Transport in northern Japan is slowly staggering back to its feet, so I figured it'd be good to have a separate thread for tracking the situation.

Airports

As far as I can tell, all airports except Sendai are operating normally. This includes Fukushima, Iwate-Hanamaki, Yamagata, Odate-Noshiro and Mizawa. Sendai is currently used for relief flights only, no reopening date set yet.

Trains

All major train lines in Tokyo operating, but many running reduced schedules and some special services, notably Narita Express, not operating.

In Tohoku, west coast services are operating normally and local services in the north up to Yonezawa and Ichinoseki will be restored by 3/20. Akita Shinkansen between Akita and Morioka already open, Tohoku Shinkansen from Aomori to Morioka to be restored by 3/23. Map of exact opening schedule, which (based on the URL) will be updated continually:
http://www.jreast.co.jp/pdf/saikaijoukyou.pdf

Still a huge gap in the network between Nasu-Shiobara and Ichinoseki, with eg. every line connected to Sendai entirely out of service. JR East has published a "U-turn route map" showing ways to access many towns with a loop via the west coast, with some gaps covered by bus:
http://www.jreast.co.jp/pdf/ukairoute.pdf

Road

Expressway info from E-NEXCO: http://www.e-nexco.co.jp/
Map view, closed roads in black: http://www.drivetraffic.jp/map.html
Status as of March 18: http://www.e-nexco.co.jp/pressroom/p...ice/h23/0318b/
Map as of March 18: http://www.e-nexco.co.jp/pressroom/p...b/pdfs/112.pdf

Note that many of the sections marked "closed" are, in fact, open to emergency and supply vehicles, and all major towns in Tohoku (incl. Sendai) are accessible by public bus.