A well known transportation academic posed this question recently to other transportation experts.
Failure he said. You decide the criteria. Failures could be big small, but not too small and localized.
I am looking for projects, systems, technologies, or policies that have been failures.
To provide a response in a general way, I had to define failure in a general way. So I defined it as “the usefulness of a transportation mode or infrastructure to my adult life and the quality of it—the mode with the least usefulness would be a failure.” Here’s my assessment looking back in the last 30 years which also coincides with the length of my adult life, more or less.
Roads and cars allowed me to access everything that was out there… people, sights, activities, opportunities.
Roads and buses let me travel intra- and inter-city when I was making little money.
Roads, bicycles and mopeds made college life much easier and efficient. The bicycle as exercise on public roads and bikeways is among the least demanding and most enjoyable. It works for me.
Airplanes took me the world over. Nowadays, large airports like Incheon in South Korea allow me to get to Asia in one flight from the US and then the rest of Asia is one flight away.
Helicopters allowed me to study the main freeway in Honolulu and observe traffic shock waves in action. They are the best mode to view volcanoes in Hawaii and among the best means for rapid rescue the world over.
Bridges and tunnels. All had an obvious utility in time savings and safety.
Small ferries took me to islands with my car, large ferries took me to countries with my car, and container ships got me food, TVs, furniture and cars. Tanker ships bring oil to fuel most of the transportation I listed above. I love fish, so many thanks to the global fishing fleets and their harbors.
Freight trains. Without these trains and coal the US would not enjoy the cheap power it used to propel it to a global dominating status and the highest standard of living. Their indirect effect to my well being has been substantial.
Cable systems and telepheriques have a practicality all of their own and once built they are not too expensive to operate. The alternative, if one exists, is typically a long drive along narrow, winding and occasionally icy roads.
Passenger trains. There was always a substitute and they never were a necessity. I took the TGV in France, Shinkansen in Japan, and China’s fast trains. Without exception, all of them were one way trips, just to try them out. All of them were expensive and difficult to handle with two suitcases. They were much more crowded than airplanes. I also use metro rail in Europe and Asia, and in a handful of very large cities in the US chiefly because their downtowns are devoid of parking and their bus systems are too complex to learn in a short visit.
Thus, in relative terms, rail systems have done too little for my life experience and quality of life, thus, almost all rail systems built in the last 30 years were a failure. Add to this that all but Shinkansen are constant loss-makers and their first place as modern era transportation failures is assured.
ENDOTE
One maybe tempted to say that my response is skewed because Honolulu does not have rail. I've been in Honolulu for 22 years and my residence and work locations have been in a triangle formed by Kalihi, Kailua and Kahala. Rail would not be useful to me.
I spend a lot of time in Athens and my brother, sister and their families reside there. Less than 1% of our trips use any of Athens' multiple rail lines. For most people, a rail line makes no difference in their 21st century life style.