Okay, my name is Monica Brandeis. Good afternoon, everyone. Criterion OSM team developed the map quality measurement process to actually find map errors using AliceCheck and rank the quality of the OSM road data in 51 cities throughout the

US. We started in 2018. We analyzed the road data for all the cities, we ranked them, and we published the data and our findings on OSMquality.io. Building off from that 2018,

2019, you probably see us hopefully every year, we started looking at the trends and trying to understand if there is anything we can bring into the US community and make our road quality into the next level. And that's what we're here this year. Before let's jump into the data and

see a lot of cool things, that's kind of rollback for a little terminology. So when a mapper is actually mapping the map, what we care is, hey, let's make sure the road is connected and make

sure the points was actually accurate, make sure the polygon is not broken. But when the computer it thinks a little differently. Other than the road network completeness, it's actually looking into the connectivity, it looks into the speed to more attribution. There's a one-way,

there's a reversible one-way, tons of things, turns, access, a lot of restrictions. Having a map complete is definitely everyone's dream. But having a network complete is more important right at this modern stage where everyone actually using a routing at some ways

for the wayfinding from point A to point B. In order to call out this attention, we want to roll back and see if the road network complete

in US or not. We look into 2018, we look into 2021's data, we find out there are eight cities are having a drastically great improvement on their map errors, dropping like 200 from one check. That's incredible, right? For just one city. There are still 18 cities are up and down,

there are definitely a new road creations, the new constructions, and there is something that's still being worked on. But what's more important is there are half of the US cities are actually quite stable on the trends. What does that tell us is we believe that almost

every cities, a lot of cities in US, when they create the road network, they know the importance of the completeness of the road network. There are actually less and less map

errors introduced when the road actually being modified or there's a new road creations. But does that's enough? Does that actually equals the zero routing errors? In order to find out where those routing errors are, we're using a sync island checks from

Alice Czech as the illustration today. What's sync and what's island? The sync is a kind of a code name where think about yourself driving on the one-way direction,

you can only drive on this direction and unfortunately you're hitting at the end. You're actually sinking into that end. On the other hand, the island is you wake up and you're starting to driving from one road, but the routing engine tell you there is no way you can get out of here. You're just stuck in an island. We don't want either of that.

And if you use the search and then you see that on your app, you're like, you don't trust that app anymore. Believe me. That happens to me and that's how I feel.

Let's take a look and connect that concept to what's the real things in the OSM. If you're on any of the one-way service roads right here, and unfortunately this is a sync air, you will route yourself into that red stop sign right there where

it's access equals to private. The routing engine generally tell those private role are not allowed for public routing. And then it is just going to going for nowhere, unfortunately.

On the opposite side, if you are the residents on the building one or two, and you park your cars in the service roads, that's right there. Because all of the connecting road segments are tagging equal with assets equals private. The routing engine say, okay,

those roads, I don't want to route any public user to it. What does that mean? Well, you kind of just stuck there and you cannot really get anywhere but stuck here. Those are the things when we're doing the routing, we're trying to avoid.

And we also want to see how many of those issues happens in the US between 2018 and 2021. But 2018, we were seeing, okay, for a city, the maximum is 120 failures.

It's bad, but it's not that bad. We look at 2021 and we're like, oh my goodness, there is one city like creates over 650 map failures for just the same island. And worse than that is if you're actually use that a high bar in 2018,

you're actually seeing actually a lot of cities are passing that lines. We also look at different angles, we're trying to figure out are those all service roads. So we have an investigation, 69 map errors are derived from the service roads in 2018,

which is high, but it's even higher in 2021, 87% of map errors are service road. What does that lead us to believe is there are a lot of service road being created over the

course of four years, and they are actually introduced the map errors at the same time. We actually graph this and my team work on to figuring out how many service road being created over the course of years. You can see thousands of roads being bootstrapped,

being complete. The US mappers are working super hard that you can see that from the number. But we're also seeing a decent amount of the map errors, especially Sinkin Island errors created here. There are roughly every 3000 service

road being created, one Sink Island map errors is found, roughly 0.39%. And if you only look at the map error counts, it's not a fair observation because if you see

Dallas, they actually create so many roads and their error rate is actually around 0.39, not very far from the average US cities. What this tells us is we also want to urge the community when you're actually working on the road creations, that's actually take

even close look and make this quality even better in 2022. If you're interested in running more Alice checks to know your roads, to run your road cities, please contact Chad or Todd and we're definitely happy to help

and definitely check out our website for the previous years. Thank you very much.