There are people out there who believe that. Many of them are in the planning community, busy designing all kinds of connecting trails to let people walk to public transportation, when they get around to trying to ban cars...
I have always maintained that the hoopla surrounding SUVs and 4x4 vehicles has very little to do with gas guzzling and a lot more to do with being anti-gun and anti-hunter. To a moderate degree anti camping. Think of the plan ALGORE first posited in his original book way back from the 70's (forget the title but it played a role in the 2000 election) where he advocated banning the internal combustion engine and a forced movement of populations to coastal cities so that the interior of the nation could be returned to pristine wilderness. I kid you not. Now bear with me and think about this 'cause it could lead into the fringes of areas lined with some ummmm tin foil.
The ELF terrorists blow up Hummer Dealerships allegedly because of their anti-green resource guzzling elements. Many legislators are upping the mpg requirements way beyond what is possible for 4x4s to actually go off road. Without 4x4 capability two things can be accomplished.
First: A lot of hunters will be unable to reach hunting grounds safely in inclement weather or in rural areas where terrain is more extreme than usual. It will also severely impact folks who own hunting camps for a living as well as professional guides (a small percentage perhaps, but we're still talking livelihoods) and all the ancillary industries that support recreational hunting. THAT is a huge statistic, not that the communists & globalists that are pushing such plans even care. If there is no way to get to the hunting area and no way to haul the game home then there is no more need for "sporting use" firearms. Suddenly that bolt action scoped rifle is a true sniper rifle and must be banned. The shotguns will be wmd's and banned. Handguns suitable for hunting will go just as easy and small handguns for self defense will then be even easier. Especially in that political climate.
Second: Consider the need for a government in an emergency or perhaps catastrophic situation to control movement. How is this accomplished? Over the short term, like 911 you can simply ground everybody. No vehicles on the roads except military or police. Martial law. In the long term, folks have to drive. Work, school, grocery, etc. How then will a government entity control the movement of a population for a long period of time? Roadblocks. Checkpoints. Think USSR old school. A lot of folks will wonder about the ability of any government to regulate the GO-zillion miles of secondary roads and the obvious answer to many will be "no." But that's for personnel. But if you wanted to prevent passenger vehicles from traveling between cities or townships (in rural areas) then it's a pretty small matter of cratering these roads in such a manner as to create permanent obstacles to passenger cars. It can be done with civilian road equipment or a small application of explosives. That might take some time but it's doable over the long haul.
The publics options in getting around such restrictions? Horseback. Motorcycles (requires skill beyond most folks abilities) and .... you guessed it .... 4x4 vehicles. With very little training (certainly a part of every truck owners normal abilities if he uses his 4x4 for real) anybody can take something like H2, H3, Range Rover, or Ford Explorer (you can name any vehicle you wish, but you get the idea) anywhere cross country and roads really aren't all that necessary. They would certainly make easy detours around blocked secondary roads. In such freedoms lay the roots of an insurgency.
Americans are sheep, mostly. Sure there are sheepdogs but we are vastly outnumbered by the wolves. If you don't understand these references there is an essay you MUST read: "People: Sheep, wolves and sheepdogs" and you will truly be enlightened.
Understanding the sheep nature of the vast majority of Americans (the fault lies in the propaganda of the educational system) and that the likes of the WWII generation are forever gone then you can see how easy it could be to establish total control over the nation. We've been prepped to accept exactly these circumstances for a century and actively so since the 1960's. Via education, legislation and the Democratic Party's nanny state.
The agenda has been very careful to be advanced in tiny increments. The groundwork was accomplished over generations via education and media. The pressure was ramped up over the threats presented by a variety of crisis situations, like the cold war. That was something with global implications that affected the whole world. When that went away (mostly but now resurgent) the great majority of communists and their masters in the globalist movement were lost and found shelter with the other nutcakes in the extremist environmental groups. These have always been funded by communist groups but now get a lot of funding from NGOs in the United Nations and groups funded by George Soros and Ted Turner etc. A lot of the Hollywood set give mega bucks to these groups all the time. I don't even know if they're aware of the real agenda for the long term. Maybe.
The environmental movement provides a whole plethora of "causes" to save the planet. That is what the agenda requires. An imminent danger to the whole planet caused by man's stupidity that can be changed IF man is willing to change. By this it means major, sweeping and immediate societal changes.
This is what folks like Dianne Feinstein are talking about (Hillary and Obama, too) when they mutter to the media that we're all going to have to surrender some minor constitutional liberties. Look at the European Union and take a gander at the proposed North American Union (a work literally in progress) and glimpse our near term future. Because believe you me, it all ties in together. As it continues to progress, more and more folks will either be shutting up about tin foil people or buying a supply of their own.