## 2 Materials and Methods
### Data for Analysis  
The accidents that occurred in Erzurum province were recorded with all the details by Erzurum Metropolitan Municipality. In the study, a total of 1437 accident statistics occurring in winter months in recent years were analyzed. These accident data were obtained from the Erzurum Police Department, Erzurum Metropolitan Municipality and the Turkish Statistical Institute. Since there is a lot of detail on traffic accidents in the data, it was processed and filtered so that only winter conditions and surface conditions were considered. Accidents in winter months can cause the road surface to be icy, snowy and wet, depending on the weather conditions. Therefore, the road surface conditions were classified based on these three conditions. On the other hand, according to the highway geometric standards applied in Turkey, the maximum longitudinal slope in flat or rough cities is between 4% and 6%. For this reason, roads with a longitudinal slope of less than 4% are defined as low-slope roads in the classification of urban road slopes. Roads with slopes between 4% and 6% are expressed as medium-slope roads, and roads with slopes greater than 6% are expressed as high-slope roads. In this case, three classes were created for road surface and slope.  
In Table 1 below, only 15 of the accidents that occurred in the study area during the winter months are shown as examples. For all accidents, the coordinates where the accident occurred, the surface and slope condition of the road at the accident point, and the severity levels of the accident are included in these data.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Number**} & \multicolumn{2}{c}{**Coordinates**} & \multicolumn{2}{c}{**Road**} \\  & **X** & **Y** & **Surface** & **Slope** \\ \hline
1 & 41.28184 & 39.92788 & snowy & moderate \\
2 & 41.26639 & 39.90199 & snowy & high \\
3 & 41.27372 & 39.93020 & icy & low \\
4 & 41.26568 & 39.90548 & icy & moderate \\
5 & 41.26771 & 39.90836 & snowy & moderate \\
6 & 41.24193 & 39.81276 & wet & high \\
7 & 41.28314 & 39.98947 & snowy & low \\
8 & 41.25581 & 39.90624 & icy & high \\
9 & 41.28688 & 39.94039 & snowy & moderate \\
10 & 41.26750 & 39.90951 & icy & moderate \\
11 & 41.22693 & 39.90209 & snowy & high \\ \hline \hline \end{tabular}
\end{table}
Table 1: A sample is taken from data including traffic accidents in the study area.  
Figure 1: Accident points in city center during winter months.  
In order to evaluate road surface conditions and slope factors, which are among the most significant factors in traffic accidents in winter months, a structure called road conditions was created. Three different road surface conditions and three different road slope classes were evaluated together, resulting in 9 different conditions. All the conditions that can occur are shown in Figure 2 below.  
Winter Accident Prevention Based on Road Surface and Slope Conditions  
To significantly reduce the number of accidents in winter months, measures should be tailored to the specific road conditions identified in the image, focusing on both surface and slope characteristics. For icy surfaces (A), it is essential to use de-icing agents and provide clear signage to warn drivers. Additionally, installing reflective road markings can improve visibility in snowy conditions (B) and wet conditions (C), thus helping drivers to maintain better control of their vehicles. On high-slope roads (D), the installation of speed-reducing measures, like rumble strips, and increasing the frequency of road maintenance (e.g., snow clearing and sanding) can prevent accidents caused by loss of control. For moderate slopes (E), a combination of road surface treatments and speed regulation can reduce the risk of skidding or overturning, while on low-slope roads (F), enhanced road drainage systems and better visibility through improved signage can reduce accidents. By addressing these specific risks according to road conditions, it becomes possible to decrease the frequency of accidents in winter months.