Moscow still has huge traffic jams at rush hour and, according to TomTom, a Dutch company that compiles an annual survey of global traffic conditions, is now the world’s fifth most congested city. But this is a big improvement over just a few years ago, when Moscow beat out Mexico City, Bangkok and other notoriously congested cities for the title of the world’s worst traffic. This progress, said Mr. Polyakov of the city’s Traffic Control…