The Nav does take traffic into consideration, and may re-route you after your start. Only about 1/2 of the time is the re-route beneficial.
Last weekend after charging at Burbank, (4 cars waiting), I got a routing to go side-streets to the 210 freeway, then to down Orange grove to the 110 freeway through downtown LA to the 5 south. Well after getting down orange grove it re-routed me to do a 180 back up orange grove to the 210 and eventually to the 215 S. through Temecula.
I gave up and finally just took the 5 south and fought the traffic. Long drive!!! I think I would have been better off just getting on the 5 from Burbank in the first place. I don't believe that it takes into consideration that you have access to the HOV lanes, and that regular reported traffic may not impede you as much as those outside of the HOV.
A toggle to disable re-routes should be added IMO.
There is already a toggle. Controls/Settings/Maps & Navigation/Traffic-Based Routing. Turn that off because it will drive you crazy until they fix it and give you route choices.