[Tagging] TRAVEL_DIR (and other fields) in shapefile?

[Matthew Woehlke]

This might be somewhat OT, but it's OSM-related, so...

I have a shapefile I obtained from a county's GIS¹. In addition to road 
names (sometimes) and speed limits (yay!), there is an attribute 
TRAVEL_DIR, which seems to have the possible values (at least) 1, 2 and 
3. Does anyone know what this field means? (I was hoping there might be 
some indication what roads are one-way, but I have not been able to 
determine a definite relation.)

For that matter, is there other useful information I might be able to 
extract? (For example, I wonder what TYPE_CODE means...)

I'm sort-of hoping these might be using some US standard system and not 
something the county made up. There seem to be some indications of that 
from trying to search the internet for information, but I was unable to 
find any sort of legend.

(¹ https://gisdata-pwcgov.opendata.arcgis.com/datasets/roads)

-- 
Matthew