I have a question. I want to add the tag hov=yes for express lanes in California. What is the best way to go about it? In some places, express lanes are separated by plastic bollards, and we have separate lanes for them in OSM (Example SR 91 Express Lanes Way: 91 Express Lanes (482532984) | OpenStreetMap). However, in other places, where the lanes are only separated by double white lines, we also have separate lanes in OSM for express lanes (I-70 Express Lane Colorado Way: I-70 Express Lane West (1074328791) | OpenStreetMap). For I-580 express lanes in California, we do not have a separate lane in OSM. How should I go about adding the hov tag there? Is it correct to add the tag to the freeway, or does a separate lane need to be drawn first?
Additionally, please suggest what other tags could be used to tag express lanes.
In general, we create a separate highway=* way, forming a dual carriageway, any time there’s a physical separation or barrier between the lanes. Closely spaced bollards on freeways count as physical separation because most vehicles wouldn’t reasonably cross the bollard strip. On the other hand, if it’s just a double white line, use change:lanes=* to indicate the lane change restriction along the main highway.
Chances are that any HOV lane you encounter here is already correctly drawn, since California’s major cities have already had a lot of attention from individual mappers and mapping teams focused on navigation. HOV-related tags may be in slightly worse shape.
Use the hov=* key when the entire roadway represented by the highway=* way is reserved for HOVs, and hov:lanes=* when different lanes have different rules about HOVs. As you can see from that page, some other tags like hov:minimum=* are also commonly used in these situations.
Note that hov=* alone is for any carpool lane, not necessarily an express lane. Many of the express lanes in the Bay Area are HOT lanes, in which HOVs must still pay a discounted toll. Use the toll=* and toll:hov=* keys too.
If you’re mapping based on street-level imagery, you can find more relevant tags by searching our California MUTCD pages for “carpool” or “HOV”. Unfortunately we haven’t uploaded sign diagrams for each relevant sign, but hopefully you’ll be able to follow the tagging suggestions based on the sign descriptions:
Not sure how much bitrot has effected things over time, but about 5 years ago I went over I 405 in metro Los Angeles inch by inch to tag all the lanes including the HOV lanes. Might be a good example starting place.