Waymo ( and self driving programs as well) have been careful not to go for public large scale deployments in any city with difficult weather and for good reason focused on cities like Austin, Phoenix, Los Angeles, SF[1] so far with easy driving weather.
There have been promising progress and there have been hints of a New York trial soon, but it it well known that self driving cars have not done large scale trial in cities with bad weather.
[1] Yes, I am aware SF gets a bit of bad weather with fog and rain but not nearly not as much to make driving quite unsafe like somewhere that gets a feet of snow in 24 hours in winter, and likely promixity to engineering HQs and favourable regulatory climate influenced the SF choice.
They only compare to human accidents in the areas they operate. It doesn't matter where they don't operate today as they don't try to include human crash numbers from those cities either for the comparison.
Every time someone thinks this is some gotcha, but it isn't. Their methodology clearly attempts an apples-to-apples comparison.
There have been promising progress and there have been hints of a New York trial soon, but it it well known that self driving cars have not done large scale trial in cities with bad weather.
[1] Yes, I am aware SF gets a bit of bad weather with fog and rain but not nearly not as much to make driving quite unsafe like somewhere that gets a feet of snow in 24 hours in winter, and likely promixity to engineering HQs and favourable regulatory climate influenced the SF choice.