# Effect of Built Environment Factors on Pedestrian Safety in Portuguese Urban Areas
## 3 Materials and Methods
### Definition of the Variables  
After carrying out a broad literature review in the field of pedestrian safety, the present study identified three groups of independent variables, in addition to those related to the characteristics of the traffic: built environment, pedestrian infrastructure, and road infrastructure. Table 2 shows these variables along with the dependent variable: the number of annual pedestrian crashes for the GEE model and the corresponding aggregated number for the ZTNB model. Figure 2: Principal steps of the method. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Category** & **Variable** & **Description** & **Mean** & **Std. Dev.** & **Min** & **Max** \\ \hline  & & 1.125 & 1.283 & 0 & 6 \\ Dependent & Y & Number of pedestrian crashes for GEE model & & & \\  & and ZTNB model & & & & \\  & ROAD\_L & Roadway length (m) & 496.4 & 287.322 & 68 & 1317 \\ Built & LU & Land wave & & & & \\ environment & LU & (Mixture = 1, Residual = 0) & & & \\  & PARKS & On-street parking places & & & & \\  & BUS & Bus stops (Yes = 1, No = 0) & & & \\  & NET\_C & Pedestrian network continuity & & & & \\  & NET\_C & (Yes = 1, No = 0) & & & \\ Pedestrian & SIDEMWALK & Sidewalk unobstructed with (m) & 1.233 & 0.649 & 0 & 3 \\ Infrastructure & DIST & Average distance between crosswalks (m) & 167.223 & 150.976 & 30 & 918 \\  & SLOFE & Longitudinal slope (m) & 0.03 & 0.029 & 0 & 0.154 \\  & LIGHTING & Number of lighting posts more than 7 m & 1.15 & 1.231 & 0 & 4 \\  & & away from the middle of pedestrian crossing & & & & \\  & OBST & Presence of an obstacle on the light pole (Yes & & & \\  & & 1, No = 0) & & & \\  & & Functional Road Classification & & & & \\  & C1 & (Collector and Principal Distributor = 0, Local & & & \\  & & Distributed and Local Access = 1) & & & & \\ Road & CZ & (Collector and Local Distributor = 0, & & & \\ infrastructure & LANES TF & Principal Distributor and Local Access = 1) & & & & \\  & LANES TF & Number traffic lanes & 2.8 & 1.381 & 1 & 6 \\  & WIDTH\_W & Carriageway width (m) & 3.399 & 0.422 & 2.775 & 4.9 \\  & DIRECTIONS & Traffic directions (Obs-way = 1, Two-way = 0) & & & \\  & R\_MED & Raised Medians (Yes = 1, No = 0) & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Model dependent and explanatory variables. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Category** & **Variable** & **Description** & **Mean** & **Sid. Dev.** & **Min** & **Max** \\ \hline \multirow{8}{*}{Traffic characteristics} & LuVped (Ped) & Natural logarithm of pedestrian traffic & 6,093 & 0.755 & 4,143 & 7.781 \\  & (Ped) & volume during the peak period (Ped/h). & (57.277) & (423.438) & (62.968) & (2394.620) \\  & & Offset variable & 6,976 & 0.797 & 4.823 & 8.539 \\  & LuVeb (Veb) & Natural logarithm of vehicle traffic volume & (1419.900) & (1080.182) & (124.305) & (5109.930) \\  & LuSpV (SPV) & Natural logarithm of the sum of pedestrian & 7,995 & 0.678 & 5,451 & 8.758 \\  & & and vehicular traffic volume during the peak & (1995.177) & (1249.166) & (232.939) & (6363.904) \\ \cline{1-1}  & & & & & \\ \cline{1-1}  & LuPVQ (PVQ) & Natural logarithm of the product between the pedestrian volume and the squared & 20,045 & 1.993 & 14.337 & 244.253 \\ \cline{1-1}  & & vehicular volume (Ped \(\times\) Veb\({}^{2}\)/h) & (222887144.864) & (5148747229.305) & (1684557.621) & (3412977944.548) \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._The outstanding variables of those groups, in addition to those identified in the literature review, were associated with pedestrian infrastructure. They help to evaluate the impacts of the dimensions recommended for this type of infrastructure and to assess the implementation of policies to support the mobility of pedestrians. Examples of such variables are sidewalk continuity, unobstructed space for pedestrian mobility, and the recommendable distance separating regulated crossings.