How to indicate carpool lanes/ramps on freeways.

This concerns tags and rendering.

Some freeway entrance ramps, (motorway_links), are restricted: only busses, carpools, and sometimes motorcycles are allowed. (These are generally adjacent to ramps which are unrestricted but metered — controlled by a traffic signal during rush hour). There are also carpool lanes, particularly along I-394, (west from Minneapolis). The “carpool” restriction occurs often enough in the Twin Cities, (Minnesota, USA), that I wondered whether a particular tag should be used.

I have started to indicate metered ramps using highway=traffic_signal at the appropriate point. I also use access=permissive for the carpool lane. Mapnik appears indifferent to such distinctions. Osmarender shows the traffic signal and some cross-hatching, respectively, (although the nature of the access restriction is only specified under description, hence not accessible from the rendering). On the street, the carpool ramps/lanes are marked with a diamond symbol, and I wondered whether this symbol was common enough that it should be rendered.

Interestig problem, could you show us some example tagging, links to areas that use it, and some wiki pages? Your problem is very specific and you will need to get in touch with people that are not yet aware of this, so make it easy for them when they find this message… :slight_smile:

I guess carpool lanes are officially known as HOV lanes, (“high-occupancy vehicle” lanes), as described here: . Note related article on I-394: .

I wonder if access=HOV might be the best way to tag this? (access=permissive isn’t really correct, I think).

My examples could still use a bit of work; but how would I provide links to such map areas?

Just link to the slippy map area by påressing “permalink” and getting a link like this:

Perhaps access=carpool might be more descriptive to the general user.

Way #29502024 (oneway eastbound from NE 30th St intersection to I-405 westbound) is restricted to motorcycles and 3-person carpools.* Note that there are two on-ramps, the one heading from northbound is open to all vehicles.

Interestingly, there’s a lane restriction leading up to it: only the right lane can be used for using the northbound on-ramp, starting from NE 24th St. I’ve gotten stuck a couple of times when the right lane was crowded and I didn’t merge in time, I had to loop around.

*SR-520 is, I think, the only highway in Washington state with 3-person restrictions, the other High Occupancy Vehicle lanes have 2-person restrictions, although the High Occupancy Toll lanes on SR-167 add another wrinkle.

I think you have everything you need to tag it and get the data there. (I can’t check if it’s tagged already since the server seems to be down)

Just this statement is abit bothersome, you will need to calssify what you mean by carpool:

  1. three or more people riding in a car
  2. a car pool with two cars used by six persons
  3. a car registered as used by three people, but today only two are using it
  4. a car used by three people.

Number 2. is what I call a carpool.

Ah. The restrictions for that bit of road permit access to:
[]1. three or more people riding in a car or recreational vehicle
]1. three or more people riding in a truck that weighs less than 10k lbs GVW (gross vehicle weight)
]buses (er, PSV)
[*]emergency vehicles

and deny access to:
[]two or more people in a car or recreational vehicle
]trucks that weigh more than 10k lbs GVW
[*]bicycles, pedestrians, horses

More details at

So, given perhaps:

Does that seem right? I’m thinking that highway=motorway_link (and highway=motorway) might imply horse=no and foot=no (and perhaps even bicycle=no) but I’m not sure. Also access=designated might not be right.

meh! have to go now I’ll be back. But to me PSV/HOV seems like very bad tags since it’s almost impossible for me to know what they mean. Bah! unsure about this with acronyms…