The mission was made easier in one of the updates - so I suggest that the OP makes sure that the game is currently updated [if you always have your console connected to the internet, it should be fully updated - if you never have, please connect it and the game will prompt if there is an update]
Even though many never had an issue with the chase before the patch, some did, which is why we had that update..
Best advice has already been posted - best to think ahead and try and cut the distance down.
hmm... okay, let's try. "R1" on Playstation is the "notorious button", which is the button you use for running, or, for a funniest description, when you stand still and hold it, Connor makes a weird move, like preparing his body to do some action. The "O" is the button we use to make interactions in the environment, such as starting a riot or opening doors, and the"X" is the one you jump or fast walk, but I really think this wasn't necessary and you could eventually find them by yourself. xD