I'm still confused
you say he could park his old cab either "anywhere on the street", "in front of his house on the street",
"the other side of HIS driveway" or "on the equally empty side of HIS driveway"-am I understanding that your hoop entails your kids playing basketball on a portion of his property/driveway? or that they throw from your property but the hoop hangs over his?
if that's the case, despite you having an incline on your driveway that prevents you from having a hoop that's self contained (including use) within your property-while you might not like the neighbor parking his work vehicle there (sounding like it's a portion of his property vs. the public street)-unless it's prohibited by your zoning laws-it's well within his rights, and even if it's prohibited-he would still have the right to block acess.
And as an aside-where we lived we had an adjacent neighbor who chose to put one of those free standing hoops on the street (next to the curb) but rather than being directly in front of his home he placed it on the small chunk between our two homes that once it the sidewalk ended we owned 9/10th of.
it caused not problems for him, but for us it caused all missed shots to end up in our flower garden, over our back fence, rolling around in our driveway...and despite his kids rarely using it-other kids who roamed at night took great joy in shooting rocks through the hoops (that hit our house and car), and using their weight to knock it over into the street blocking our driveway. it wasn't until a couple of windstorms knocked it over-once into a city vehicle driving by, and another time into the path of the garbage truck (they ceased pick up for the entire street until the thing was removed) that he was forced to move it (subsequently an entire ban was put upon unless they were placed entirely on private property and a designated distance from any adjoining property lines).
before I went calling in suspected code violations for parking, I would be looking to weather I was acting within current code, and more so-simply assuming my neighbor is accepting of me/my kids utilizing HIS private property without his permission.