# Study on the Minimum Operation Width of Human-Powered Bicycles for Safe and Comfortable Cycling
## 2 Literature Review  
The minimum operational width incorporates the physical dimensions of standard bicycles (BW) along with necessary deviations to accommodate wobbling motions, which are critical for maintaining stability and achieving optimal cycling speeds (wd1), as shown in Figure 1. This concept has been articulated in bikeway design manuals across various countries and regions, albeit under different terminologies, as highlighted in Table 1, which presents the terms used. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Country/Region**} & \multirow{2}{*}{**Year**} & \begin{tabular}{c} **Minimum Operation** \\ **Width–One Cyclist** \\ **(m)** \\ \end{tabular}  & \multirow{2}{*}{**Typical Bicycle**} & \multirow{2}{*}{**Remark 2**} \\  & & & & **Width (m)** & \\ \hline \multirow{2}{*}{USA [46]} & \multirow{2}{*}{2012} & \multirow{2}{*}{1.20} & \multirow{2}{*}{0.75} & \multirow{2}{*}{Including natural side-to-side movement that varies with speed, wind, and bicyclist proficiency; 1.5 m for preferred operation width} \\ \cline{1-1} \cline{6-6} \cline{8 It can be seen that not all manuals consider the speed influence. The Chinese mainland standard specifies a lane width of 1 m for design speeds ranging from 10 km/h to 15 km/h. However, it remains unclear whether this width is adequate for exclusive bicycle paths with typical design speeds exceeding 15 km/h. While some international bikeway design manuals, such as those from Australia, the UK, and the Netherlands, address the impact of speed on lane width requirements, these standards cannot be directly applied to China due to differences in road environments, vehicle types, and cyclists' experiences. Moreover, there is a lack of field experiments to empirically validate the lane width values specified in design manuals fulfilling different speeds [44; 54]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Country/Region**} & \multirow{2}{*}{**Year**} & \multicolumn{2}{c}{**Minimum Operation**} & \multirow{2}{*}{**Typical Bicycle**} & \multirow{2}{*}{**Remark 2**} \\  & & **Width—One Cyclist** & & & \\  & & **(m)** & & & \\ \hline \multirow{4}{*}{Australia [47]} & \multirow{2}{*}{2017} & \multirow{2}{*}{1.00} & \multirow{2}{*}{0.80} & \multicolumn{2}{c}{“Cyclist design envelope” or} \\  
Some studies indicated that some of the specified operation widths in these manuals may be insufficient to accommodate all conditions at different speeds. For instance, a 1998 study [55] revealed that researchers from the US, Norway, Sweden, Germany, and the Netherlands generally advocate for a lane width exceeding 1.2 m to accommodate bicycles' operational requirements. Similarly, the Japanese road design manual [56] suggested that a 1 m cycle lane width is suitable only for cycling speeds below 15 km/h, and wider lanes should be provided for higher speeds. Several observational studies have focused on operation width under different conditions. [PERSON] and [PERSON] [57] investigated the influence of cycle lane width on cyclist behavior, traffic flow, and lane capacity, recommending a minimum width of 2.25 m for a one-way two-lane cycle track, equating to 1.13 m per lane. [PERSON] et al. [21] conducted a cyclist behavior observation experiment in Xi'an, China, comparing cycling speeds and vehicle gaps on four types of non-motorized lanes. They recommended a width of 3 m for non-motorized lanes, with a minimum of 2.6 m (considering E-bike speed limits), corresponding to 1.5 m (1.3 m) per lane. [PERSON] et al. [58] conducted a comprehensive video survey of eight physically isolated non-motorized lanes in Nanjing, China, to classify various types of abreast cycling and overtaking behaviors. Based on their observations, they proposed a minimum width of 2.5 m for separated bicycle lanes, equating to 1.25 m per lane width. A more extensive study on bike lane width determination [59] suggested different lane and buffer widths based on observations of bicycle, parked vehicle, and moving vehicle lateral positions.