# Review on Soft Mobility Infrastructure Design Codes
## 2 Codes for Soft Mobility Infrastructure
### Design Features  
#### 2.3.1 General Layout  
The laws, regulations, and design standards of many countries and regions around the world stipulate the minimal width of bicycle lanes as it plays a vital role in the capacity and safety of SMIs [43]. Most countries and cities (NZ, GR, DK, BJ) have detailed regulations on lane width. A typical cross-section plan of bicycle and pedestrian SMI widely used appears in Figure 2.  
Where, a--Curb or buffer that divides the bicycle and motor vehicles, b--Width of bicycle lane or path, b--Physical width of a bicycle, b1--Lateral clearance for the bicycle lane or path, b2--Spacing for bicycles, hb--Height clearance for bicycles, p--Width of pedestrian passage or path, p0--Physical width of a pedestrian or a wheelchair, p1--Lateral clearance for the pedestrian passage or path with bicycle lane or path (\"street furniture and greening zone\"), p2--Spacing for pedestrians, p3--Lateral clearance for the pedestrian passage or path with buildings (\"frontage\") and hp--Height clearance for pedestrians. The existence and eventual value of an upper limit for SMI lane width is not based on evidence but may be directly decided by relevant authorities. The minimal width value comes from the estimation of the dynamic width of the moving object. Specifically for one-way bicycle lanes, the minimum width requirement varies from 0.75 m (NZ) to 3.5 m (GR), with the most common value (the dominant value that appears in more than half of the analyzed codes) being 2.0 m. For two-way bicycle lanes, the minimum width requirement varies from 2.0 m (DK) to 4.7 m (NZ), with the most common value being 3.0 m. As for pedestrian paths, the minimum width requirement varies from 0.9 m (AT) to 4.5 m (HK), with the most common value being 3.0 m.  
Figure 2: Typical cross-section plan for SMI. Meanwhile, there are also recommended width given in the codes. For one-way bicycle lanes, this width varies from 1.5 m (JP) to 4.5 m (BJ), with the most common value being 2.5 m. For two-way bicycle lanes, it varies from 2.5 m (AD) to 4.8 m (NZ), with the most common value being 3.5 m. As for pedestrian paths, it varies from 1.5 m (TZ) to 5.0 m (BJ) with the most common value being 3.5 m.  
However, some countries and regions do have specific formulas to determine lane width, such as the CN formulas shown as Formulas (1) and (2) [26]. For pedestrian:  
\[W_{p}=\frac{N_{p}}{N_{w1}}\times W_{1} \tag{1}\]  
For non-motor vehicles:  
\[W_{b}=\frac{N_{b}}{N_{b1}}\times W_{2}+0.25\times 2 \tag{2}\]  
where  
\(W_{p}\)--Width of the pedestrian lane (m);  
\(N_{w}\)--Peak-hour pedestrian flow on the pedestrian lane (ped/h);  
\(N_{w1}\)--Design capacity of a single pedestrian lane (ped/h);  
\(W_{1}\)--The width of a single pedestrian lane (m) which refers to the b\({}_{0}\) in Figure 2;  
\(W_{b}\)--Width of the non-motor vehicle (m);  
\(N_{b}\)--Peak-hour non-motor vehicle flow on non-motor vehicle lane (veh/h);  
\(N_{b1}\)--Design capacity of a single bicycle lane (veh/h);  
\(W_{2}\)--The width of a single bicycle lane (m) which refers to the p0 in Figure 2;  
0.25--Lateral clearance of the non-motor vehicle lane (m). Clearance height refers to the minimum vertical space required to ensure the safe passage of pedestrians and bicycles. Unlike motor vehicles, which are calculated by \"fixed height + safety margin\", the height of pedestrians and cyclists has dynamic characteristics, so the determination of this indicator needs to consider both human characteristics and safety needs. Countries generally use empirical numerical methods to set it: first determine the basic parameters based on the standard height of the adult population in the country and then add the dynamic safety margin. The final clearance height value is usually significantly lower than the longitudinal safety space standard for motor vehicles (4.7 m, as shown in Figure S1 in the Supplementary Materials). This differentiated setting logic stems from the essential difference between pedestrians and vehicles in terms of movement trajectory and space occupancy.