UPDATE 12/28/16 : The Venetian Causeway permanently re-opens to all motorists, pedestrians, and cyclists.
This is a big safety concern for cyclists, runners, skaters, pedestrians, and scooter/moped drivers alike who use the Venetian Causeway as an alternative to the other thoroughfares. The Venetian Causeway is the most popular route among non-motorists due to the slower speed limit (30mph), adequate bike lanes, less motor vehicles, and smaller bridges.
The MacArthur Causeway (though not a great option) is still a better alternative to the Julia Tuttle (I-195). The speed limit is 40-50mph and there are several intersections along the way which slow motorists down slightly. However, we still suggest riding on the sidewalk on both bridges (unless riding in a group), there is no shoulder on the easternmost bridge so you're basically riding on freeway. Not for the faint of heart.