Folks have made it as far as the shrimp farm in the Basil Jones area.
The "road" pretty much ends just a little south of Habaneros. At low tide it is possible to go farther north, but not recommended.
I usually take a drive from Costa Maya 6.5 miles north to a spot just past Blue Reef about 8 miles north.
A 6.5 mile ride will take you aprox 1hr., 1-way.