Is that different than an environmentalist? I don't know, but his PhD in chemistry certainly separates him from Meadow TreeHugger. Newman, like many of us, long ago realized that humans and our greatest invention ever, cities, are both problem and solution to potential environmental crises. I don't even care if you buy into Peak Oil Theory or Climate Radicalization, what IS significant to every person with half a brain, is his use of the Marchetti Constant, which Newman simplifies to the "one-hour city."
What this means is that no matter the city (and here we're using "city" to reference the physically interconnected and interdependent economies that comprise a metropolitan area), it will always be 1 to 1.5 hour across. Transportation format is irrelevant, except for costs (both tangible and intangible) to taxpayer, user, and what we might as well call administrator/caretaker - usually the government.
Newman also shows that there is no relation between highway building and commute times. The city adapts to a dominant mode of transportation and expands or contracts accordingly. Make everybody have to get into cars, we spread out until we're an hour (or so) across.
Building strictly for cars is therefore 1) useless and 2) dangerous. He also talks of collapse. And if you know anything about the collapse of complex systems, you know that the chance of such an occurrence is greatly increased in monocultures, ie not terribly complex systems. Car-centric world is not complex.
It can be called Generica precisely because of this lack of complexity, its oppressive sameness. Its future is limited by and tethered to the volatility in oil prices. The larger implication for land now sat upon by McMansions rather than crops is that we might not be able to feed ourselves if there are massive fluctuations in oil prices or disruptions in the supply of it.
But enough of the big picture what-ifs. How about the very tangible implications of highway spending, which as shown above, only alters the shape of cities, not the speed of them as intended. We would still have all of the same needs and wants, so we would go to all of the same places, just get there as a matter of choice in how we got there. Car-centric development just displaces those, ahem, places. It does not improve anything. It just costs. A LOT. To build, to maintain, and to use.
Below is the High-Five at 75 and 635. How many hundreds of millions did this cost? Also costly, the land it takes up...
At the same scale, you can nearly fit the entirety of the independent nation-state of Vatican City.
The downtown mix-master is another waste. And perhaps more importantly, all of the un- and under-developed land around it, because really, who wants to be near a freeway? Despite the '80s business/developer attitude to increase visibility along a freeway, people/business/workers would rather be on a nice street or plaza, near other people, places, and things. This can only happen in areas unencumbered by freeways.
While we're redeveloping all of this area with real, walkable urban neighborhoods, why don't we fix up the river too. If we're going to have walkable neighborhoods nearby, people might actually want to access the Trinity if they're not playing frogger across a freeway to get to it.
It is amazing how much wasted land sits on public property (the right-of-ways) as well as private property (along the highways). If we were really looking out for the best interest of citizens and property owners, we would tear out freeways to build up tax base via density, reduce tax burden on all citizens (less public land, less infrastructure per capita), and maximize the potential of privately-owned land that mistakenly thought being next to a highway was valuable.
D/FW is the fastest growing metropolitan area in the country. Where do we expect to put these people? At the edge, where they have to own a car? The country is also getting poorer if you haven't noticed, meaning we can't afford to build out there unless we're talking about self-sufficient homesteads that provide their own food, energy, and infrastructure (roads/waste treatment). Lastly, if we're already maxed out at our "1-hour wide" city, we can't get any bigger. The opportunity is literally right under our wheels and it is owned by all of us. We just have to demand the best use of it.
Or, we could just acknowledge the 40,000 deaths per year that occur on freeways, declare neighborhood adjacent intra-city freeways a public safety hazard, and condemn them. Wouldn't that be interesting, a City declaring eminent domain on state-owned property?