# Casualty Analysis of the Drivers in Traffic Accidents in Turkey: A CHAID Decision Tree Model
## 3 Material and Method
### Pre-Processing-1
#### 3.2.3. Combining
\begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**Attributes** & **F** & **\%** & **Attributes** & **F** & **Attributes** & **F** & **\%** \\ \hline _Dependent attribute_ & & & _Independent attributes_ & & & _Independent attributes_ & \\ _Drier severity_ & & & _Road Section_ & & & _Vertical road geometry_ & \\ Injured & 67,478 & 0.63 & Divided & 42,344 & 0.40 & No-slope & 82,166 & 0.77 \\ No injured & 38,762 & 0.36 & Two-way & 14,693 & 0.14 & Sloping & 24,628 & 0.23 \\ Fatal & 554 & 0.01 & One-way & 3354 & 0.03 & _Time-period_ & & \\ _Independent attributes_ & & Four-legs/roundabout & 29,087 & 0.27 & 00:00-06:00 & 15,198 & 0.14 \\ _Manner of accident_ & & & Intersection (Y) & 2205 & 0.02 & 06:00–12:00 & 24,048 & 0.22 \\ Rear-end & 15,226 & 0.14 & Intersection (T) & 9860 & 0.09 & 12:00–18:00 & 36,277 & 0.34 \\ Sc & 36,807 & 0.34 & Interchange & 652 & 0.01 & 18:00–24:00 & 31,271 & 0.29 \\ Sideswipe & 1265 & 0.01 & Other int. & 4599 & 0.04 & _Light cond._ & & \\ Rsr & 30,905 & 0.29 & _Location type_ & & & Daylight & 65,674 & 0.62 \\ Hc & 4863 & 0.05 & Urban & 81,709 & 0.77 & Gsl & 28,927 & 0.27 \\ Bo & 15,606 & 0.15 & Rural & 25,085 & 0.24 & Bsl & 12,193 & 0.11 \\ Bv & 2122 & 0.02 & _Road alignment_ & & & _ Weather_ & \\ _Drier fault_ & & & Straight & 88,945 & 0.83 & Clear & 90,924 & 0.85 \\ Speeding & 54,948 & 0.52 & Curve & 15,359 & 0.14 & Rainy & 11,416 & 0.11 \\ Ftc & 12,050 & 0.11 & Sharp Curve & 2490 & 0.02 & Snowy & 1294 & 0.01 \\ Fty & 18,366 & 0.17 & _Road Type_ & & & Other & 3160 & 0.03 \\ It & 6072 & 0.06 & Streets & 69,177 & 0.65 & _Drier license_ & & \\ Ilc & 15,358 & 0.14 & State highways & 28,750 & 0.27 & Yes & 102,035 & 0.95 \\ _Weekd_ & & & Provincial roads & 1979 & 0.02 & No & 4759 & 0.05 \\ Weekdays & 73,621 & 0.69 & Motorways & 3449 & 0.03 & Unknown & & \\ Weekend & 33,173 & 0.31 & Other roads & 3439 & 0.03 & _Sensor_ & & \\ _Number of vehicles_ & & & _Surface condition_ & & Spring & 24,752 & 0.23 \\ One-vehicle & 44,995 & 0.42 & Dry & 87,190 & 0.82 & Summer & 30,787 & 0.29 \\ Two-vehicles & 53,774 & 0.50 & Wet & 19,604 & 0.18 & Autumn & 27,822 & 0.26 \\ Multi-vehicle & 8025 & 0.08 & _Drier education_ & & Winter & 23,433 & 0.22 \\ _Drier age_ & & & Primary School & 18,633 & 0.17 & _Year_ & & \\ Young (18–25) & 25,828 & 0.24 & Middle School & 5591 & 0.05 & 2015 & 20,634 & 0.19 \\ Ma 1 (26–40) & 46,253 & 0.43 & High School & 53,761 & 0.50 & 2016 & 16,117 & 0.15 \\ Ma 2 (41–64) & 29,834 & 0.28 & Higher Edu. & 28,809 & 0.27 & 2017 & 15,779 & 0.15 \\ Elderly (65+) & 4878 & 0.05 & _Alcohol usage_ & & 2018 & 15,769 & 0.15 \\ _Drier gender_ & & & Normal & 95,077 & 0.89 & 2019 & 14,420 & 0.14 \\ Male & 92,271 & 0.86 & Drunk driving & 11,717 & 0.11 & 2020 & 11,688 & 0.11 \\ Female & 14,523 & 0.14 & _Traffic signal_ & & 2021 & 12,387 & 0.12 \\ _Vehicle usage_ & & & Yes & 12,539 & 0.12 & & \\ Private & 102,859 & 0.96 & No & 94,255 & 0.88 & & \\ Commercial & 2855 & 0.03 & & & & & \\ Others & 1080 & 0.01 & & & & & \\ \hline \hline \end{tabular}  
* F: Frequency, Sc: side collision, Rsr: rollover/skidding/run off road, Hc: head on collision, Bo: bumping into fixed objects and others, Bv: bumping stopped vehicle, Ftc: following too close, Fty: failure to yield, It: improper turn, Ilc: improper lane changing, Ma 1: middle-aged1, Ma 2: middle-aged2, Gsl: good street lighting, Bsl: bad street lighting, Weather cond—other: foggy, stormy.  
\end{table} 
Table 2: Descriptive statistics of analysed dataset.