The document doesn't say either one. Do you have other documents that make the distinction?
It's not entirely conclusive, but if you look at the case record (posted at the link) for the car accident case, you'll see that the address for the Freddie Gray in that case was 3601 Dudley Avenue. Now, here is a case record for a case involving Freddie Gray Sr. in 2008:
Note the address: 3601 Dudley Avenue.
Now, here is an arrest record for Freddie Gray Jr., at around the same time:
Note the address: 414 E. Lorraine Avenue.
And, for good measure, here's another Freddie Gray Jr. arrest record, from 2007:
Again, the address: 414 E. Lorraine Avenue.
So, taken together, the case involving the car accident invovled the Freddie Gray who lived at 3601 Dudley Avenue - that is, Freddie Gray Sr.
Once again, this "fourth estate" site is full of crap.
It may not be conclusive, but I think it's beyond a reasonable doubt.
Nice catch... thanks for the follow-up.