If you run the NAM installer (even if you've already installed it, you can re-run the installer) and select "Custom Installation", there is a section near the bottom named "Road Textures and Markings". In there, you can find the "Asphalt Textures for Maxis Highways" option, which I believe is what you're looking for. There's an image to demonstrate here. Hope that helps
@kschmidt: Draggable Fractional Angles have been experimented with for some of the other networks over the years, but we've never found a satisfactory implementation for the dual-tile networks like Avenues. I would guess that FLEX pieces would be more likely if/when were were to implement that functionality.
As far as the old versions go, they have fewer features, and the newer versions have fixed problems with them, so there's really no reason to use them. Our primary focus is always the development of a new version. All that having old versions around would do is confuse people and create completely avoidable technical support issues, which would take time away from development.
Edit: Also, since the FTP upload is down, we have temporarily re-routed the Download button on the STEX upload over to the registration-free mirror at ModDB that Cyclone Boom referenced. Apologies again for any temporary inconvenience--we hope to have the direct download restored soon.