Beware the MacArthur Causeway. It's disguised as a six-lane highway that connects downtown Miami and South Beach across Biscayne Bay. But drive it enough times and you'll know it can warp time and space to its will, transforming a simple three-mile trip along the shimmering blue-green bay into an hour of white-knuckling the wheel. When it was completed in 1920, a handful of lanes was probably all that was needed to efficiently accommodate folks looking to shuttle across the bay. Now it's a sea of brake lights. Avoid at all costs. Detour to the Venetian Causeway or Julia Tuttle.