Neste trabalho é avaliado o impacto do emprego de radares fixos na velocidade e na acidentalidade no trecho compreendido entre o Km 153,350 e o Km 227,800 da Rodovia Washington Luís - SP-310 (extensão de 74,450 km), localizado no interior do estado de São Paulo e cuja concessão pertence à empresa Centrovias. A avaliação do impacto na velocidade e na acidentalidade foi realizada em segmentos curtos situados no entorno dos radares e em toda a extensão do trecho. As medições de velocidade foram realizadas nos pontos onde se localizam os radares fixos, em pontos próximos (cerca de 2km antes e 2km depois) e em pontos distantes. Os resultados mostram que o limite legal de velocidade é mais respeitado no local onde se localizam os radares e um pouco antes dos mesmos. Logo depois dos radares e em pontos distantes, o limite máximo de velocidade é muito menos respeitado. É muito alta a porcentagem de veículos que passam pelos radares com velocidade acima do limite legal mais a tolerância de 7km/h (8,4%), e que, portanto, cometem infração e deveriam ser multados. Claramente, a abrangência espacial dos radares fixos no sentido de reduzir as velocidades é limitada a um pequeno segmento localizado, na sua maior parte, imediatamente antes dos mesmos. A evolução dos índices de acidentes mostra que não houve melhoria na segurança com a colocação dos radares nos segmentos localizados no entorno dos mesmos. Praticamente todos os índices apresentaram crescimento. Isso também acontece quando se analisa a evolução dos índices de acidentes ao longo de toda a extensão do trecho de rodovia estudado, pois todos os índices experimentaram crescimento / In this work the impact of the use of fixed radars in the speed and in the analysis of accidents in the segment between the Km 153,350 and the km 227,800 of the Washington Luís Highway is evaluated - SP-310 (extension of 74,450 km), located in the interior of the state of São Paulo and whose concession belongs to the Centrovias company. The evaluation of the impact in the speed and in the analysis of accidents was carried out in short segments situated around of the radars and in all the extension of the segment. The measurements of speed had been done in the points where the fixed radars were located, in points near (about of 2km before and 2km after) and in distant points. The results show that the legal limit of speed is more respected in the place where the radars are located and just before them. Soon after the radars and in distant points, the maximum limit of speed is much less respected. The percentage of vehicles that pass by the radars with speed above of the legal limit plus the tolerance of 7km/h (8,4%), is very high, resulting in infraction that should be fined. Clearly, the use of the fixed radars intending to reduce the speeds is limited to a small segment located, normally immediately before them. The evolution of the indices of accidents shows that did not have improvement in the security using radars in the segments located near them. Practically all the indices had presented growth. This also happens when it is analyzed the evolution of the indices of accidents in all the extension of the studied segment of highway, because all the indices had growth

As the movement to decriminalize marijuana has gained more support throughout the United States, as of early 2017, 21 states have decriminalized the possession of a small amount of marijuana for personal recreational use, and more states are expected to decriminalize marijuana (GOVERNING 2017). Despite this strong move toward decriminalizing marijuana, however, the consequences of implementing such a policy are still very much unknown. One of the concerns regarding this movement to decriminalize marijuana is its potential impact on road safety (Schrader 2015; Roberts 2017; Halsey 2015). Although there are a few studies that have examined the association between marijuana use and availability and traffic fatalities, these studies are correlational in nature and show divergent outcomes (Anderson and Ree 2011; Anderson et al. 2013). Furthermore, these studies do not examine the impact of decriminalizing marijuana on road safety. In order to fill this gap, my research investigates the causal association between marijuana decriminalization and traffic fatalities by using the synthetic control method, pioneered by Abadie et al. (2010). This study estimates the causal effects of 2009 Massachusetts's marijuana decriminalization on Massachusetts' total traffic fatalities by comparing Massachusetts's trends in total traffic fatalities and its synthetic counterpart. The results of this study show a temporary increase in the number of total traffic fatalities in Massachusetts compared to its synthetic counterpart between 2009 and 2012, suggesting marijuana decriminalization's detrimental effect on road safety. Future studies should consider investigating the heterogeneous effects of marijuana decriminalization on traffic fatalities based on age groups, gender, and residential density and the causal mechanism between marijuana decriminalization and traffic fatalities.

In reconstruction of on-roadway vehicle accidents, roadway surface gouges and the forces and energy attributed to the related vehicle components become important keys to resolving an accurate accident reconstruction. These roadway gouge forces vary depending upon such factors as surface temperature and the velocity and geometry of the gouging mechanism. Accounting for the forces applied to vehicle components and the energy dissipated from such forces can be helpful in accident reconstruction where supporting data exists. This research documents the force necessary to create a given roadway gouge geometry. Controlled pavement gouging tests were performed using roadway surface temperature and gouging velocity as main factors. The results of this testing and analysis are useful in quantifying gouge forces and energies for use in accident reconstruction. The findings show that the temperature of the roadway surface that is being damaged significantly affects the amount of force required to cause the damage. A summary of experiments and techniques as applied to accident reconstruction are presented.

El sistema de señalización vial horizontal para carretera convencional es uno de los elementos del equipamiento viario que guarda mayor relación con la seguridad vial. Por ello, la investigación de nuevos materiales y sistemas de aplicación que contribuyan a la mejora de los parámetros físico-ópticos de las marcas viales es vital para el aumento del nivel de servicio de la carretera y, además, para colaborar en la disminución de la siniestralidad en carretera. Por tal motivo, en la presente tesis doctoral se han estudiado las características esenciales de las marcas viales: visibilidad diurna, visibilidad nocturna, resistencia al deslizamiento y durabilidad en busca de la óptima señalización vial horizontal en carretera convencional. Para ello se han desarrollado tres estudios de investigación en tres campos de prueba ejecutados in-situ en distintas carreteras convencionales. En cada uno de ellos se ha evaluado y se han extraído conclusiones que nos han permitido seguir avanzando en la misma línea de investigación a través de los siguientes estudios. En el primer estudio llevado a cabo, se analizaron 81 combinaciones de materiales, aplicadas en el campo de pruebas in-situ nº 1 localizado en la CV-9006 con tipología de travesía, variando el tipo de material base, el material de post-mezclado, sus dosificaciones y los sistemas de aplicación. Para ello se estudiaron los dos parámetros fundamentales: factor de luminancia β y la retrorreflexión RL en seco, para las probetas recién aplicadas, al mes y a los seis meses de antigüedad. Para el segundo estudio se utilizaron materiales y sistemas de aplicación nuevos consiguiendo 14 probetas en cada sentido de circulación, que forman un total de 28 probetas. Éstas fueron ejecutadas in-situ en la CV-8354 y se analizaron los parámetros esenciales de las marcas viales: factor de luminancia β, retrorreflexión RL en seco y coeficiente de rozamiento SRT. El tercer estudio se compuso de 18 combinaciones de materiales para cada sentido de circulación, con un total de 36 probetas, en el campo de pruebas nº 3 de la carretera CV-904. En este caso, los parámetros característicos analizados de las probetas fueron: factor de luminancia β, coordenadas cromáticas (x,y), coeficiente de luminancia en iluminación difusa Qd, retrorreflexión RL en seco, retrorreflexión RL en húmedo y coeficiente de rozamiento SRT para las 36 probetas recién aplicadas, al mes, a los 6 meses, a los 12 meses y a los 18 meses desde su fabricación. Finalmente, tras el análisis cuantitativo y cualitativo de todos los parámetros fotométricos que caracterizan las marcas viales, se ha conseguido establecer el sistema de señalización vial horizontal óptimo para carretera convencional y sus pautas de comportamiento a lo largo del tiempo.

The Gambia is the smallest country in mainland Africa. Along with the rapid urbanization rate, motorization has increased rapidly as well, contributing to an increased number of road traffic crashes. Road traffic crashes are the 4th leading cause of in-patient deaths in adults in the Gambia and currently are a significant public health problem. This study utilized the Gambia Traffic Force’s data registry to become the first epidemiological study on road traffic injuries in the Gambia as well as the first to analyze the Gambia’s traffic data registry on a national level. Reported crashes from October 1st, 2014 to June 30, 2015 were converted from the paper-based data registry into an electronic database and analyzed statistically, and the location data were geocoded and plotted on the Gambian map. The results of this study showed that crashes involving pedestrian victims and crashes that occurred on unpaved roads were more likely to be associated with outcomes that were fatal or serious. When multiple vehicles were involved in a crash, the involvement of motorcycles and bicycles were more likely to lead to a fatal or serious injury. The mapped data showed that towards the center of each district, the number of crashes increased as pedestrian and vehicle density increased, but that injury severity outcomes were generally minor or none. In contrast, as pedestrian and vehicle density decreased, crash frequency decreased as well, but injury outcomes were more likely to be severe or fatal. The findings of the study also helped in identifying areas in policy and education that need improvement.

The research presented in this thesis is the result of field data collection conducted by the Utah Local Technical Assistance Program (Utah LTAP) in conjunction with the Utah Department of Transportation. The first step of the research was data collection from 18 road safety audits conducted throughout the state of Utah. These Road Safety Audits (RSA's) provided a wide variety of data that was used for the validation of the road safety audit quantification methodology. The purpose of this research is to provide quantification to the RSA process that will increase the benefits gained from implementing the RSA recommendations. Benefits derived from the implementation of RSA recommendations were found by assessing the change of risk from before and after safety improvements. The RSA quantification tool was developed to analyze projects in both urban and rural settings. The implementation of the RSA tool will help practitioners show the benefits that can be gained from the safety recommendations and help decision makers in allocating funds to the areas that pose the most risk. The tool will show the difference in risk that the improvements make and the cost effectiveness of different project alternatives.

Child road trauma poses a preventable public health burden to the community. This PhD research aimed to: 1) quantify the magnitude of child passenger injuries in New South Wales (NSW), Australia; 2) evaluate the effectiveness of different restraint use to prevent fatalities among child passengers; and 3) estimate the benefit in the general child population from different intervention targets relating to restraint use. It comprised two studies to validate methodology and four independent epidemiological studies. The first study to validate methodology assessed the data item availability and categorization across different road traffic injury surveillance data collections in NSW in relation to World Health Organization recommended data item lists and necessary data item lists for road traffic injury research. Exclusion of, or insufficient categorization of, crucial data items such as restraint use and injurious outcome existed for each data collection. The other study to validate methodology assessed the performance (in terms of incidence estimates, sensitivity, and specificity) of several methods for removing multiple counting when conducting analyses on hospital separation data for child passenger injuries under either primary-diagnosis or all-diagnoses based injury definition, using linkage methods as a comparison. The "readmission"-based criterion consistently best approximated the linkage-method-derived incidence rate. Two epidemiological studies used NSW hospital separation datasets and quantified the magnitude of child road trauma in NSW in terms of hospitalisation rates. One study examined the trend in hospitalised injury incidence rates during the period of July 1998 to June 2005 using a non-parametric estimation method, and reported a non-significant decline of hospitalised injuries to child passengers over time. The second study used Poisson regression to demonstrate that rural NSW children were two times more likely to suffer hospitalised injuries compared with their urban counterparts. The third epidemiological study used the Fatality Analysis Reporting Systems (FARS) from the United States (US) and estimated the association between different restraint uses and child passenger fatality using a matched cohort method. Improperly using restraints significantly elevated the risk of death for child passengers involved in a crash compared to any other restraint use. The advantage of child restraints over seat belts in terms of fatality reduction was not statistically significant, although previous studies have shown an advantage for serious injury reduction. The last study was performed to quantify the relative public health benefit in terms of reduction in child passenger deaths and injuries for different interventions relating to restraint use in the general population using a case-based population attributable risk fraction method. Results support the ongoing child restraint legislation change in Australia to require compulsory child restraint uses for children up to their 7th birthday, and an increasing proper use of age-appropriate restraints would provide the greatest reduction in fatalities and injuries among child passengers assuming equal population uptake for all interventions. In conclusion, this thesis demonstrates that child road trauma remains a public health burden to the Australian community; and highlights the importance of properly using age-appropriate restraints in preventing injuries to child passengers.

Accurate assessment of road luminance provided by overhead streetlights helps to optimize the visibility of objects on the road and therefore promotes driver safety, while minimizing energy consumption. To calculate road luminance, the road surface reflectivity has to be known. Odyssey Energy Limited has developed a prototype system that has the potential to determine the road reflectivity properties at high speed. In this thesis, an investigation into the prototype system has been conducted and further enhancement and redesign has been done. A portable on-site road surface reflectivity measurement system that complies with the Commission Internationale de I' Eclairage (CIE) standard was developed. The road test of this new system has been carried out on a series of Hamilton city roads. It proved that the new system is capable of measuring the road surface reflectivity and classifying the road into its appropriate R class according to the CIE standards specified in street lighting design criteria. Later the OEL prototype system was calibrated against the new system to find out the correlation between the two systems.

The problem surrounding the ever-increasing toll of death and injury arising from road accidents is one which is receiving increasing attention as the number of vehicles on the road continues to rise. While it has not been possible to isolate any one factor as the sole or even primary cause of road accidents, several surveys have shown that in many accidents alcohol has been a contributory factor by affecting the faculties of the driver of pedestrian. The thesis then goes on to discuss factors causing individual differences in response to the same blood alcohol concentration and the correlation between impairment of driving and blood alcohol concentration.

Cross-country (XC) mountain bike (MTB) riding is a new cycling discipline and research examining the physiological demands of MTB racing is limited. The purpose of this study was to comprehensively measure physiological characteristics, to identify the performance demands of XC and time trial (TT) MTB racing and to simulate a field MTB race in the laboratory to measure the physiological responses associated with racing. Twelve male and four female elite MTB cyclists volunteered to take part in this study. Subjects completed maximal aerobic power and, anaerobic power and capacity tests. MTB race data was collected during TT and XC competitions with SRM MTB power cranks fitted to the subjects MTB. Five male MTB cyclists (V . O2max 72.0 +/- 4.6 ml/kg/min-1, maximum power output (MPO) 5.40 +/- 0.30 W/kg-1, maximum heart rate (HRmax) 189 +/- 7 bpm) performed two laps of a MTB course in the field using their race bikes with MTB SRM power cranks fitted. A laboratory MTB race simulation was performed using a wind braked ergometer. Cyclists attempted to match the average and peak power output (W/kg-1) achieved in the field trial in the laboratory. Power output (PO), heart rate (HR) and cadence (revolutions per minute, rpm) were measured during field and laboratory trials, while oxygen uptake (V . O2) was determined only during the laboratory simulation. Results showed TT MTB racing is significantly shorter in duration and distance than XC racing and significantly higher for power output and heart rate, with more time spent above anaerobic threshold (16.0 +/- 2.4 and 22.8 +/- 4.3% time) and MPO (38.4 +/- 5.2 and 26.5 +/- 9.4% time) than XC racing (p<0.05). Mean power output and heart rate between the field and laboratory trials were similar (4.18 +/- 0.55 and 4.17 +/- 0.15 W/kg-1 respectively, 175 +/- 9 and 170 +/- 8 bpm). Time spent below 2 W/kg-1 and above 6 W/kg-1 for the field and laboratory trials accounted for ~32% and ~30% of the total time, respectively. During field and laboratory trials, cyclists utilised 77.8 and 77.3% of MPO, 93 and 90% of HRmax, respectively. There was a significant difference between mean cadence in the field and laboratory trials (60.3 +/- 9.1 and 75.2 +/- 7.0 rpm, respectively, p<0.05). The cadence band of 60-69 rpm showed a significant difference between the time spent in that band from the field (14.6%) to the laboratory (4.6%). The time spent above a cadence of 80 rpm in the field was 29.8% compared to the laboratory at 62.0% of the time. Mean and peak V . O2 for the simulation was 57.5 +/- 3.3 and 69.3 +/- 4.4 ml/kg-1/min-1 respectively, with cyclists sustaining an average of ~80% V . O2max. In summary, MTB competition requires multiple short-high intensity efforts and places high demands on both the aerobic and anaerobic energy systems. The power output and heart rate responses to a MTB field race are similar when simulated in the laboratory, although in the laboratory higher cadences are selected for the higher power outputs than the field.