# Study on the Minimum Operation Width of Human-Powered Bicycles for Safe and Comfortable Cycling
## 2 Literature Review
The relevant research findings are summarized in Table 2.  
Observation experiments provide authentic data from the real world by capturing real-time interactions and behaviors in their natural context. However, a significant limitation of this approach is the lack of control over variables, which makes it difficult to establish clear cause-and-effect relationships. As a result, it is challenging to generalize the findings to other conditions, as the lack of experimental control in observational research limits the ability to apply these results to different contexts or environments. In contrast, field experiments offer the advantage of manipulating specific variables while still operating in real-world settings, allowing researchers to draw more definitive conclusions about causal relationships. To date, only three field experiment studies have been conducted to explore the factors impacting minimum operation width determination using lateral position measurements as the primary method of assessment; two in the Netherlands, one in 1980 [50] and another in 2023 [54], and a third in South Korea [44]. [PERSON] and [PERSON] [50] measured lateral deviation during field experiments for the course-holding process, taking into account factors such as speed (fastest, slowest, and leisurely, 16 km/h, 1.3 km/h, and 11 km/h, respectively, as per their test results), surface unevenness, side wind, and riding with one or two hands on the handlebars. Based on a 0.75 m physical contour plus the deviation, their study indicated cyclists and moped riders need a width of 1 m on straight roads, and the lowest speed needs 0.4 m (0.2 m vs. 0.6-0.8 m) more deviation. The other Dutch study chose 1.0 m, 1.5 m, and 2.0 m width scenarios without \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Country/Region** & \
\begin{tabular}{c} **Minimum Lane** \\ **Width (m)** \\ \end{tabular} &
\begin{tabular}{c} **Typical Bicycle** \\ **Width (m)** \\ \end{tabular} & **Remark for Inclusion** & **Research Method** \\ \hline Denmark [57] & 1.13 & - & One-way cycle track & Synchronized video recording \\ China/Xi’an [19] & 1.30–1.50 & 0.60 (bicycle) & Considering mixed & Video recording and lateral \\  & & \& 0.68 (e-bike) & traffic with e-bikes & position measuring \\ China/Nanjing [58] & 1.25 & - & Separated bicycle lane, & A dual-camera recording and \\  & & & with e-bikes & lateral position measuring \\  & & & Adjacent to parking & Camera recording and lateral \\ USA [59] & 1.20–1.50 (4–5 ft) & - & area, not including & position measuring \\  & & & buffer width & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Minimum operation width by observation study in academic research. interaction and 1.5 m and 2.0 m width scenarios with a simulated oncoming cyclist without controlling speed, but the data were screened for speed over 10 km/h. By measuring lateral deviation using LIDAR and GPS, [PERSON] et al. recommended a minimum width of 1.25 m for half of the two-way bicycle tracks' width, based on an experiment considering meeting scenarios [54]. In the third study [44], [PERSON] et al. employed real-time kinematics global positioning system (RTK GPS) technology to precisely track bicycle position and trajectories. Through over 300 tests conducted on 1.1 m, 2 m, and 3 m widths at three preset speeds of 10 km/h, 20 km/h, and 30 km/h, they recommended a desired minimum Essential Maneuvering Space (EMS) of 1.6 m. The findings, conditions, and methods of the relevant research are presented in Table 3.  
In summary, while design manuals specify minimum operational widths for bikeways, they often do not fully account for the influence of cycling speed, and there is a limited amount of empirical research validating these specified widths. Among the empirical studies, most of them rely primarily on observational methods [57; 58; 59; 21], which are inadequate for establishing causal relationships.