The problem here isn't the cities, so much as it's people living in the scrubland hills and forests who insist (understandably) that CalFire put out each and every fire before it destroys their property. The problem is that California's environment evolved around cyclical fires burning out undergrowth, and when that isn't allowed to happen, the result is detritus build-up, leading to these mega fires that destroy everything. Mega-cities are better for the environment, ultimately, than scattered villages and homesteads.
This is true of some regions of British Columbia, as well, particularly around Kelowna. People want their hillside homes and ranches, and when the forest fires happen (every year), it always seems shocking to them that fires don't give a damn what they burn.
The solution is to get more people into cities, and stop the sprawl. Not to sprawl more. Let more of the wild remain wild. For those who choose to live and build in wildfire prone areas, require them to build of flameproof materials, or have no insurance and no government assistance to rebuild.
I've just finished voting for the municipal election (in-home ballot). I had a look at the candidates last night, and opted not to vote for anyone whining that there's too much development in the south part of the city and not enough in the north part.
I do live in the north part and it's true that we don't have all the malls and recreation facilities the south has. But the city is surrounded by wetlands and whatever farmland hasn't already been gobbled up for new subdivisions, industrial, or oil and gas. I remember when a significant portion of the south half of this city was farmland. The acreage I grew up on was eventually annexed and is now paved over. So much for the deer and migratory birds we could count on seeing.
As much as I loathe the idea of having skyscrapers here (the number of skyscrapers we have in this city can be counted on one hand, and two of them are apartment buildings that are maybe a third the height of a Calgary skyscraper), we need to preserve those wetland areas.
Why do you need to widen the freeways and major roads in the cities to increase urban populations. In London 37% journeys are made on public transport, 24% by walking and 2% by cycle with only 36% by car.
http://content.tfl.gov.uk/travel-in-london-report-9.pdf
Far too many North American cities - large ones in particular - don't believe in public transit.
Around here, public transit is seen as something only students and poor people use, and I remember one municipal election forum some decades ago, in which a member of the audience asked for a show of hands among the council candidates as to which of them had ever used public transit.
About a third of them raised their hands, and one of them looked around furtively, raising her hand no higher than her shoulder. Her attitude just screamed, "God, I hope nobody who matters saw that I took the bus once!". Or it could be that she wanted to appear to have taken the bus but didn't want to be the only one who raised her hand. Considering that she lives in one of the swankiest parts of town, I very much doubt that she took the bus more than once, if she ever took it at all (she was elected to council and 3 years later was elected mayor and never did understand the importance of public transit and timely snow removal in the less-swanky neighborhoods).
"Bicycle lanes" is a four-letter word here. Considering that they're covered in snow for at least 6 months of the year, drivers aren't too happy with them. We do have bike/walking trails throughout the city, but these don't go into the middle of downtown, and I'm not sure how many of the newest subdivisions are connected yet.