You need the PFF Editor to extract the 3di's
https://novahq.net/files.php?ID=60
Check in the localres.pff file for the 3di's
Then convert them from 3di to obj files to import into your 3d program.
I used MilkShape in the past to convert them, but have been given a test converter to do it for me. If you like i can convert them for you and send them to you.
Now depending which way you want to go, import into BHD or import into another game?
If you import into BHD or such you will need to add collision boxes (CB01) to your model. Also you will need to add the information if a bus, like wheels to turn in the OED