Giuliani was a passenger in a Bronco driving on I-93. As they neared state police attending a domestic call on the other side of the highway, they were rear-ended and the cars ended up on the median. The state police walked over to help them. Giuliani's spokesperson Ragusa told a different story.
The only way the conflicting stories could both be true would be if they drove one way on I-93 and called police, police arrived, then Goodman and Giuliani happened to come back later on I-93 going the other way. Either that or they're making up the part about the woman flagging down Giuliani.