Flávio José Craveiro Cunto

An Analysis of the Injury Severity of Motorcycle Crashes in Brazil Using Mixed Ordered Response Models

ABSTRACT The Brazilian traffic environment has experienced a disproportionate growth in motorcycle use over the last 15 years. Unfortunately the same trend has been observed for crash frequency and severity in the category in part by their relative exposure as well as vulnerability. This study investigates factors that influence the severity of motorcycle accidents in urban streets of Fortaleza. Traditional and mixed ordered logit models were calibrated using a sample of 3,232 observations of traffic accidents from 2004 to 2011. Physical levels of injury inflicted to motorcyclists were grouped as no apparent injury, slight injury, serious injury, and fatal injury. The models were developed using several variables as risk factors. Results suggested that motorcyclists using helmets reduced their chances by 9% of suffering severe and fatal injuries after the crash. Accidents during the daylight as well as on weekdays presented lower risk of resulting in fatal injuries. Also, crashes involving motorcyclists older than age 61 years have 22% more probability of resulting in severe and fatal injuries as compared to young riders. Most of these findings can be associated with commonly reported risky behavior from motorcyclists such as speeding, improper lane changes, and red light running.

Geographically weighted negative binomial regression applied to zonal level safety performance models

Generalized Linear Models (GLM) with negative binomial distribution for errors, have been widely used to estimate safety at the level of transportation planning. The limited ability of this technique to take spatial effects into account can be overcome through the use of local models from spatial regression techniques, such as Geographically Weighted Poisson Regression (GWPR). Although GWPR is a system that deals with spatial dependency and heterogeneity and has already been used in some road safety studies at the planning level, it fails to account for the possible overdispersion that can be found in the observations on road-traffic crashes. Two approaches were adopted for the Geographically Weighted Negative Binomial Regression (GWNBR) model to allow discrete data to be modeled in a non-stationary form and to take note of the overdispersion of the data: the first examines the constant overdispersion for all the traffic zones and the second includes the variable for each spatial unit. This research conducts a comparative analysis between non-spatial global crash prediction models and spatial local GWPR and GWNBR at the level of traffic zones in Fortaleza/Brazil. A geographic database of 126 traffic zones was compiled from the available data on exposure, network characteristics, socioeconomic factors and land use. The models were calibrated by using the frequency of injury crashes as a dependent variable and the results showed that GWPR and GWNBR achieved a better performance than GLM for the average residuals and likelihood as well as reducing the spatial autocorrelation of the residuals, and the GWNBR model was more able to capture the spatial heterogeneity of the crash frequency.

Safety performance models for urban intersections in Brazil

This paper presents a modeling effort for developing safety performance models (SPM) for urban intersections for three major Brazilian cities. The proposed methodology for calibrating SPM has been divided into the following steps: defining the safety study objective, choosing predictive variables and sample size, data acquisition, defining model expression and model parameters and model evaluation. Among the predictive variables explored in the calibration phase were exposure variables (AADT), number of lanes, number of approaches and central median status. SPMs were obtained for three cities: Fortaleza, Belo Horizonte and Brasília. The SPM developed for signalized intersections in Fortaleza and Belo Horizonte had the same structure and the most significant independent variables, which were AADT entering the intersection and number of lanes, and in addition, the coefficient of the best models were in the same range of values. For Brasília, because of the sample size, the signalized and unsignalized intersections were grouped, and the AADT was split in minor and major approaches, which were the most significant variables. This paper also evaluated SPM transferability to other jurisdiction. The SPM for signalized intersections from Fortaleza and Belo Horizonte have been recalibrated (in terms of the Cx) to the city of Porto Alegre. The models were adjusted following the Highway Safety Manual (HSM) calibration procedure and yielded Cx of 0.65 and 2.06 for Fortaleza and Belo Horizonte SPM respectively. This paper showed the experience and future challenges toward the initiatives on development of SPMs in Brazil, that can serve as a guide for other countries that are in the same stage in this subject.

PW 1092 Prevalence of behavioral risk factors for road traffic injuries in three south american cities

Road traffic injuries (RTIs) are an important cause of death and injury in Colombia and Brazil. This burden is not uniform across countries and cities. Understanding these differences and similarities in road traffic behaviors is key in designing effective RTI interventions. This study is aimed to assess such differences by comparing observed road safety behaviors in three South American cities, Bogotá (Colombia), and São Paulo and Fortaleza (Brazil). As part of the Bloomberg Initiative for Global Road Safety (BIGRS), observational studies were conducted in Bogotá, Fortaleza, and São Paulo. Trained observers recorded road safety behavior (speeding, helmet use, seatbelt use and drink driving) every six months between August 2015 and September 2017. Around 1.5 million observations in these risk factors have been collected throughout six rounds of data collection. It was found that Bogotá and São Paulo had varying rates of speeding, very dependent on changes in policy and enforcement circumstances, whereas Fortaleza maintained relatively high and stables rates. Rates of seatbelt and correct helmet use among all passengers were higher in São Paulo than Bogotá and Fortaleza. Drink driving prevalence was higher in Sao Paulo than Fortaleza and Bogotá. Fortaleza has experienced a reducing trend in drink driving prevalence throughout the project. In São Paulo, refusal rates reached 76%. Important regional differences in road safety risk factors highlight the need for tailored interventions in South American cities. Speeding is a priority for Bogotá and Fortaleza. São Paulo’s alcohol results illustrate the urgency for drink driving-based interventions and correct helmet use is an increasingly important need in Bogotá and Fortaleza. These results are being used to develop specific interventions for BIGRS. These results are of interest for policy makers in Latin American cities and other middle-income countries where these interventions can be piloted and if effective, scaled up and replicated.

642 Prevalence of behavioural risk factors for road traffic injuries: regional differences in Brazil

Background Road traffic injuries (RTIs) are estimated to be the fourth leading cause of death in Brazil. This burden is not uniform throughout the country with differences between the wealthy developed South and less-developed North. Understanding regional differences in specific behaviours (speeding, helmet use, seatbelt use and drink driving) associated with RTIs is critical in designing effective RTI interventions. This study aimed to assess such differences by comparing observed road safety behaviours in the cities of Sao Paulo (South) and Fortaleza (North). Methods As part of the Bloomberg Initiative for Global Road Safety (BIGRS), observational studies were conducted in Sao Paulo and Fortaleza, Brazil. Six sites were randomly selected in each city and trained observers recorded road safety behaviour (speeding, helmet use, seatbelt use and drink driving) for three full-day periods between August–October 2015. Results 190,730 observations were collected: Sao Paulo (113,539), Fortaleza (77,191). Fortaleza had higher rates of speeding (16.7%) with motorcycles being the most common speeders compared to Sao Paulo (8.1%) where sedans were most responsible. Rates of seatbelt and helmet use among all passengers were higher in Sao Paulo (90.2% and 99.1%, respectively) than Fortaleza (63.4% and 82.8%, respectively). Drivers testing positive for any alcohol was higher in Sao Paulo (14%) than Fortaleza (1.2%). Conclusions Important regional differences in road safety behaviour highlight the need for tailored interventions in Brazil. National-level interventions might not be as effective as regional ones. While both cities had high rates of helmet use, seatbelt use remains low in Fortaleza. Speeding, especially among motorcycles, is a priority for Fortaleza and parts of Northern Brazil. Sao Paulo’s alcohol results illustrate the urgency for drink driving-based interventions for areas of Southern Brazil. These results will be used to develop specific interventions for BIGRS.

Assessing the Transferability of the Highway Safety Manual Predictive Method for Urban Roads in Fortaleza City, Brazil

AbstractAASHTO’s Highway Safety Manual (HSM) provides guidance to safety professionals and is becoming a standard of practice, particularly for regions that require urgent action because of persistently high crash frequencies that have resulted from an overall lack of safety investments. Differences in crash data systems, local enforcement, driving behavior, and other factors have prompted studies assessing the international transferability of the HSM predictive method. The recent increase in crash occurrences in Brazilian urban areas and the World Health Organization (WHO) Decade of Action for Road Safety initiative have motivated a nationwide joint safety research effort. One of the fundamental questions in this project is related to the applicability of HSM safety performance functions (SPFs) for the Brazilian urban environment. This paper presents the initial results regarding the transferability of the HSM SPFs for estimating the expected average crash frequency of urban intersections in Fortaleza Ci...