## 3 Data Description and Preprocessing
### Data Source
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Variable** & **Category** & **Description** & **Code** & **Frequency** & **Mean** & **Std. Dev** \\ \cline{3-6}
**Category** & **(Binary)** & & AM peak & AM\_Peak & 914 & 0.08 & 0.27 \\ \hline \multirow{8}{*}{Temporal factors} & Time of day & PM peak & PM\_Peak & 1519 & 0.13 & 0.34 \\ \cline{2-6}  & \multirow{2}{*}{Day of week} & Night & Ngt & 3444 & 0.3 & 0.46 \\ \cline{3-6}  & & Monday to Thursday & Mon\_Thu & 6079 & 0.54 & 0.5 \\ \cline{2-6}  & \multirow{2}{*}{Day of week} & Friday to Sunday & Fri\_Sun & 5250 & 0.46 & 0.5 \\ \cline{3-6}  & & Spring (March, April, May) & Spr & 2745 & 0.24 & 0.43 \\ \cline{3-6}  & \multirow{2}{*}{Season} & Summer (June, July, August) & Sum & 3179 & 0.28 & 0.45 \\ \cline{3-6}  & & Fall (September, October, November) & Fall & 2837 & 0.25 & 0.44 \\ \cline{3-6}  & & Winter (December, January, February) & Wnt & 2533 & 0.22 & 0.42 \\ \hline Driver gender & Male & Male & 7412 & 0.65 & 0.48 \\ \hline \multirow{8}{*}{Driver age} & Young age (\(\leq\)25 years) & Y\_AGE & 2516 & 0.22 & 0.42 \\ \cline{2-6}  & Middle age (between 25 and 65 years) & M\_AGE & 7379 & 0.65 & 0.48 \\ \cline{2-6}  & \multirow{2}{*}{Cash severity} & Old age (>65 years) & O\_AGE & 1434 & 0.13 & 0.33 \\ \cline{3-6}  & & Injury crash & Inj & 2638 & 0.23 & 0.42 \\ \cline{2-6}  & \multirow{2}{*}{Cash severity} & Fatality & Fatality & 144 & 0.01 & 0.11 \\ \cline{3-6}  & & Alcohol/drugs & Alc\_Drugs & 105 & 0.01 & 0.1 \\ \cline{3-6}  & \multirow{2}{*}{(binary)} & Alcohol & Alc & 399 & 0.04 & 0.18 \\ \cline{3-6}  & & Drugs & Drugs & 86 & 0.01 & 0.09 \\ \cline{3-6}  & & Residential & Res & 168 & 0.01 & 0.12 \\ \cline{3-6}  & & Business & Business & 339 & 0.03 & 0.17 \\ \cline{2-6}  & \multirow{2}{*}{Cash event} & Road departure & RdwyDprt & 5290 & 0.47 & 0.5 \\ \cline{3-6}  & & Head-on & HeadOn & 64 & 0.01 & 0.07 \\ \cline{3-6}  & \multirow{2}{*}{(categorical)} & Rear-ended & RearEnd & 3591 & 0.32 & 0.47 \\ \cline{3-6}  & & Sideswipe & SdSwp & 2093 & 0.18 & 0.39 \\ \hline \multirow{8}{*}{Roadway condition} & Water on roadway & Rd\_WtRdwy & 329 & 0.03 & 0.17 \\ \cline{3-6}  & & Animal on roadway & Rd\_AnRdwy & 264 & 0.02 & 0.15 \\ \cline{3-6}  & & Object on roadway & Rd\_objRdwy\_Others & 784 & 0.07 & 0.25 \\ \cline{3-6}  & & Cellphone & CellPh & 123 & 0.01 & 0.1 \\ \cline{3-6}  & \multirow{2}{*}{Driver’s distraction} & Inside the vehicle & InVeh & 331 & 0.03 & 0.17 \\ \cline{3-6}  & & Outside the vehicle & OutVeh & 293 & 0.03 & 0.16 \\ \cline{3-6}  & & Car & Car & 4067 & 0.41 & 0.49 \\ \cline{3-6}  & & Large truck & Large\_Truck & 1340 & 0.12 & 0.32 \\ \hline \multirow{8}{*}{Environmental factors} & Lighting & Dark & Dark & 3843 & 0.34 & 0.47 \\ \cline{3-6}  & conditions & Dusk/dawn & Dusk\_Dawn & 347 & 0.03 & 0.17 \\ \cline{1-1} \cline{2-6}  & Weather condition & Rain & Rain & 2578 & 0.23 & 0.42 \\ \cline{1-1} \cline{2-6}  & \multirow{2}{*}{Speed limit factors} & Fog/snow & Fog\_Snow & 164 & 0.01 & 0.12 \\ \cline{1-1} \cline{2-6}  & & Speed limit greater than 60 & PtsSpd\_greaterthan\_60 & 9339 & 0.82 & 0.38 \\ \cline{1-1} \cline{2-6}  & & mph & mph & & & & \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._