# A Path Recommendation Method Considering Individual Driving Preferences
## 2 Factors Influencing Individual Preferences
### Path Properties
#### 2.1.1 Static Properties  
Various static attributes of paths were considered, in order to understand their impact on driver path choice [12; 21; 22]. These static attributes include:  
1. Path length  
This attribute represents the total distance of the roads that a driver travels from origin to destination. Shorter paths are generally preferred by drivers, as they intuitively reflect lower travel costs. The path length \(len_{L}\) is calculated by summing the lengths of road segments:  
\[len_{L}=\sum_{i=1}^{u}len_{l_{i}}, \tag{1}\]  
where \(len_{l_{i}}\) represents the length of the road \(l_{i}\). 2. Number of path lanes  
This attribute reflects the overall number of lanes on a path. It is calculated as the weighted average of the number of lanes on each road segment, considering their respective lengths. Drivers tend to choose paths with more lanes, which are generally indicative of higher road levels or capacities. The number of lanes in the path, \(lanenum_{L}\), is calculated as follows:  
\[lanenum_{L}=\frac{\sum_{i=1}^{u}\bigl{(}lanenum_{l_{i}}\cdot len_{l_{i}} \bigr{)}}{len_{L}}, \tag{2}\]  
where \(lanenum_{l_{i}}\) represents number of lanes in the road \(l_{i}\). 3. Number of path intersections  
This attribute measures the total number of intersections present along a path. It provides an indication of the potential risk of delays during the trip. Drivers generally prefer paths with fewer intersections, as this can minimize their chances of being affected by signal control and experiencing travel-time delays. The number of intersections in a path consists of \(n\) road segments, \(intersection_{L}\), is calculated as:  
\[intersection_{L}=\frac{n-1}{len_{L}}. \tag{3}\]  
4. Path turning index  
This attribute takes into account the number and directions of turns along the path. It reflects the driver's turning actions and measures the ease of driving along the path. Different turning operations require varying levels of attention from drivers, with U-turns typically being the most challenging and straight movements being the easiest. Drivers tend to choose paths with smaller path turning index to complete their trips. The path turning index, \(turn\_index_{L}\), is calculated as:  
\[turn\_index_{L}=\frac{\sum_{i=1}^{u-1}\bigl{(}turn_{i}^{i+1}\bigr{)}}{len_{L}}, \tag{4}\]where \(turn_{i}^{i+1}\) represents the turning value for direction of road \(l_{i}\) towards the next road \(l_{i+1}\), which is calculated as follows:  
\[turn_{i}^{i+1}=\left\{ \begin{array}{l}1,dir_{i}^{i+1}=\text{straight}\\ 2,dir_{i}^{i+1}=\text{right turn}\\ 3,dir_{i}^{i+1}=\text{left turn}\\ 4,dir_{i}^{i+1}=\text{U turn}\end{array} \right.. \tag{5}\]  
In other words, the turning value is assigned as follows: 1 for straight ahead, 2 for a right turn, 3 for a left turn, and 4 for a U-turn. In this paper, the turns were calculated based on the road network information. They were recorded as \(tangle\) and \(tangle\), where \(tangle\) represents the north deviation angle between the direction of traffic and the north direction (clockwise direction is positive) when entering the intersection or exiting the road, while \(tangle\) represents the north deviation angle when entering the road or exiting the intersection. The north deviation angle falls within the value range of \([0^{\circ},360^{\circ})\). The upstream section, denoted by \(tangle_{i}\), represents the direction of travel from \(l_{i}\) into the intersection. On the other hand, \(fangle_{i+1}\) represents the direction of travel from the intersection into the downstream \(l_{i+1}\). The turning angle, denoted as \(angle_{i}^{i+1}\), is calculated as follows:  
\[angle_{i}^{i+1}=\left\{ \begin{array}{l}fangle_{i+1}-tangle_{i}\\ fangle_{i+1}-tangle_{i}+360^{\circ}\end{array} ,fangle_{i+1}\geq tangle_{i}\\,fangle_{i+1}<tangle_{i}\end{array}\right.. \tag{6}\]  
The turning is determined based on the turning angle. An angle of \(0^{\circ}\) corresponds to straight driving, \(90^{\circ}\) to a right turn, \(180^{\circ}\) to a U-turn, and \(270^{\circ}\) to a left turn.