Speed Limit Enforcement Research Articles

Comprehensive framework for speed-zone guidelines

Abstract Speeding is often considered as one of the major reasons of traffic crashes. As a result, State Departments of Transportations (DOTs) receive requests from communities to decrease speed limits in towns along rural highways. Such requests, coupled with the lack of proper manuals, have forced state DOTs to reduce the speed limits. A proper speed-zone manual is required to establish consistent speed zones across a state. This paper reviewed the literature on speed, crashes, enforcement techniques, and speed-zone manuals. A nationwide survey was conducted to identify various factors affecting the decisions of speed zones establishing. This paper identified best practices based on the literature review and expert opinions, and proposed a comprehensive framework for a speed-zone manual. The Nevada DOT traffic engineers were also interviewed during this research to incorporate their opinions in the framework. The framework provided in this paper has six phases. They are; 1) speed-zone identification; 2) speed-limit determination; 3) transition-zone detailed design; 4) speed-zone approval; 5) speed-limit enforcement; and 6) follow-up study. Relevant studies, and manuals corresponding to each phases were presented in this paper. This framework is useful for NDOT, other state DOTs within the U.S., and transportation agencies worldwide that haven't had speed zone manuals currently to develop a proper speed-zone manual.

Vicious or virtuous circles? Exploring the vulnerability of drivers to break low urban speed limits

Levels of support for 20mph limits in Great Britain are consistently high. However, these positive attitudes are not translating into similarly positive behaviour changes in terms of complying with these new speed limits. Recent research from the authors studied the complex relationship between support and compliance, with qualitative findings suggesting that copycat driving could create a ‘vicious circle effect’ that leads to increased levels of non-compliance. However it is also possible that an alternative ‘virtuous circle’ effect may emerge from the high levels of societal support for 20mph limits pressurising drivers to comply with speed limits. In this work the authors investigated these issues and we report on data and analysis of a large scale survey of drivers and residents undertaken in Great Britain. We explain the origins of vicious and virtuous circles in driver behaviour and study the data from the survey, offering an analysis of attitudes and claimed behaviours that has implications for policy-makers and professionals working with low urban speed limits. We discuss the issues for speed limit enforcement, making reference to the public relations ‘battle’ for public opinion. It is concluded that normative compliance, triggered by community and other campaigning, may be the most realistic mechanism for countering the difficulties of government funding in promoting compliance.

Speeding in America

The enforcement of speed limits to improve public safety constitutes one of the most common activities that the police undertake. Yet, fundamental questions exist about whether traditional, officer-initiated enforcement actually deters speeding and whether it does so in a cost-efficient manner. Questions exist, too, about unintended harms associated with traditional enforcement practices, such as racial, ethnic, and socioeconomic class disparities; mistrust of the police; and, more generally, delegitimization of the law and institutions that implement it. This article draws on prior scholarship to critique traditional speed limit enforcement practices and to argue for approaches that may be more effective, minimize unintended harms, and incur fewer costs.

Automated speed enforcement systems to reduce traffic-related injuries: closing the policy implementation gap

In the USA, traffic-related injuries are responsible for over 33 000 deaths each year1 and are the leading cause of death for individuals aged 1–24 years.2 Traffic-related injuries also take...

Drivers’ behavioral responses to combined speed and red light cameras

BackgroundNumerous signalized intersections worldwide have been equipped with enforcement cameras in order to tackle red light running and often also to enforce speed limits. However, various impact evaluation studies of red light cameras (RLCs) showed an increase of rear-end collisions (up to 44%). ObjectiveThe principal objective of this study is to provide a better insight in possible explaining factors for the increase in rear-end collisions that is caused by placing combined speed and red light cameras (SRLCs). MethodReal-world observations and driving simulator-based observations are combined. Video recordings at two signalized intersections where SRLCs were about to be installed are used to analyze rear-end conflicts, interactions and driver behavior in two conditions (i.e., with and without SRLC). Furthermore, one of these intersections was rebuilt in a driving simulator equipped with an eye tracking system. At this location, two test conditions (i.e., SRLC and SRLC with a warning sign) and one control condition (i.e., no SRLC) are examined. The data of 63 participants were used to estimate the risk of rear-end collisions by means of a Monte Carlo Simulation. ResultsThe results of the on-site observation study reveal decreases in the number of red and yellow light violations, a shift (i.e., closer to the stop line) in the dilemma zone and a time headway reduction after the installation of the SRLC. Based on the driving simulator data, the odds of rear-end collisions (compared to the control condition) for the conditions with SRLC and SRLC+warning sign is 6.42 and 4.01, respectively. ConclusionThe real-world and driving simulator observations indicate that the risk of rear-end collisions increases when SRLCs are installed. However, this risk might decrease when a warning sign is placed upstream.

Overt vs. covert speed cameras in combination with delayed vs. immediate feedback to the offender

Speeding is a major problem in road safety because it increases both the probability of accidents and the severity of injuries if an accident occurs. Speed cameras are one of the most common speed enforcement tools. Most of the speed cameras around the world are overt, but there is evidence that this can cause a “kangaroo effect” in driving patterns. One suggested alternative to prevent this kangaroo effect is the use of covert cameras. Another issue relevant to the effect of enforcement countermeasures on speeding is the timing of the fine. There is general agreement on the importance of the immediacy of the punishment, however, in the context of speed limit enforcement, implementing such immediate punishment is difficult. An immediate feedback that mediates the delay between the speed violation and getting a ticket is one possible solution. This study examines combinations of concealment and the timing of the fine in operating speed cameras in order to evaluate the most effective one in terms of enforcing speed limits. Using a driving simulator, the driving performance of the following four experimental groups was tested: (1) overt cameras with delayed feedback, (2) overt cameras with immediate feedback, (3) covert cameras with delayed feedback, and (4) covert cameras with immediate feedback. Each of the 58 participants drove in the same scenario on three different days. The results showed that both median speed and speed variance were higher with overt than with covert cameras. Moreover, implementing a covert camera system along with immediate feedback was more conducive to drivers maintaining steady speeds at the permitted levels from the very beginning. Finally, both ‘overt cameras’ groups exhibit a kangaroo effect throughout the entire experiment. It can be concluded that an implementation strategy consisting of covert speed cameras combined with immediate feedback to the offender is potentially an optimal way to motivate drivers to maintain speeds at the speed limit.

Evaluation Of Major Causes Of Road Accidents Along North–East Highway, Nigeria

A major road link in the North-Eastern region of Nigeria is the Bauchi – Maiduguri highway that is a 425 km road that links a section of the north east region to other regions of Nigeria. The goods and services to the region are basically transported by road. This has increased vehicular traffic that resulted in increased road accident rates over the years. It is paramount to investigate the major causes of vehicle accidents on this highway as much has not been done to investigate accident cases on the route. The five year accident record on that route was obtained from the Federal Road Safety Corp of Nigeria, the Nigeria Police traffic unit, and the Nigeria union of road traffic workers. The study indicated that speed violation by drivers and bad road conditions contributes greatly in the rate of accidents along the route. Hence the study recommends better road maintenance culture and more sensitization of the road users and enforcement of speed limits.

Bicycle Safety

Bicycle Safety

MORTALITY PATTERNS IN ENDANGERED HAWAIIAN GEESE (NENE; BRANTA SANDVICENSIS).

Understanding causes of death can aid management and recovery of endangered bird populations. Toward those ends, we systematically examined 300 carcasses of endangered Hawaiian Geese (Nene; Branta sandvicensis) from Hawaii, Maui, Molokai, and Kauai between 1992 and 2013. The most common cause of death was emaciation, followed by trauma (vehicular strikes and predation), and infectious/inflammatory diseases of which toxoplasmosis (infection with Toxoplasma gondii) predominated. Toxicoses were less common and were dominated by lead poisoning or botulism. For captive birds, inflammatory conditions predominated, whereas emaciation, trauma, and inflammation were common in free-ranging birds. Mortality patterns were similar for males and females. Trauma predominated for adults, whereas emaciation was more common for goslings. Causes of death varied among islands, with trauma dominating on Molokai, emaciation and inflammation on Kauai, emaciation on Hawaii, and inflammation and trauma on Maui. Understanding habitat or genetic-related factors that predispose Nene (particularly goslings) to emaciation might reduce the impact of this finding. In addition, trauma and infection with T. gondii are human-related problems that may be attenuated if effectively managed (e.g., road signs, enforcement of speed limits, feral cat [Felis catus] control). Such management actions might serve to enhance recovery of this endangered species.

Accidents Represent a Major Epidemic of Non Communicable Disease: Enforcement of Laws to Control it

In India, road accidents lead to death and disability as well as financial costs to both society and the individuals involved. Worldwide it was estimated that 1.2 million people were killed (2.2% of all deaths) and 50 million more were injured in motor vehicle collisions. Legislation embodies codified set of rules. These are enforced by the state to prevent accidents. these include driving test, medical fitness to drive, enforcement of speed limits, compulsory wearing of seat belts and rash helmets, checking of blood alcohol concentration, road side breath testing for alcohol, regular inspection of vehicles, periodic re-examination of drivers over the age of 55, etc.

Roundabouts as an Effective Tool of Traffic Management

Driving speed is one of the most important factors in road safety and speed not only affects the severity of a crash, but is also related to the risk of being involved in a crash. Inappropriate speed is responsible for more than a third of all fatal accidents occurring on roads. In Poland every year majority of all traffic accidents occur in urban areas from which most is recorded at junctions and their vicinity. Hence it is of great importance to effectively manage speed and enforce speed limits on existing road network. Replacing already existing three- or four-arm junctions by roundabouts and construction new ones is considered to be a good solution for safety improvements and also are pointed to be within traffic calming features but their effectiveness is influencing by type, shape and geometry of the junction. The aim of this paper is to analyse the effectiveness of chosen traffic calming measures in comparison with the effectiveness of roundabouts. Research area was located in city of Bialystok, Poland and included a group of commonly applied physical measures together with small and mini roundabouts. Measurements of instantaneous speed by utilizing GPS data logger and assessment of the extent impact of selected TCMs on drivers’ manoeuvres were undertaken to develop the investigation. DOI: http://dx.doi.org/10.5755/j01.sace.9.4.7357

Factors affecting injury severity of vehicle occupants following road traffic collisions

AimWe aimed to define factors affecting injury severity of vehicle occupants following road traffic collisions (RTC). Patients and methods422 vehicle occupants (343 males, 81.3%) with RTC-related injuries were prospectively studied over 18 months. General linear model was used to test the effect of age, gender, alcohol and drug use, time of injury, mechanism of injury, size and speed of the vehicle, position in the vehicle, seatbelt usage, and air bag deployment on the Injury Severity Score (ISS) of the vehicle occupants. ResultsThe mean (range) age of patients was 28.2 (1–78) years and the mean (range) ISS was 7.9 (1–50). Front impact was the most common mechanism of injury (32.9%) followed by rollover (25.6%) and side impact (22.3%). 18.2% used seatbelts. The general linear model was highly significant and showed that mechanism of injury (p<0.0001), speed of the vehicle (p=0.02), and age of the vehicle occupant (p=0.03) significantly affected the Injury Severity Score. ConclusionsThe mechanism of the RTC, the vehicle speed, and age of the vehicle occupant are the most important factors affecting the severity of road traffic collision injuries. A detailed history of the mechanism of injury is important for alerting clinicians to severity of injury, the need for admission, and workup of the patients. Furthermore, strict speed limit enforcement is an injury prevention priority in our community.

Automated section speed control on motorways: An evaluation of the effect on driving speed

Automated section speed control is a fairly new traffic safety measure that is increasingly applied to enforce speed limits. The advantage of this enforcement system is the registration of the average speed at an entire section, which would lead to high speed limit compliances and subsequently to a reduction in the vehicle speed variability, increased headway, more homogenised traffic flow and increased traffic capacity. However, the number of studies that analysed these effects are limited. The present study evaluates the speed effect of two section speed control systems in Flanders, Belgium. Both sections are located in the opposite direction of a three-lane motorway with a posted speed limit of 120km/h. Speed data were collected at different points: from 6km before the entrance of the section to 6km downstream from the section. The effect was analysed through a before- and after comparison of travel speeds. General time trends and fluctuations were controlled through the analysis of speeds at comparison locations. On the enforced sections considerable decreases were found of about 5.84km/h in the average speed, 74% in the odds of drivers exceeding the speed limit and 86% in the odds of drivers exceeding the speed limit by more than 10%. At the locations up- and downstream from the section also favourable effects were found for the three outcomes. Furthermore a decrease in the speed variability could be observed at all these data points.

Demonstrating a Correlation Between the Maturity of Road Safety Practices and Road Safety Incidents

Objective: The objective of this study is to demonstrate a correlation between the maturity of a country's road safety practices and road safety incidents.Methods: Firstly, data on a number of road injuries and fatalities for 129 countries were extracted from the United Nations Global Status on Road Safety database. These data were subdivided according to road safety incident and accident causation factors and normalized based on vehicular fleet (per 1000 vehicles) and road network (per meter of paved road). Secondly, a road safety maturity model was developed based on an adaptation of the concept of process maturity modeling. The maturity of countries with respect to 10 road safety practices was determined through the identification of indicators recorded in the United Nations Global Status of Road Safety Database. Plots of normalized road safety performance of the 129 countries against their maturity scores for each road safety practice as well as an aggregation of the road safety practices were developed. An analysis of variance was done to determine the extent of the correlation between the road safety maturity of the countries and their performance. In addition, a full Bayesian analysis was done to confirm the correlation of each of the road safety practices with injuries and fatalities.Results: Regression analysis for fatalities, injuries, and combined accidents identified maturity with respect to road safety practices associated with speed limits and use of alternative modes as being the most significant predictors of traffic fatalities. A full Bayesian regression confirms that there is a correlation between the maturity of road safety practices and road safety incidents.Conclusion: Road safety practices associated with enforcement of speed limits and promotion of alternative modes are the most significant road safety practices toward which mature countries have concentrated their efforts, resulting in a lower frequency of fatalities, injury rates, and property damage accidents. The authors argue that the use of gross domestic product (GDP) as a predictor of road safety incidents suffers from the presumptive assumption that the only criterion that matters is national income, therefore erroneously predicting that richer countries all perform approximately the same in fatalities and that developing nations are at various stages, with high variability and uncertainty in prediction. It is proposed that an aggregation of individual maturity scores from road safety practices will lead to a better indicator for policy because it connects externalities (fatalities/injuries) with intrinsic factors for which policies can be oriented.

Speeding in school zones: violation or lapse in prospective memory?

Inappropriate speed is a causal factor in around one third of fatal accidents (OECD/ECMT, 2006). But are drivers always consciously responsible for their speeding behavior? Two studies are reported which show that an interruption to a journey, caused by stopping at a red traffic light, can result in failure to resume the speed of travel prior to the interruption (Study 1). In Study 2 we showed that the addition of a reminder cue could offset this interruption. These studies were conducted in a number of Australian school zone sites subject to a 40 km/h speed limit, requiring a reduction of between 20 km/h and 40 km/h. Motorists who had stopped at a red traffic signal sped on average, 8.27 km/h over the speed limit compared with only 1.76 km/h over the limit for those who had not been required to stop. In the second study a flashing "check speed" reminder cue, placed 70 m after the traffic lights, in the same school zones as those in Study 1 eliminated the interruptive effect of stopping with drivers resuming their journey at the legal speed. These findings have practical implications for the design of road environments, enforcement of speed limits, and the safety of pedestrians.

Highway Accident Modeling and Forecasting in Winter

Environmental attributes are critical risk factors that have proven to affect collision rates. Associated driving risks can be reduced by better maintenance of roadway infrastructure, enforcement of speed limits or other traffic laws. Given the preventive nature of these policies and regulations, accurate predictions of environmental attributes are needed. Currently, most of road safety prediction models are based on deterministic weather forecasts which are not able to capture changes in the likelihood of collision occurrence. As a result, probabilistic forecast is required to improve decision making, mainly in winter. In this paper, a stochastic approach to modeling highway collisions in winter time is considered which enables better assessment of driving conditions and a more accurate prediction. A logistic regression model with covariates is applied to crash data where environmental characteristics are modeled as a finite state space homogeneous multivariate discrete time Markov chain. After fitting the model, weather prediction as well as the conditional predictive probability distribution of collision occurrence are obtained. As the application, the ability of the proposed model to predict hourly environmental attributes and collision occurrence is examined using real highway crash data. The performance of the developed stochastic model is compared with several existing models in the literature using actual collision data. The results demonstrate that the proposed stochastic model outperforms existing models and it accurately predicts collision occurrence in the presence of stochastically changeable winter weather conditions. As a result, the proposed probabilistic forecast model can be used as a valuable tool in a decision support system.

실제 선로조건에서의 레일 경좌 변화에 따른 철도차량의 주행안전성 해석

Railways are currently subject to the enforcement of speed limits for each curve as prescribed by the Railway Operating Rules in Korea. However, research is required to determine the maximum speed of trains passing through each curve that allows them to run without the risk of derailment in relation to the speed enhancement of existing railway tracks. In addition, factors affecting the running safety of railway vehicles can be classified into those in terms of vehicle aspects and those in terms of track aspects. This study sought to analyze the running safety of railway vehicles according to changes in the inclination of the rail from among the factors affecting the enhancement of safety against derailment. To increase the speed of trains passing through curves that have high derailment risk, this study also analyzed the running safety of railway vehicles according to the inclination of the rail and changes in running speed while a vehicle passes through each curve section in both the up and the down train line sections between Namsunghyun and Chungdo, which represent the actual conditions of railway tracks.

The impacts of speed cameras on road accidents: An application of propensity score matching methods

This paper aims to evaluate the impacts of speed limit enforcement cameras on reducing road accidents in the UK by accounting for both confounding factors and the selection of proper reference groups. The propensity score matching (PSM) method is employed to do this. A naïve before and after approach and the empirical Bayes (EB) method are compared with the PSM method. A total of 771 sites and 4787 sites for the treatment and the potential reference groups respectively are observed for a period of 9 years in England. Both the PSM and the EB methods show similar results that there are significant reductions in the number of accidents of all severities at speed camera sites. It is suggested that the propensity score can be used as the criteria for selecting the reference group in before-after control studies. Speed cameras were found to be most effective in reducing accidents up to 200 meters from camera sites and no evidence of accident migration was found.

Speed management strategies and drivers' attitudes in Thailand

In Thailand where speeding on highways and roads has been a key contributing factor in road traffic crashes, considerable efforts to control vehicle speeds have been made, mostly through speed limit enforcement. However, the fact that speed limits are very often violated on a large scale in Thailand suggests the need for implementing more effective speed management strategies such as automatic speed cameras, increasing speeding penalty, and smart vehicle design to control vehicle speeds. While the effectiveness of such measures depends mainly on how well they could lead drivers to change speeding behavior, public acceptability is also vital as a key to sustainability of most speed management programs. This paper attempts to identify public acceptability of speed management measures, both currently implemented and under consideration, in Thailand. In doing so, data from the questionnaire surveys based on a random sample of 2180 drivers in Thailand including a wide range of individual characteristics of respondents and their attitudes to select speed management schemes are analyzed using an econometric technique. In particular, we introduce a simplified methodological framework to develop a better understanding of factors that explain drivers' attitudes towards speeding behavior and alternative speed management strategies. Findings from this research provide several important implications that could improve the current practices of speed management in Thailand.

Burden and risk factors for road traffic injuries in two districts of Kenya: a descriptive analysis

BackgroundA combination of increasing vehicle volume on the road, evolving mix of vehicles, poor infrastructure, and unsafe vehicles has led to increasing road traffic crashes, injuries and fatalities in Kenya.Aims/Objectives/PurposeThis...