Saw someone had replied to you on the SCS blog about Denver's REALLY stressful/bad traffic, and I figured I might as well explain why its so bad as a local.
So here's a map I just threw together of Denver's roads which shows Denver's highway network.
Blue roads are definitely highways with no stop lights, and essentially built to Interstate standards
Green are tolls, so lots of people avoid them
Red SOMETIMES act as highways, but have lots of stop lights and intersections. They essentially act as funnels to the Interstates.
now compare this to a city like Dallas, or literally any city east of the Mississippi, and the differences are obvious. The ring roads are only on the VERY edge (and not even fully looped), so their purpose to act as bypass traffic is essentially defeated because they're some of the only toll roads, so people don't really use them much, so people either use local roads, or just go onto the interstates.
I25 sees TONS of traffic. Basically the way the road network is constructed, if you wanna go anywhere you have to get on I25. And I25 is as wide as it can realistically be already, and still sees huge traffic jams. They built a train line along I25 south of Denver to try to help ease traffic, but its still horrendous, and now people are just packed like sardines on the trains.
Also tons of the existing infrastructure is REALLY old. In downtown Denver, driving along I-25, they still use mostly original bridges, in the part of the highway that sees by FAR the most traffic, so they're really falling apart, and just not designed for 2020.
This all boils down to Denver NOT being built to support the population it does now. More and more people have to live further and further away to go to work, so traffic just gets worse and worse.
Heck, Colorado Springs is basically just a commuter suburb of Denver now. When you see a place like THIS, https://goo.gl/maps/Kc7yzdbjVpWHDJy56
you wouldn't expect to see a massive traffic jam EVERY day, so you'd just built a standard 4 lane interstate. Flash forward to now, and that 4 lane interstate in rural nowhere is causing HUGE headaches, and they're trying desperately to expand the highway, as more and more people keep flooding in making things even worse.
So long story short, Denver has REALLY bad traffic issues, because Denver's road network funnels people into only one or two large interstates, and people have to travel further and further distances to get to work, so I25 and to a lesser extent I70 are just getting worse and worse.
sidenote: the large green areas on the map, Rocky Mountain Arsenal and Rocky Flats are not just big nature reserves in Denver for no reason. They're old nuclear/chemical weapon sites, and are so contaminated its impossible for any person to live there. They aren't just room for potential expansion, they're our reminder that some stuff messes up the earth permanently, and you just loose large parts of your city because of it. Denver has a really dark history of manufacturing horrible weapons, and we have the scars to prove it.