Bridge Across the Ocean

The bridge would be pontoon bridges pre-made from giant injection-molded plastic units a kilometer or so long, manufactured on the coast and then towed out piece by piece. At 100 or 500k intervals there would be a section that opened to allow ships to pass, and then closed itself back up (not drawbridge-style, but releasing at the joint; one bends left, one bends right, the ship passes, and motors on the underside of the pontoons move them back together and they re-lock).

Benefits: Increased individual travel. A shinkansen style rail system would probably be best – faster and cheaper (even across the Pacific, two days from California to Japan; but if the goal is to link the Old World and Americas, probably makes sense to build it Ireland to Newfoundland, Canada). Even in a petrol bus a San Francisco to Tokyo round trip would be less than $200. Driving through the night at highway speeds you could make it in four days.

Savings at intermodal yards. Lorries’ freight don’t have to get loaded onto ships; they just take the exit for the pontoon bridge.

Environmental: The bridge could be placed where the Pacific trash pile collects (and where others collect in other seas and oceans). The bridge could provide some of its own power itself if large quantities of solar cells are placed along it; might even feed into the grids of neighboring countries.

Emergent problems to solve: Driving across the ocean would ironically be tantamount to driving across a 10,000k-wide desert. If rainwater collected along the length of the road isn’t sufficient water for motorists, desalinization plants

Waste – would probably be most economical to have isolated septic tanks, and a vehicle to service the rest stops with a vehicle emptying them, rather than building plumbing to go all the way across.

Law enforcement and rescue – such wide spaces would be difficult to patrol (ask the Australian police).

Storms – the road would have to close if there was a typhoon threatening along the length of the bridge.