Any annoucement including a blog post or company/verifiable employee social media post is fine. Time ends at 00:00 on January 1, 2024, Pacific Time. Note that this market depends on a public announcement, so it still resolves to NO if 7 million miles are announced in 2024 even if those miles were achieved in 2023.
(Note that driverless miles are NOT the same as self-driving miles. The later includes safety driver miles)
https://waymo-blog.blogspot.com/2023/12/waymo-significantly-outperforms.html?m=1
"Waymo significantly outperforms comparable human benchmarks over 7+ million miles of rider-only driving"
Over 7 million rider only miles definitely means no safety driver to me.
Cruise should be at around 5 million driverless miles now or soon, pending public announcement: https://manifold.markets/zzlk/will-cruise-announce-5-million-driv. CEO Kyle Vogt said they were on pace for >1M driverless miles per month, however that was part of the 4 million mile announcement which was 38 days ago (more than a month ago): https://twitter.com/kvogt/status/1690050803283922944