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.
Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Heloisa
H
Barbosa
Universidade Federal do Ceará, Fortaleza, Brazil. Electronic address: flaviocunto@det.ufc.br.
Flávio
F
Cunto
Universidade Estadual Paulista, Bauru, Brazil.
Bárbara
B
Bezerra
Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Christine
C
Nodari
Universidade de Brasília, Brasília, Brazil.
Maria Alice
MA
Jacques
D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D001938:Brazil; D002138:Calibration; D002947:Cities; D004779:Environment Design; D006801:Humans; D015233:Models, Statistical; D012449:Safety / Q000706:statistics & numerical data*
Generalized Estimating Equations; Generalized linear models; Observational road safety studies; Road safety; Safety performance models