TMC data comes from variety of sources: official and users. Traffic control in your local area uses camera to monitor conditions, look at schedule for constructions, take reports from police and road services. Users can also report such info. It's up to NNG server to processed those data. Different product handles internet TMC differently (ie: Waze)

HSP are dynamic data not static from map. The construction example showed that "real speed" depends on users experienced/collected data. I never said that the speed didn't depend on other factors such as congestion or based on time of day.

I can't test HSP because 1) I try to avoid traffic and 2) I drive during off hours (night shift). Various route options are available via default skin. I don't see much different in where I drive so I can't comment on its usefulness.