Title
Geographical Unit Based Analysis In The Context Of Transportation Safety Planning
Keywords
Bayesian Poisson log-normal model; Macro-level analysis; Traffic analysis zones; Transportation safety planning
Abstract
A wide array of spatial units has been explored in macro-level modeling. With the advancement of Geographic Information System (GIS) analysts are able to analyze crashes for various geographical units. However, a clear guideline on which geographic entity should be chosen is not present. Macro level safety analysis is at the core of transportation safety planning (TSP) which in turn is a key in many aspects of policy and decision making of safety investments. The preference of spatial unit can vary with the dependent variable of the model. Or, for a specific dependent variable, models may be invariant to multiple spatial units by producing a similar goodness-of-fits. In this study three different crash models were investigated for traffic analysis zones (TAZs), block groups (BGs) and census tracts (CTs) of two counties in Florida. The models were developed for the total crashes, severe crashes and pedestrian crashes in this region. The primary objective of the study was to explore and investigate the effect of zonal variation (scale and zoning) on these specific types of crash models. These models were developed based on various roadway characteristics and census variables (e.g., land use, socio-economic, etc.). It was found that the significance of explanatory variables is not consistent among models based on different zoning systems. Although the difference in variable significance across geographic units was found, the results also show that the sign of the coefficients are reasonable and explainable in all models. Key findings of this study are, first, signs of coefficients are consistent if these variables are significant in models with same response variables, even if geographic units are different. Second, the number of significant variables is affected by response variables and also geographic units. Admittedly, TAZs are now the only traffic related zone system, thus TAZs are being widely used by transportation planners and frequently utilized in research related to macroscopic crash analysis. Nevertheless, considering that TAZs are not delineated for traffic crash analysis but they were designed for the long range transportation plans, TAZs might not be the optimal zone system for traffic crash modeling at the macroscopic level. Therefore, it recommended that other zone systems be explored for crash analysis as well. © 2013 Elsevier Ltd.
Publication Date
1-1-2013
Publication Title
Transportation Research Part A: Policy and Practice
Volume
49
Number of Pages
62-75
Document Type
Article
Personal Identifier
scopus
DOI Link
https://doi.org/10.1016/j.tra.2013.01.030
Copyright Status
Unknown
Socpus ID
84873963669 (Scopus)
Source API URL
https://api.elsevier.com/content/abstract/scopus_id/84873963669
STARS Citation
Abdel-Aty, Mohamed; Lee, Jaeyoung; Siddiqui, Chowdhury; and Choi, Keechoo, "Geographical Unit Based Analysis In The Context Of Transportation Safety Planning" (2013). Scopus Export 2010-2014. 7844.
https://stars.library.ucf.edu/scopus2010/7844