The Kodak traffic surveillance films have been discontinued for some time now, but have long shelf lives. They are t-grain emulsions on an Estar-AH base, which makes them different from both 400-HD and Portra 400. I have used a quite a bit of both 400HD and Portra 400. They are reasonably similar, but 400-HD has higher saturation. The higher saturation makes it appear grainier than the old Portra 400NC, although it isn't. Both had pretty severe grain in 35mm, although acceptable for most uses. I decidedly preferred Portra 400NC. The current Portra 400 is a quite different film, with considerably less grain.