You know the place: a Neorealist set populated by the young and the restless and the dazed of all ages, all living with the omnipresent but hard-to-grasp specter of kitschy/deadly communism yet steamrolling into the ruthless capitalist future. Yes, “China” has become a subgenre of contemporary documentary, as Beijing Taxi helps to confirm. Shot on HD as the 2008 Olympics approached, Miao Wang’s portrait of Beijing is partly a look at three average cab drivers—a mom who likes the job’s independence, a sickly Cultural Revolution vet, a jolly complacent fellow—and partly glossy travelogue, with skittering footage of city folk, buildings, and the odd ceremony that tilts perilously toward lux B-roll. There’s something transformative goin’ on in the streets, no doubt, and Soviet kinetic-kino pioneer Dziga Vertov might have liked the film’s ethos of a nation on the move. But, especially with Chinese pop smoothing the way, Wang’s letter from Beijing feels too breezy and light on fresh insight. The highlight is the crop-cut woman of the group, Wei Caixia, resoundingly vivid in her mix of ambivalence and confidence and worth her own film. Why not this one?