Back in my HAZMAT study days in the 80's, looking at the continental gasoline pipeline-to-fuel-farm storage tanks, it was all unleaded gasoline, diesel, heating oil, period. AVGAS, JP-4 and 5 was routed out to the bigger airports on a separate leg to those storage tanks and anti-icing adds are added there.. For MOFUELS, additives, detergents and octane boosters were added at the head the delivery truck loads from at the Farm. Shell has a loading head, Texaco/Star, Mobil, they all have their own and did their adds straight into the transport truck. Now, that was in the mid-eighties. Curious I am these days at what point straight gasoline becomes E-10. Does E10 come up to the East Coast through the continental pipeline, or at the destination-end, the storage tank farms?
My Hyundai Touring SE gets brand name, but plain old regular 87 octane, mostly Mobil regular. There are very few Shell stations in New England off the interstates. New England seems to be very Mobil-Centric with a smattering of Sunoco and a fair number of Gulf stations, dealing, presumably, Chevron product. There are a few Citgo stations, but until the seizure of Citgo stations in the U.S. to cover the defaults down "there", I avoid Citgo just because. The rag-tag no-names I pass em by, again, just because.
A curious thing I do see everywhere is folks gassing up plain old non-turbo econo-boxes with high test, to me, a pointless waste of dough unless I'm missing something? The stuff being 3.45 a gallon vs. 3.20 doesn't seem to deter them, either..