I've googled it but the antonym of mass-transit (or public transportation) are not amongst the hits I've got.
I can explain the meaning using a sentence but I'd like the correct term, a noun if possible.
"Going by car" doesn't suffice because buses are, technically speaking, cars too. "Private transportation" seems to be wrong, because it could be publicly available. "Individual-transit" excludes co-commuting, so it's not right, neither...
The context of my question is getting oneself to work, so commuting scope. Taxis, planes, helicopters, submarines and such are very rarely used for said purpose, so they can be excluded. Bicycles, skateboards, pogo sticks etc. are muscles driven and can be equated to walking which isn't within the scope of getting to work by other means than by "one's own machine".