Sheffield School of Architecture, University of Sheffield, Sheffield, United Kingdom.
PLoS One. 2024 Oct 11;19(10):e0311964. doi: 10.1371/journal.pone.0311964. eCollection 2024.
Comparing the counts of cyclists travelling at specific times of day is one approach to measuring the impact of ambient light level. Here we investigate one source of variance in the magnitude of change seen in previous research-the choice of case and control hour. This was done through an analysis of cyclist flows using data from multiple automated cyclist counters in five cities (Arlington, Bergen, Berlin, Birmingham and Leeds) to determine the odds ratios (OR) for each combination of case and control hour. The results tend to reveal odds ratios above 1.0 indicating that cycling can be deterred by darkness. The odds ratios varied with the choice of case and control hour. For two cities (Birmingham and Leeds), the impact was small, with little difference in ORs between any case and control hour combination. For three cities the variance in ORs was larger. To represent the impact of darkness on cycling flows across the range of case and control hours we suggest the Mantel-Haenszel pooled odds ratio is used, in which the odds ratio for each combination of case and control hour is weighted by the total number of cyclists in that combination. This suggested a statistically significant (p<0.001) deterrent effect of darkness in all five cities.
比较特定时间段内的自行车骑行者数量是衡量环境光照水平影响的一种方法。在这里，我们研究了先前研究中观察到的变化幅度的一个方差来源——病例和对照小时的选择。这是通过对来自五个城市（阿灵顿、卑尔根、柏林、伯明翰和利兹）的多个自动自行车计数器的数据进行自行车流量分析来完成的，以确定每个病例和对照小时组合的比值比（OR）。结果往往表明比值比大于 1.0，表明黑暗会阻碍自行车骑行。比值比随病例和对照小时的选择而变化。对于两个城市（伯明翰和利兹），影响较小，任何病例和对照小时组合之间的 OR 差异不大。对于三个城市，OR 的方差较大。为了代表黑暗对整个病例和对照小时范围内自行车流量的影响，我们建议使用曼特尔-哈塞尔 pooled odds ratio，其中每个病例和对照小时组合的比值比都由该组合中自行车骑行者的总数加权。这表明在所有五个城市中，黑暗都有统计学意义上的（p<0.001）阻碍作用。
