Quebec: How to distinguish autoroutes from other highways?

The legislation in Quebec defines default speed limits (=when no sign overrides this) of 100 km/h for autoroutes and 90 km/h on other paved highways:

(source)

Thus, there is a necessity to be able to distinguish roads designated as autoroutes from other national highways. Whether a highway is an autoroute or not, cannot be linked to physical properties of the road (e.g. dual carriageway / all roads tagged as highway=motorway), at least not by law, because

(source)

In other words, the law does not dictate any hard requirements for a highway to be designated as an autoroute. How it looks in the reality I do not know, but not sure if it is relevant unless the situation is absolutely unambiguous.

I also noticed that unlike how autoroutes are referred to in the wikipedia, autoroutes in OSM are not tagged like ref=A-20 etc. but simply ref=20.

So, my question: Is it possible to determine whether a highway is an autoroute based on the tags of that highway? Are all autoroutes consistently tagged in a way so that they can be clearly distinguished from other highway?
And, well, if not, what’s your suggestion for a tag that denotes this?

Hello!

This link will help you clarify. It comes straight from the Government’s geographical data, including those from the Ministry of Transportation:

https://geoegl.msp.gouv.qc.ca/igo2/apercu-qc/?context=mtq&visiblelayers=bgr_v_sous_route_res_sup_act

In the Montreal area, almost all motorways have been tagged correctly, realigned, the number of lanes have been validated and added, and the transitions are there too. Speed limits are verified too.

2 Likes

This might be influenced by the broader Canadian practice of simply referring to highways by number alone (e.g., “Highway 401”). I’m unsure if there’s a strong reason for QuĂ©bec routes to follow that convention, since there is a consistent alphanumeric abbreviation scheme. Regardless, you can unambiguously identify a motorway as carrying a QuĂ©bec autoroute by its membership in a route relation tagged network=CA:QC:A.

1 Like

There’s a very simple reason that the ref tagging on Quebec highways doesn’t use “A-__” prefixes: by definition all provincial highways numbered 1-99 and 400-999 are autoroutes. The numbering doesn’t overlap with other classifications of provincial highways, so you don’t need to disambiguate any further. It’s not like in the US where you might have “Interstate ##”, “US Route ##” and “State Route ##” all in the same state, or “Autobahn ##” and “Bundestraße ##” in Germany. (Keep in mind there is no overarching federal highway system or standard in Canada.) A Quebec highway with ref=20 for example is, by definition, an autoroute; a Quebec highway ref=234 is by definition a lower-tiered ‘route’.

The tagging of autoroutes is well-defined at FR:Québec/Réseau routier - OpenStreetMap Wiki (FR) / Québec - OpenStreetMap Wiki (EN)

Yes, since @westnordost’s default speed limits parser necessarily varies rules by jurisdiction, this heuristic should be workable. For completeness, note that the forest routes are being tagged with alphanumeric way refs to avoid conflicting with the autoroute numbering scheme, for example ref=R0404, corresponding to what’s signposted as “R 404” on a blue shield. (There are also route relations tagged with network=CA:QC:R, but not as comprehensively as for autoroutes.)

1 Like

Yes, the forestry roads are tagged ref=R####, as the respective blue shield signs do read “R ####”. (Whereas the routes and autoroutes just have a numbered shield with no ‘A’ or ‘R’.) Note also that the forestry roads are now four digits, which may or may not be reflected in posted signage, but there is a method to the madness in that the first two digits in the four-digit code correspond with the administrative region the road is located in. E.g. all forestry roads that begin with ‘04’ are in Mauricie.

1 Like

So, are all autoroutes in Quebec tagged as highway=motorway?

Or highway=trunk.

And are all highway=trunk and highway=motorway in Quebec autoroutes?

Probably
? :man_shrugging:

I think you’re getting to a point where your questions are probably best and most easily answered by just looking yourself.

EDIT: I don’t mean to be rude, but I did link the tagging guidelines earlier


Looking where? Is something to that effect documented in the wiki?

Oh well, nevermind. It is, and you also provided a link earlier:

  • Motorway: autoroutes, including the two-lane ways where you can drive 100, and spur roads with 4xx, 5xx, 6xx or 9xx designations;
  • Trunk: autoroute part of National Highway Service (federal) (NHS) that is not dual carriageway (ie: double central yellow line and not separated by grass). Good example is the autoroute 50 between Lachute and Gatineau as well as the 117 up to Ontario border.

https://wiki.openstreetmap.org/wiki/Québec#Roads

I changed the default speed limits page accordingly:

https://wiki.openstreetmap.org/w/index.php?title=Default_speed_limits&type=revision&diff=2589542&oldid=2581496

1 Like

No, most trunk roads are not autoroutes. For example:

Some trunk roads are on autoroutes, such as the Route de la Bravoure. My impression is that QuĂ©bec is more or less using a mix of connectivity- and designation-based definitions of highway=trunk. The definition posted above incorporates the National Highway Service System. This is often tagged with NHS, but I don’t know if it’s consistent enough to use in your software.

1 Like

Okay, I corrected the fitler accordingly. The filter is now ref~[4-9][0-9][0-9] or {motorway}

https://wiki.openstreetmap.org/w/index.php?title=Default_speed_limits&type=revision&diff=2591843&oldid=2591832

Correct me if I’m wrong, but I was under the impression that autoroutes also go from 1 to 99 (the “main” class, as opposed to the three-digit “spur” class).

I know you aren’t very interested in edge cases, but there are regional routes tagged as highway=motorway, such as Way: â€ȘRoute 138‬ (â€Ș104836585‬) | OpenStreetMap and Way: â€ȘAutoroute RenĂ©-Levesque‬ (â€Ș48776667‬) | OpenStreetMap.

In fact, the word autoroute can appear in the name of a road that isn’t designated as an autoroute, as the French translation of the English word “expressway”, for example in Route 136 (Autoroute Ville-Marie). This leads me to wonder if the law you cited applies to anything that is built as an freeway/expressway or anything that is designated as an autoroute.

You are right, I misread @hoserab earlier comment.

The latter is a very, very, very specific edge case, in that Autoroute René-Levesque is co-signed as Autoroute 20 north of the Champlain Bridge and Autoroute 15 south of the bridge, but the segment between the on/off-ramps to/from the bridge is technically part of neither autoroute.