[Tagging] Clarification unclassified vs residential

Fernando Trebien fernando.trebien at gmail.com
Sat Mar 2 13:24:20 UTC 2019

On Fri, Mar 1, 2019 at 9:22 PM Sergio Manzi <smz at smz.it> wrote:
> On 2019-03-02 00:59, Graeme Fitzpatrick wrote:
> Being picky, but (at least out here) they're not exempt, they're just allowed to break them :-) eg in an emergency, an ambulance can go through a red light, but if they cause an accident by doing so, the driver will be charged (& they have been)
> Sorry, but I'm inclined to categorize the above as BS, or "fake news", if you prefer, until you provide evidence (in which case I'll apologize and eat my words).
> In every street code I know of, emergency and law enforcement vehicles with alarm and light turned on HAVE PRECEDENCE on the traffic, regardless the status of traffic lights, with all the legal implications that derive from that.

But that's not what emergency=yes means. What that tag means is that
emergency vehicles are legally allowed to travel into/through a
particular way when handling an emergency (rescuing a patient, putting
down a fire, chasing a criminal, etc.). The precedence/priority a
vehicle gets on traffic is currently not represented by any tag in

For example, say that a police car is parked next to the Pantheon in
Rome, and the officers are informed that a criminal needs to be chased
and is currently next to Santa Maria della Concezione. Is the police
car legally allowed to shortcut through the pedestrian via della
Maddalena without having to ask permission? Or is it legally required
to go around like other civilian vehicles [1]?

I know that so far the discussion has centered on two values,
emergency=yes/no. But there may be other possibilities, such as
emergency=destination/discouraged. For instance, emergency=discouraged
is the legal situation in Brazil on ways that are not allowed for
civilian motor vehicles. Other countries may have by default
emergency=destination (only access is allowed, shortcutting from one
end to the other is not) or emergency=yes (shortcutting is ok). I
think emergency=no is really unlikely.

emergency=discouraged would allow data consumers (routing apps) to
apply some sort of penalty, whereas emergency=destination would forbid
passage through ways from one end to the other. In this example [1],
the router might choose to go through the (troublesome) pedestrian
ways because the route is much shorter, but in other cases (example:
[2]) the shortcut wouldn't make so much sense. If
emergency=destination is used, then the emergency vehicles would be
prohibited from using the pedestrian ways in both cases, unless the
emergency target/destination was within the mesh of pedestrian ways.

[1] https://www.openstreetmap.org/directions?engine=graphhopper_car&route=41.89868%2C12.47640%3B41.90122%2C12.47645
[2] https://www.openstreetmap.org/directions?engine=graphhopper_car&route=41.90256%2C12.48817%3B41.89842%2C12.47573

Fernando Trebien

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