The authorities are planning bicycle parking standards but are silent on the quality of paths for sharing ("More bicycle parking to be rolled out at MRT stations"; May 10).

Some countries with shared paths recommend a minimum width of 3m to host moderate bi-directional traffic. This guideline factors in an operating width (OW) of 0.7m each for three users, a shy distance of 0.15m on each side of the path and a buffer zone of 0.3m each between users.

Absolute minimum width is 2m, to allow only single cyclists to pass pedestrians at any one time.

A pedestrian with a small shopping trolley or shopping bags occupies about 0.7m in width, while one using a walking aid may require a broader OW and longer shy distance. Vulnerable pedestrians will likely desire a minimum buffer zone of 0.5m from riders.

For cyclists, the 0.7m OW includes 0.2m of space for zigzagging to maintain balance. Riders of devices with an overall width of 0.7m (including accessories such as panniers) require a greater OW.

Where kerbstones, metal poles supporting covered walkways, hoardings, fences or walls have a common boundary with paths, the Netherlands' Crow Design Manual for Bicycle Traffic 2006 stipulates a shy distance of up to 0.625m.

Many of our paths are around 1.5m wide and become unfit and unsafe for sharing, based on the above considerations. Infrastructure that meets safety standards is crucial to facilitating safe usage and ensuring user safety.

Education and enforcement cannot overcome a facility's lack of safety features. There is a high risk of riders side-swiping pedestrians on unfit paths. Side-swipes can result in falls that may turn into life-changing events.

On unfit paths, responsible riders may experience compliance fatigue if they have to move often at walking pace to safely overtake pedestrians.

Riders of devices without selection for speeds below 15kmh may find it tiresome to brake and restart frequently.

Enforcement officers may have to grapple with forgoing a pursuit, as speeding after an anonymous errant rider intent on evading a summons endangers other users.

Pedestrians on quiet, narrow paths and bus commuters alighting at deserted bus-stop shelters without a bypass face high risks of encountering speeding riders.

Could the authorities articulate their enforcement strategy for these areas?

Safety standards for path sharing should also cover defects-free path surfaces, smooth transverse joints, wheel-friendly utility covers, sight distance unobstructed by vegetation, hoardings or other obstacles, headroom space and other aspects.

Tan Lay Hoon (Ms)