# Estimating Destination of Bus Trips Considering Trip Type Characteristics
## 4 Methodology  
### Definition of Trip Type  
This study defines a trip as the time of boarding a bus to the time of alighting the bus. Furthermore, we check whether the alighting stop information is missing for individual trips, and regarding trips with missing alighting tag information, we classify the trip type (continuous travel, non-continuous recurrent travel, non-continuous non-recurrent travel, route pattern) in terms of the trip continuity and recurrence, based on the identifiable information of other trips of the pertinent card ID. For this, it is presumed that a similar card ID is maintained for the entire time range of the utilized data. Subway trips were excluded from the estimation as passengers are required to tag their transportation cards at the alighting stations, resulting in an alighting tag ratio close to 100%. To determine the trip type, we built the basic DB utilizing the boarding and alighting information in the sequential order of time for all trips on the pertinent day, and the first trip on the next day for each ID. Regarding the first trip on the next day, the data were constructed for estimation in the event that the passenger did not tag the card when alighting the bus on the pertinent day. For continuous travel, trip-chain-based alighting stop estimation methodology is applied, based on the assumption that the passenger boards a bus around the position where the \(i\) route, \(j\)-th alighting stop information is missing. In other words, a trip must occur on the same day or the next day after the alighting tag information is missing, and an estimation-target route must pass through the boarding stop of the next trip within the allowed walking distance. If all these conditions are met, the trip is considered to have occurred continuously and is classified as a \"continuous travel\"; otherwise, it is classified as a \"non-continuous travel.\"  
The concepts of continuous travel and transfer are different. A trip is defined as continuous travel if a passenger utilized two bus routes by transferring once in the middle, while traveling from the origin to the destination. Furthermore, if the passenger travels \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Region**} & **Total Number** & \
\begin{tabular}{c} **Number of** \\ **of Data** \\ \end{tabular} &
\begin{tabular}{c} **Ratio of** \\ **Alighting** \\ **Non-Tag Data** \\ \end{tabular} \\ \hline Seoul & 136,502,534 & 3,933,416 & 2.90\% \\ \hline Busan & 37,366,459 & 21,420,213 & 57.30\% \\ \hline Incheon & 25,191,574 & 780,977 & 3.10\% \\ \hline Gwangju & 8,365,264 & 5,823,725 & 69.60\% \\ \hline Daejeon & 10,800,434 & 1,691,237 & 15.70\% \\ \hline Ulsan & 6,753,704 & 4,767,535 & 70.60\% \\ \hline Sejong & 1,590,931 & 154,489 & 9.70\% \\ \hline Gyeonggi-do & 124,531,413 & 1,588,267 & 1.30\% \\ \hline Gangwon-do & 3,247,020 & 2,058,875 & 63.40\% \\ \hline Chungcheongbuk-do & 4,317,692 & 2,478,044 & 57.40\% \\ \hline Chungcheongnam-do & 4,695,978 & 1,658,766 & 35.30\% \\ \hline Jeollabuk-do & 4,700,207 & 3,455,147 & 73.50\% \\ \hline Jeollanam-do & 3,916,794 & 2,863,507 & 73.10\% \\ \hline Gyeongsangbuk-do & 4,823,337 & 3,902,572 & 80.90\% \\ \hline Gyeongsangnam-do & 13,049,527 & 9,990,513 & 76.60\% \\ \hline Jeju & 4,248,946 & 1,434,272 & 33.80\% \\ \hline total & 394,101,814 & 68,001,555 & 17.25\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Result of analysis on the status of alighting non-tag by city and province based on traffic card data (April 2020). from A to B without transferring, then starts the next trip at B or in the vicinity (within the allowed walking distance) on the same day or the next day, the trip is also defined as continuous travel. Regarding non-continuous travel, because the alighting stop is estimated by searching the past travel history and finding a trip that is determined to have the similarity temporally and spatially to the trip with missing alighting tag, it is selected by utilizing the card ID's past travel history DB.