There are several tweaks on the typical diamond and cloverleaf intersections floating around. Diverging is one - though it freaks people out having to drive on the "wrong" side of the road. And Glenn Hwy in AK took some damage in the earthquake last week - how did the new interchange do?

A modified version, which mainly just brings things to a single signal rather than a group of them, is on Eucalyptus at I-215 in Moreno Valley. Not too confusing. [www.google.com]

This is nibbling on the edges, improving localized traffic flow but not dealing with the amount of traffic overall. It's worth doing, but in the great scheme of climate change it doesn't really matter.

I took chemistry, and atmospheric science, as part of a liberal (not liberal arts) education (but not engineering), so I understand what's behind some of Bob's rants. The math is fairly simple, in principle: starting from a relatively stable situation for some thousands (closer to 10K, since the end of the last major Ice Age) of years, we as a species began dumping, mostly since the early-mid 1800s and especially since WW2, fossil carbon into the atmosphere in the form of, mostly, CO2. CO2 is well known (since the 1800s) as a greenhouse gas - it traps infrared much like glass in a greenhouse, quite effectively. So it was qualitatively obvious even in the 1960s that as the stuff built up (sinks for it work quickly only from a geological perspective, and there are unpleasant side effects such as warming, acidifying oceans) the atmosphere would warm. Detailed models of how it would evolve were only feasible, though, once we got powerful enough computers and more data in the 1990s and later. So yes, human-driven atmospheric warming is happening, we have a pretty good idea now of the consequences and approximate timing, and things should be done about it if we don't want to lose much of what we now call civilization over the next couple of hundred years. However, it's turned into a politico-religious war dominated by extremists, mostly but not entirely on the right. It would be reasonable to do a number of things, including a rail system that can replace some road trips so we don't have to build a lot more roads (rail would actually be cheaper for a decent capacity and service level if done right (220mph HSR is probably not something that a 3rd-world country like the US should be trying, but there are other options)), because rail is simply the most efficient form of motorized land-based transport. Nobody's saying, though, that we have to go back to mules and trains and a life that's nasty, brutish, and short (unless responses that greatly reduce emissions are avoided too long); technology and (one might hope) society are better than that now.