They mention HOT lanes. I need to see exactly where, and what time of day they used to get their stats, because I can tell you, HOT lanes don't do shit if you allow carpoolers on for free. The idea of the carpool lane is a nice thought, but in reality it's a joke.
Any time there is actual "red" traffic (as you would see in Google maps), the carpool lane(s) are just as backed up as the rest of the traffic. The only time I've seen moving traffic alongside red traffic, is from a pure toll lane alongside a regular highway, like The 91 FasTrak lane. And even STILL, those lanes can be backed up during peak times.
Ask yourself, who uses carpool lanes? Carpoolers? Hardly. It's mostly families, who will be on the road anyway. Then you have work vehicles, who naturally have multiple people, and the ever annoying buses. My point is, the vast majority of those who use carpool lanes were going to be on the highway anyway. There aren't people saying to each other "hey, lets carpool so we can use the carpool lane and get places faster". Even if for some reason we decided to start doing this as a society, we would then realize it's bullshit because the carpool lane just doesn't work.
Here's an idea: 1) set up cameras or road strips at several places along problem highways 2) create a computer model using the traffic data 3) try out road configurations using this data until you find something that works really well. Or at least, use the traffic data to identify what's actually causing traffic problems.
My guess is most of the time it's the shockwave effect from bad or desperate drivers. It happens to all of us, even the experienced drivers, where we suddenly need to get off the highway and we have to cut off people, which inevitably results in a shockwave effect. Adding lanes isn't going to help this, in fact it will probably hurt this particular problem. And now think about this problem combined with carpools, where at least here in SoCal, don't let you get off when you want. So now you are in the carpool lane, unable to get off, and finally when your offramp is 1 mile away you are able to get off, what are you going to do? You have 3+ lanes of traffic to get over. Good luck and please drive nicely!
When I see these giant highway structures built for a single carpool lane [1], it really depresses me. How did we allow it to happen?
[1] (two lanes, one for each direction of traffic) https://www.google.com/maps/@33.6871144,-117.8750226,97a,20y...