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…

There is a freeway on-off ramp on I-5 and South 317th street. There is a round-about then to the east is the on-off ramp which is all 2 person or more HOV (High Occupancy Vehicle) at 47.31779° N, 122.29734° W.

PS: They are building light rail just south of South 317th street which crosses over that street heading north next to I-5 so you need to zoom in to see the road.

The round-about is NOT HOV but everything to the east of it for the on-off ramp is 2 person or more HOV. I don’t know how to do it myself so if someone could do it for me I would really appreciate it. I’m sure it is easy for those that know what to do. If you have any questions just let me know.

HELP! I need help getting this on/off ramp changed to show that this is an HOV (high occupancy vehicle) on/off ramp to/from I-5 freeway in Federal Way, WA. I looked at how to modify this but this is just not a format that I was able to figure out after trying for about an hour.

Help from someone would be MUCH appreciated. Right now this affects anyone that uses this map with for making routes to/from places including Tesla’s FSD (Full Self Driving) software. I’m sorry if you hate Tesla but please, I’m just a person who likes my electric car and would use this update multiple times a week if this was updated. Thank you in advance. :slight_smile:

Hi, this is a very old topic, so that might explain why you didn’t get a prompt answer the first time. Old topics like this are full of information that’s out of date, so often we like to start fresh with a new one. But now that we’re here, let’s see what we can do about the HOV ramps.

This looks like the area you’re experiencing problems with:

As far as I can tell, these ramps are tagged as:

  • motor_vehicle=no, which keeps car routers from using the ramps in general
  • hov=designated`, which overrides that restriction for HOVs only
  • hov:minimum=2, which specifies that only vehicles with two or more people count as HOV (as opposed to some of the higher minimums WSDOT sometimes posts)

These tags should be enough to prevent a routing engine from sending cars down the ramp unless it happens to know the user qualifies as an HOV. For example, using the main OSM website, we can see that Valhalla avoids this ramp by default using the community-developed car profile.

If your Tesla is routing you down the ramp anyways, it probably isn’t respecting the hov=designated tag (which is somewhat less common in the U.S.). Or it might not even be using OSM data for this purpose. Some data consumers only use OSM data for the base map, or only for routing, or only for a subset of the navigation data, such as speed limits or parking aisles. Reportedly, Tesla does use the Valhalla routing engine, but this doesn’t necessarily mean they use the same profile or data.

Unfortunately, it’s hard to know the exact cause of the behavior you’re seeing, since Tesla has been tight-lipped about any use of OSM. But if you know of any other ramps that OSM might have mistagged, at least we can ensure correctness for users of other software or hardware.


Thank you VERY much for your answer.

The issue is that the Tesla mapping software is NOT taking us on the freeway on/off ramp that I described.

You are correct in that it should be updated to be marked as "

  • hov:minimum=2”

Can you help me get it changed so that it is corrected to be as above. Note that there is both “on” and “off” ramps for this. If you have any questions I would be more than happy to help in any way that I can.

Thank you very, very much.

May your journeys on roads always be pleasant ones and may all the roads be marked correctly. Of course things will never be perfect but we can wish for them. Right? And hopefully Tesla will use the data to correct their maps so that our car can route properly which it does not currently do.

Ah, I read your post backwards, thinking you had gotten routed down the ramp incorrectly. In any case, the relevant data has already been tagged with hov:minimum=2 since 2015. Unfortunately, this shows that the software isn’t respecting the proper tags, assuming it’s using OSM data to begin with. I don’t know if there’s anything else we can do in OSM about this. Maybe you could try Tesla’s support channels? Sorry we can’t be of more help.

Just you letting me know that OSM is correct is help. This way I can go to Tesla and tell them that the OSM map is correct but that they are not importing the data into their mapping software therefore I have to manually drive onto the HOV onramp (saving five minutes or more vs the normal on/off-ramp.

Have a wonderful day!

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Everything is correct except that it should be 2 or more people, not 3 or more.