We can congratulate GM for this milestone but they should have been making this change on their whole line three years ago. Back in the 1960's all the car makers offered a highway version of their cars. Most of the reviews I saw on some of these cars over the standard version was 3 to 6 mpg at highway speeds. I remember a friend of mine who's family had a Dodge Colt back in the late seventies that had a T-shifter you pulled while on the highway to engage an OD. They need to bring back the highway option since many people have moved several miles out from many of our major cities.
Most of the cars on the road today could easily get an additional 4 to 5 mpg with the availability of a highway option performance package.
I know both my cars came with middle of the road gearing. It isn't the best for off the line performance but it also isn't the best for highway running either.
At least the one I was able to swap out my rear gears at a relatively affordable price. The new Highway car is being a bigger pain than I thought it would be to get better highway gearing for.
1967 Oldsmobile Turnpike Cruiser