This is a shot of the Pineda Causeway from a boat launch just North of the Pineda Causeway in Palm Shores Florida. Across the Indian River Lagoon, you see Merritt Island, and then the second leg of the Pineda Causeway that spans the Banana River.
Unlike many causeways in the area, the Pineda causeway has no street lights on it. This is because of its close proximity to the runway at Patrick Air Force base. In fact, if you continue over this bridge heading east toward the Atlantic ocean (only a couple miles away), you will see the Air Force Base on the north side of the road.
The Pineda Causeway is the furthest north river crossing in the Melbourne / Eau Gallie / Palm Bay area. About 5 miles to the south is the Eau Gallie Causeway, but the next causeway to the north is 520 in Cocoa about 25 miles to the north. There is no other way out to the barrier island between those two points.
These causeways are vital links between the beachside populations and the rest of Florida. However, these causeways become unsafe when winds exceed 45 miles per hour during large storms and hurricanes. After these storms, the bridges are usually closed and inspected, but they open back up rather quickly. For more info, check here.
In the early days of settlements along the Indian River, the beachside communities were only accessible via ferries. Later swing bridges and drawbridges were built. Eventually these large causeways were put in to allow passage of traffic and boats without either disrupting the other.