Reuters is where I usually go for news, from this side of the Pond. Their "sources familiar with the matter" are now saying that it was caused by reckless driving. That was as of 10:41 PM my time.
The things that everyone agrees on are that there were 2 people in the car and both are dead, and the border guard in the booth at the checkpoint suffered injuries that were non-life threatening. Also, that in addition to the Rainbow Bridge, three other crossings are closed, and Buffalo's airport is also closed.
https://www.reuters.com/world/us/exp...es-2023-11-22/