I personally delved deeper into the OSM usage of service=alley in Northern Thailand, and I couldn’t formulate a concrete proposal.
- If we consider roads where bi-directional traffic is possible only at certain spots (width less than 4 meters), this rule would apply to literally millions of roads.
- Conversely, if we consider roads where bi-directional traffic is strictly impossible (no gaps or presence of walls/fence/buildings/sidewalk), we could find a much lower number.
However, there is no standard road width in Thailand; it can have any measurements. This is open to interpretation, and examining usage samples below reveals that service=alley has been applied indiscriminately for various widths (some are 4/5 meters wide) or even for different uses (private driveways).
I routinely modify motorcycle paths (narrower than 2 meters), and distinguishing them is challenging, especially without a visible car parked in the driveway.
Apart from the reasons mentioned earlier, I personally believe that introducing another highway tag based solely on road width not only complicates matters but also increases the likelihood of further editing conflicts.
