On the Air Traffic Control system Command Center web site for Preferred routes. It ask for Route Type. The types are L,H,LSD,HSD,SLD,HLD,TEC.What do all those mean?Bob Johnson Sr. (KMIE)

All I know is that "H" is for HIGH altitude rotues, and "L" is for LOW altitude routes. That should be all you need.

Thank you.Bob Johnson Sr. (KMIE)

L LOW ALTITUDE H HIGH ALTITUDE LSD LOW ALT SINGLE DIR HSD HIGH ALT SINGLE DIR SLD SPECIAL LOW ALT DIRECTIONAL SHD SPECIAL HIGH ALT DIRECTIONAL TEC TOWER ENROUTE CONTROL Regards.Ernie.

Hey Ernie,I have looked all over the FAA's website in the AIM and ATC contractions list and I could only find TEC. Is there a location where there is information about these different routes that you know of? I would be interested in finding out more. Take care,C.J. StarrPPL, Instrument Student