Only according to their PR department. I've never seen any independent report of their actual prevalence in emergency service use.

As others have said, it's proprietary, and I don't want to see a private company becoming a gatekeeper to such an important function. Open standards are available. Google Maps provides Plus Codes, for example, and pretty much all Android users have that without having to install an additional app.

A few months ago I phoned Essex Police (via 999) to report a dangerous obstruction on a major road. Because it was part of the network of roundabouts and slip roads near Stansted Airport, I didn't know the exact name of that road- I could only say that it was the slip-road onto the A120. The 999 operator advised me to use W3W to give the exact location.

Now, this is only one anecdote, and maybe I just happened to get the one operator who had swallowed the what3words PR line- but at least some British emergency services are telling callers to use it.

2nd anecdotal - I've reported several issues such as debris in the carriageway to the South Wales Police via Facebook Messenger.

(Not urgent enough to tie up a 999 operator, and it's faster to pull in somewhere and message, than ring and report via 101.)

They've been happy with location given by w3w.

> They've been happy with location given by w3w.

I'm sure they would be. I'm not doubting that they'll be able to figure it out. Rather, I'm interested to know what they prefer.

Every US public safety agency or SAR group I know of in the US prefers regular latitude and longitude or UTM instead of a commercial apps like that. It's easy enough to get your Lat/Lon or UTM on your phone and you don't even need a special app.

If someone's coordinates don't come through automatically with the 911 call, the dispatcher or person running the search can walk them through finding their location if the person doesn't know how to do it.

W3W is not popular in the US or Canada generally, in large part because it's a proprietary system and so it's not easy to integrate it into the systems that agencies already use for incident management.