# Forecasting the Number of Road Accidents in Polish Provinces Using Trend Models
## 3 Materials and Methods  
More than 38 million people live in Poland (Figure 1). It occupies an area of 312,705 km\({}^{2}\) and is divided into 16 provinces (Table 1, Figure 2). In the states studied, the average reduction in traffic accidents between 2001 and 2021 was more than 56%. Strongest in Kuyavsko-Pomorskie (70%) and Podraskiye (69%), lowest in Rubskiye (32%). The number of automobile accidents depends on the number of residents living in a particular state [59; 60]. The number of accidents in Poland is still very high compared to the rest of the European Union [61]. Therefore, every effort should be made to reduce this value and identify the states with the most traffic accidents (Figures 3-5). Based on Figures 1 and 3, it can be concluded that the highest number of traffic accidents is in the Mazowieckie Province and the highest number of accidents per 10,000 inhabitants is in the Lodz Province. In addition, since this study only used historical data on the number of traffic accidents and did not consider other factors, there is a relationship between the data used, and for this reason the method discussed can be used. Figure 1: Population of Poland from 2001 to 2020 (thousand people) [62]. Considering Figures 3 and 4, it can be seen that the number of accidents is decreasing, and accidents are seasonal. The highest number of accidents occurs in the summer months and the lowest in the winter months. In addition, we can see that the beginning of the COVID-19 pandemic, 2020, disrupted the number of traffic accidents, when there was a huge decrease. Between 2001 and 2021, the largest decrease in the number of traffic accidents, more than 300%, is seen in the following provinces: kujawsko-pomorskie, lubelskie, podlaskie. On the other hand, the smallest decrease, during the analyzed period, was seen in Lubuskie province and amounted to less than 50%. \begin{table}
\begin{tabular}{l r r r} \hline \hline \multirow{2}{*}{**Province**} & \multicolumn{2}{c}{**Area**} & \multicolumn{2}{c}{**Population**} \\ \cline{2-4}  & **in km\({}^{2}\)** & **Total** & **Persons/km\({}^{2}\)** \\ \hline POLAND & 312,705 & 38,265,013 & 122 \\ Lower Silesia & 19,947 & 2,891,321 & 145 \\ Kuyavia–Pomerania & 17,971 & 2,061,942 & 115 \\ Lublin Province & 25,123 & 2,095,258 & 83 \\ Lubusz Province & 13,988 & 1,007,145 & 72 \\ Lodz Province & 18,219 & 2,437,970 & 134 \\ Lesser Poland & 15,183 & 3,410,441 & 225 \\ Masovia & 35,559 & 5,425,028 & 153 \\ Opole Province & 9412 & 976,774 & 104 \\ Subcarpathia & 17,846 & 2,211,229 & 119 \\ Podlaskie Province & 20,187 & 1,173,286 & 58 \\ Pomerania & 18,323 & 2,346,671 & 128 \\ Silesia & 12,333 & 4,492,330 & 364 \\ Holy Cross & 11,710 & 1,224,626 & 105 \\ Warmia–Masuria & 24,173 & 1,416,495 & 59 \\ Greater Poland & 29,826 & 3,496,450 & 117 \\ West Pomerania & 22,905 & 1,688,047 & 74 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Area, population by province in Poland in 2020 [62]. Figure 2: Location of provinces in Poland [62]. Scale: 1:1,000,000. The purpose of this article is to forecast the number of road accidents in Poland in each province. Statistical data of the Police from 2007 to 2021 were used as input data. The following trend models available in Excel software were used to forecast the number of road accidents in each province:  
- Exponential;  
- Linear;  
- Logarithmic;  
- 2 nd degree polynomial;  
- 3 rd degree polynomial;  
- Polynomial of the 4 th degree;  
- Polynomial of the 5 th degree;  
- Polynomial of the 6 th degree;  
- Potentiometric. Figure 4: Number of road accidents in Poland by province from 2001 to 2021 [60]. Figure 3: Accident number per 100,000 population in 2020 [62].