Which of the following is not a primary factor for bicyclist level of stress?

The reason "Rate of parking turnover" is not considered a primary factor for a bicyclist's level of stress is that it does not directly influence the immediate cycling environment. Bicyclist stress primarily arises from conditions they face while riding, such as the volume of traffic in adjacent lanes, the speed at which that traffic is traveling, and the physical dimensions of the bike lane, including its width.

Curb lane traffic volume affects the perception of safety and comfort for cyclists—higher volumes can lead to increased danger and stress. Traffic speed is similarly significant, as faster-moving vehicles can create hazardous conditions for cyclists, who may feel more at risk in a high-speed environment. Lane width is crucial because insufficient space can lead to conflicts between cyclists and motor vehicles, resulting in heightened anxiety for cyclists.

In contrast, while parking turnover can impact overall traffic flow and availability of spaces, it does not have the same immediate impact on a bicyclist’s experience while riding. Thus, it isn't classified as a primary factor influencing their stress levels on the road.