[bobthepanda]

It is worth noting that part of the reason it was so cheap was because the government had already purchased the required land for a freeway. Land acquisition, as many infrastructure projects like CAHSR or Texas Central can attest to, is easily some of the most costly and risky part of these projects, even if you do decide to use eminent domain.

BRT has notable disadvantages; buses can move from side to side unlike rail, so the tunnels and bridges have to be bigger or use proprietary guided technology like this one. In general road surfaces wear away much faster than rails. And rail vehicles perform much better once you factor in labor costs. BRT is useful in some cases, like where there is no dominant trunk line and buses can leave the roadway to serve different destinations; but eventually the common trunk gains enough critical mass and you convert to light rail anyways, as Seattle and Ottawa have discovered, and LA is considering for the Orange Line BRT.

[Declanomous]

BRT would actually be amazingly useful in Chicago because a massive number of people commute to central business district (The Loop).

Chicago owned all of the land used for the Loop link and it still cost $41 million, and has little of the benefits of actual BRT.

People here get incredibly upset when any road diet is discussed. Our politicians rarely ride public transit, and laws and engineering guidelines prevent projects which would reduce the volume of traffic carried. It's absurd.

[bobthepanda]

It costs a lot to modify an existing street vs build a brand new road, mostly because you have to modify drainage (Loop Link had concrete boarding platforms in the middle of the street that certainly would've disrupted existing drainage), bring the street up to modern standards, and keep the existing street open during the work for all the buildings that front it. It's really not all that simple.

In fact, the fact that it was on an existing street would make it very expensive to modify; look at a picture of the O-Bahn and there's plenty of space for construction vehicles and staging to set up, no one to get in the way of, etc.