Aggressive driving and dangerous driving are usually considered to mean the same thing. If someone drives aggressively, it means that they drive in a reckless manner, such as speeding, tail-gating, excessively changing lanes, or improperly passing.
Dangerous driving basically means the same thing, although this term seems to be more common in British English than American English, especially as a legal term.
So, I agree with you. They basically mean the same thing.
