The part about political accountability made me kind of chuckle.

> The PP candidate for Assembly President, Alberto Ruiz-Gallardón, promised to deliver 30 new miles (48 kilometers) of metro by the next election, compared to the 14 miles (23 kilometers) the PSOE had delivered during their previous 15 years in government. With this pledge, the PP won a majority and Ruiz-Gallardón was duly elected president.

It's hard to see that working in the US, even if we eliminated the jurisdictional patchworks, because what will happen is one candidate will promise 1000 miles and the other will propose destroying existing infrastructure, but they'll also make competing promises on homelessness, affordability, and various culture war issues, while jockeying for supremacy in media prominence, and then whichever one gets elected will build 0 miles and say it was somehow the other one's fault. It's just hard to imagine any sizable electorate in the US actually voting based on an issue like how quickly and cheaply public transportation is built. If we had the kind of people who care about stuff like that, we wouldn't have the problems we have.