Hi,
Great question, thanks for sharing.
Here in Oregon, ODOT has created more detailed SPFs for driveways on highways. This is part of a move to include better safety evaluation as a part of access management. I don't recommend using this directly, but it does provide some information on how you might approach a similar topic in your location.
The report is online here:
http://www.oregon.gov/ODOT/TD/TP_RES/docs/Reports/2012/SPR720_Driveways.pdfThere is also a spreadsheet available that automates these SPFs, but I am not sure exactly where to find it. Sorry.
Hope this is helpful,
Ben.