumes in cities leads to common traffic congestions building up, especially during peak hours. To protect city dwellers from excessive fuel exhaust and traffic noise and to prevent drivers from time loss due to overloaded routes, it is important to inform them about real-time traffic conditions and possible delays in advance. Effectively influencing drivers’ decisions to divert from an original route choice in case of traffic hinderance is essential, and application of dynamic travel information in the form of variable message signs (VMSs) is believed to be effective in these terms. The paper examines drivers’ willingness to divert from an initial route choice due to the information provided on VMS boards. Their behavior was analyzed in terms of their response to everyday and artificially elongated travel times displayed on the VMSs. Maximum simulated elongation reached 200% and 300% of the initial state, depending on the characteristics of the pre-peak conditions. To assess the effectiveness of VMSs, the changes in traffic intensities were statistically analyzed. In general, apart from few significant differences, the results revealed drivers’ ignorance of the travel time information provided on the VMS, regardless of the extension of the original times.

Evaluation of penalty and enforcement strategies to combat speeding offences among professional drivers: A Hong Kong stated preference experiment

Speeding has been a great concern around the world due to the occurrence and severity of road crashes. This paper presents an evaluation of the effectiveness of different penalty and camera-based enforcement strategies in curbing speeding offences by professional drivers in Hong Kong. A stated preference survey approach is employed to measure the association between penalty and enforcement strategies and drivers' speed choices. Data suggest that almost all drivers comply with speed limits when they reach a camera housing section of the road. For other road sections, a panel mixed logit model is estimated and applied to understand the effectiveness of penalties and enforcement strategies on driver's speeding behaviors. Driving-offence points (DOPs) are found to be more effective than monetary fines in deterring speeding offences, albeit there is significant heterogeneity in how drivers respond to these strategies. Warning drivers of an upcoming camera-based enforcement section increased speed compliance. Several demographic and employment characteristics, driving history and perception variables also influence drivers' choices of speed compliance. Finally, besides penalty and enforcement strategies, driver education and training programs aimed at addressing aggressiveness/risk-taking traits might help reduce repeated speeding offences among drivers.

Safety of motorized two-wheeler riders in the formal and informal transport sector

Road fatalities are largely preventable problem with large socioeconomic impact. Due to the rapidly increasing population, transport systems and road infrastructure have not met the demand. The use of motorized two-wheeler vehicles has increased, as informal transport. However, evidence on their safety is scarce. The aim of this article is to examine the safety and social equity issues in MTW in the informal transport sector. Factors can be used to explain traffic collisions in MTW in the formal/informal transport sectors: design, rider behavior, road design, enforcement, and regulation of the informal transport sector. Evidence suggests that MTWs could be a common related to pedestrian fatalities. Informal transport drivers are typically poor, uneducated, young men who due to lack of other employment options move into the informal sector. Their vehicles are old, unmaintained and have a lack of protective equipment for themselves and their passengers. Young, male drivers speed, take risks and not use protective equipment. Users of informal transport live in the poorer peripheries of cities, which, have limited, inefficient or unaffordable public transport. The provision of transport has therefore become an often unrecognized, important social equity issue and studies are urgently needed on MTW in the informal transport sector.

A systematic cost-benefit analysis of 29 road safety measures

Economic evaluations of road safety measures are only rarely published in the scholarly literature. We collected and (re-)analyzed evidence in order to conduct cost-benefit analyses (CBAs) for 29 road safety measures. The information on crash costs was based on data from a survey in European countries. We applied a systematic procedure including corrections for inflation and Purchasing Power Parity in order to express all the monetary information in the same units (EUR, 2015). Cost-benefit analyses were done for measures with favorable estimated effects on road safety and for which relevant information on costs could be found. Results were assessed in terms of benefit-to-cost ratios and net present value. In order to account for some uncertainties, we carried out sensitivity analyses based on varying assumptions for costs of measures and measure effectiveness. Moreover we defined some combinations used as best case and worst case scenarios. In the best estimate scenario, 25 measures turn out to be cost-effective. 4 measures (road lighting, automatic barriers installation, area wide traffic calming and mandatory eyesight tests) are not cost-effective according to this scenario. In total, 14 measures remain cost-effective throughout all scenarios, whereas 10 other measures switch from cost-effective in the best case scenario to not cost-effective in the worst case scenario. For three measures insufficient information is available to calculate all scenarios. Two measures (automatic barriers installation and area wide traffic calming) even in the best case do not become cost-effective. Inherent uncertainties tend to be present in the underlying data on costs of measures, effects and target groups. Results of CBAs are not necessarily generally valid or directly transferable to other settings.

Discovering Speed Changes of Vehicles from Audio Data

In this paper, we focus on detection of speed changes from audio data, representing recordings of cars passing a microphone placed near the road. The goal of this work is to observe the behavior of drivers near control points, in order to check whether their driving is safe both when approaching the speed camera and after passing it. The audio data were recorded in controlled conditions, and they are publicly available for downloading. They represent one of three classes: car accelerating, decelerating, or maintaining constant speed. We used SVM, random forests, and artificial neural networks as classifiers, as well as the time series based approach. We also tested several approaches to audio data representation, namely: average values of basic audio features within the analyzed time segment, parametric description of the time evolution of these features, and parametric description of curves (lines) in the spectrogram. Additionally, the combinations of these representations were used in classification experiments. As a final step, we constructed an ensemble classifier, consisting of the best models. The proposed solution achieved an accuracy of almost 95%, without mistaking acceleration with deceleration, and very rare mistakes between stable speed and speed changes. The outcomes of this work can become a basis for campaigns aiming at improving traffic safety.

Impact evaluation of camera enforcement for traffic violations in Cali, Colombia, 2008-2014

INTRODUCTION

Cameras for detecting traffic violations have been used as a measure to improve road safety in different countries around the world. In Cali, Colombia, fixed cameras were installed in March 2012 on a number of roads and intersections. All camera devices are capable of detecting simultaneously the following traffic violations: driving over the speed limit, running a red light or stop sign, violation of the traffic ban schedule, and blocking the pedestrian crosswalk.

OBJECTIVE

To evaluate the impact of camera enforcement of traffic violations in Cali, Colombia.

METHODS

A quasi-experimental difference-in-differences study with before and after measurements and a comparison group was conducted. We observed 38 intervention areas and 50 comparison areas (250 m radius), during 42 months before and 34 months after the installation of cameras. Effects were estimated with mixed negative binomial regression models.

RESULTS

In intervention areas, after 12 months, there was a reduction of 19.2% of all crashes and a 24.7% reduction of injury and fatal crashes. In comparison areas, this reduction was 15.0% for all crashes and 20.1% for injury and fatal crashes. After adjusted comparisons, intervention sites outperformed comparison sites with an additional yearly reduction of 5.3% (p = 0.045) for all crashes.

CONCLUSIONS

The use of cameras for detecting traffic violations seems to have a positive effect on the reduction of crashes in intervention areas. A beneficial spillover effect was found as well in comparison areas; but more evaluations are needed.

Updated estimates of the relationship between speed and road safety at the aggregate and individual levels

Recent studies of the relationship between the speed of traffic and road safety, stated as the number of fatalities and the number of injury accidents, are reviewed and their results synthesised by means of meta-analysis. All studies were based on data fully or partly for years after 2000. Previously proposed models of the relationship between the speed of traffic and road safety, including the Power Model and an Exponential Model, are supported. Summary estimates of coefficients show that the relationship between speed and road safety remains strong. The Power Model and the Exponential Model both fit the data very well. The relationship between speed and road safety is the same at the individual driver level as at the aggregate level referring to the mean speed of traffic.

Evaluation of the Speed Control Cameras in the City of Lisbon

In Portugal, urban areas still have a high number of fatalities as a result of road crashes. In 2016, 78% of road crashes with victims, 62% with serious injuries and 54% with fatalities occurred in urban areas. Knowing where crashes occur and what circumstances contributed to these occurrences is the key to finding solutions that minimize injuries and deaths. At the end of 2016, as a safety measure, speed control cameras from SINCRO (Sistema Nacional de Controlo de Velocidade, the national speed control system), began to be installed in different parts of the country. The first application was in 2006 at several spots in the urban area of Lisbon. Cameras were installed in 20 of these locations. This study, using the location of the speed control cameras (which were only effective in 19 spots) and the 2004–2011 crash databases, sought to assess the effectiveness of the measure. The results showed that there was a positive effect on crash rates soon after implementation, but it was also perceived that this effect was attenuated in subsequent years. It is assumed that the reasons for this are due to the familiarization with the system, together with inefficient sanctioning of the violators, and additionally due to malfunctioning equipment not being repaired in a timely manner, which was evident to the users.

Recommend or mandate? A systematic review and meta-analysis of the effects of mandatory bicycle helmet legislation

If all cyclistswere wearing helmets, significant numbers of head injuries might theoretically be prevented. Mandatory bicycle helmet legislation increases helmet use but is a controversial measure. Results from 21 studies of the effects of mandatory bicycle helmet legislation on injuries among crash involved cyclists were investigated by means of meta-analysis and the effects of several potential biases were investigated. The summary effect of mandatory bicycle helmet legislation for all cyclists on head injuries is a statistically significant reduction by 20% (95% confidence interval [-27; -13]). Larger effects were found for serious head injury (-55%; 95% confidence interval; [-78; -8]). Among children, larger effects were found when legislation applies to all cyclists than when it applies to children only. There is no clear indication of the results being affected by publication bias. Publication bias may exist, but any existing biases seem to more or less outweigh each other. Results from meta-analysis do not indicate that the results are systematically affected by a lack of control for time trend bias, choice of comparison group or study design (before-after vs. case control). Summary effects may be somewhat overestimated because of a lack of control for potential confounding variables in some of the studies. However, such a bias, if it exists, is not likely to be large. Empirical evidence for the hypotheses that mandatory bicycle helmet legislation deters people from cycling and that helmet wearing leads to behavioral adaptation is mixed. In summary, mandatory bicycle helmet legislation can be expected to reduce head injury among crash involved cyclists. Some adverse effects may occur, but will not necessarily be large or long-lasting. People who may be deterred from cycling, are among those with the highest injury risk and the smallest health effects from cycling. If the overall goal is to improve safety for all cyclists and to increase cycling, mandatory bicycle helmet legislation should be supplemented by other measures, especially improved bicycle infrastructure.

Bicycle helmets - To wear or not to wear? A meta-analyses of the effects of bicycle helmets on injuries

A meta-analysis has been conducted of the effects of bicycle helmets on serious head injury and other injuries among crash involved cyclists. 179 effect estimates from 55 studies from 1989-2017 are included in the meta-analysis. The use of bicycle helmets was found to reduce head injury by 48%, serious head injury by 60%, traumatic brain injury by 53%, face injury by 23%, and the total number of killed or seriously injured cyclists by 34%. Bicycle helmets were not found to have any statistically significant effect on cervical spine injury. There is no indication that the results from bicycle helmet studies are affected by a lack of control for confounding variables, time trend bias or publication bias. The results do not indicate that bicycle helmet effects are different between adult cyclists and children. Bicycle helmet effects may be somewhat larger when bicycle helmet wearing is mandatory than otherwise; however, helmet wearing rates were not found to be related to bicycle helmet effectiveness. It is also likely that bicycle helmets have larger effects among drunk cyclists than among sober cyclists, and larger effects in single bicycle crashes than in collisions with motor vehicles. In summary, the results suggest that wearing a helmet while cycling is highly recommendable, especially in situations with an increased risk of single bicycle crashes, such as on slippery or icy roads.

The lived experience of rescuing people who have driven into floodwater: Understanding challenges and identifying areas for providing support

BACKGROUND

Drowning is a major public health issue, with risk increasing during times of flood. Driving into floodwater is a major risk factor for flood-related drowning and injury, and despite widespread public health campaigns, many people continue to undertake this risky behaviour and require rescue.

PURPOSE

We aimed to identify key challenges faced by emergency services personnel when rescuing those who have driven into floodwater, and to identify strategies for supporting rescuers in this important role.

METHODS

Australian flood rescue operators (N = 8) who had previously rescued a driver who had driven into floodwater participated in semi-structured interviews. Data were analysed using thematic analysis.

RESULTS

Four challenges emerged from their experiences: involvement of untrained personnel; varying information provided by emergency telephone operators; behaviour of drivers complicating the rescue; people sightseeing floods or flood rescues or ignoring closed roads providing rescuers with sources of distraction and frustration.

CONCLUSIONS

We propose five strategies for translating these results into practice, including: training and protocol development for (i) emergency personnel and (ii) telephone operators; (iii) training for rescuers regarding non-compliant rescuees; (iv) educating the public and (v) increasing compliance with closed roads. Current findings provide valuable insights into how rescuers can be supported in performing their roles, and implementation of these strategies has the potential to reduce fatalities occurring due to attempting to drive through floodwater. SO WHAT?: The strategies presented have the potential to reduce the frequency and improve the outcomes of floodwater rescues, aiding in the prevention of injury and death.

The influence of the elements of procedural justice and speed camera enforcement on young novice driver self-reported speeding

Road policing is an important tool used to modify road user behaviour. While other theories, such as deterrence theory, are significant in road policing, there may be a role for using procedural justice as a framework to improve outcomes in common police citizen interactions such as traffic law enforcement. This study, using a sample of 237 young novice drivers, considered how the four elements of procedural justice (voice, neutrality, respect and trustworthiness) were perceived in relation to two forms of speed enforcement: point-to-point (or average) speed and mobile speed cameras. Only neutrality was related to both speed camera types suggesting that it may be possible to influence behaviour by emphasising one or more elements, rather than using all components of procedural justice. This study is important as it indicates that including at least some elements of procedural justice in more automated policing encounters can encourage citizen compliance.

How would increasing seat belt use affect the number of killed or seriously injured light vehicle occupants?

The expected effects of increasing seat belt use on the number of killed or seriously injured (KSI) light vehicle occupants have been estimated for three scenarios of increased seat belt use in Norway, taking into account current seat belt use, the effects of seat belts and differences in crash risk between belted and unbelted drivers. The effects of seat belts on fatality and injury risk were investigated in a meta-analysis that is based on 24 studies from 2000 or later. The results indicate that seat belts reduce both fatal and non-fatal injuries by 60% among front seat occupants and by 44% among rear seat occupants. Both results are statistically significant. Seat belt use among rear seat occupants was additionally found to about halve fatality risk among belted front seat occupants in a meta-analysis that is based on six studies. Based on an analysis of seat belt wearing rates among crash involved and non-crash involved drivers in Norway it is estimated that unbelted drivers have 8.3 times the fatal crash risk and 5.2 times the serious injury crash risk of belted drivers. The large differences in crash risk are likely to be due to other risk factors that are common among unbelted drivers such as drunk driving and speeding. Without taking into account differences in crash risk between belted and unbelted drivers, the estimated effects of increasing seat belt use are likely to be biased. When differences in crash risk are taken into account, it is estimated that the annual numbers of KSI front seat occupants in light vehicles in Norway could be reduced by 11.3% if all vehicles had seat belt reminders (assumed seat belt wearing rate 98.9%), by 17.5% if all light vehicles had seat belt interlocks (assumed seat belt wearing rate 99.7%) and by 19.9% if all front seat occupants of light vehicles were belted. Currently 96.6% of all (non-crash involved) front seat occupants are belted. The effect on KSI per percentage increase of seat belt use increases with increasing initial levels of seat belt use. Had all rear seat occupants been belted, the number of KSI front seat occupants could additionally be reduced by about 0.6%. The reduction of the number of KSI rear seat occupants would be about the same in terms of numbers of prevented KSI.

Safety effects of fixed speed cameras - An empirical Bayes evaluation

The safety effects of 223 fixed speed cameras that were installed between 2000 and 2010 in Norway were investigated in a before-after empirical Bayes study with control for regression to the mean (RTM). Effects of trend, volumes, and speed limit changes are controlled for as well. On road sections between 100m upstream and 1km downstream of the speed cameras a statistically significant reduction of the number of injury crashes by 22% was found. For killed and severely injured (KSI) and on longer road sections none of the results are statistically significant. However, speed cameras that were installed in 2004 or later were found to reduce injury crashes and the number of KSI on road sections from 100m upstream to both 1km and 3km downstream of the speed cameras. Larger effects were found for KSI than for injury crashes and the effects decrease with increasing distance from the speed cameras. At the camera sites (100m up- and down-stream) crash reductions are smaller and non-significant, but highly uncertain and possibly underestimated.

Enforcement avoidance behavior near automated speed enforcement areas in Korean expressways

Automated speed enforcement system (ASES) has been deployed as a safety countermeasure on Korean roadways to reduce speeding-related traffic crashes; information on ASES locations is mandated to be open to the public. However, because drivers are alerted about enforcement via on-board navigation systems and roadside signs, they can avoid enforcement by momentarily reducing their speeds near ASES locations. This enforcement avoidance behavior (EAB) can induce sudden changes in speed near the enforcement locations and thereby increase risk of crash occurrence. In light of this situation, the present study evaluates the effects of ASES on traffic behavior and safety. An analysis of traffic data shows that drivers indeed diminish their speeds near enforcement locations, and accelerate shortly after passing the locations. To investigate how this behavior affects safety performance, this study, by using Empirical Bayes analysis with comparison groups, compares crash occurrences along a certain section before and after the installation of ASES. The comparative analysis shows that overall crash occurrence dropped by 7.6% on average near the enforcement locations, although the reduction was not significant. However, an average 11% non-significant increase in crash occurrence is also observed in the upstream segment, where enforcement is announced to drivers and traffic starts to diminish speed. The findings suggest that the sudden changes in traffic speed induced by EAB substantially negate the benefits of ASES. Therefore, modification of the design of current ASES is required to mitigate EAB and further improve the effectiveness of ASES.