singletonpa/bicycle-safety-roundabouts: Initial release of survey data and stated preference analysis

This is an initial release of the "MPC-603 Investigating bicyclist safety perceptions and behaviors at roundabouts" (bicycle-safety-roundabouts) research project. It contains survey data as well as information about the analysis of stated preferences. Future releases will contain information about the analysis of perceived comfort and stated behaviors.本数据集为「MPC-603：环岛骑行者安全认知与行为研究」（bicycle-safety-roundabouts）科研项目的首个公开版本，包含调查问卷数据以及陈述性偏好分析相关资料。后续发布版本将补充感知舒适度与陈述性行为分析的相关内容。