>But what do you mean by "ending the rules that force a suburban character".

In most of America, there are a number of zoning regulations in most suburbs that make building anything other than a single family home on a large lot illegal. Likewise the suburban strip mall or giant sprawling Walmart isn't just what people may or may not want, it's what the law requires.

Let me use an example that I know of personally: Culpeper, Virginia. Culpeper is a small rural town that developed along the historic railroads as a place for farmers to bring their goods from the surrounding farmland, load them onto trains, and maybe get some goods while they're in town. It still has within the (expanded) town limits farming equipment dealers and a place to drop off crops to be shipped off. The downtown is historic, dating back to the late 1700s with buildings from that era and the 1800s still around. Here's a representative street view: https://goo.gl/maps/jJUUg2JZzEk

As you can see, this place has a number of stores, some with housing on top, and nearby housing. This is what's known as 'mixed-use' development: instead of being purely residential or purely commercial, the two are both allowed to exist in the same space (or even the same building). The town is laid out on a grid, which disperses traffic and makes walking efficient. There is no parking other than street parking and a small parking lot or two the town has provided.

Contrast this with the current zoning rules. In most of the town, the smallest allowed lot is something like 15,000 square feet, which is about a quarter acre. As you can see from the street view link, none of these buildings are on a lot that size. None of them would be allowed under this rule alone.

OK, so maybe the buildings would be much bigger under current rules, but that could still result in a dense urban environment. Unfortunately, the town has added additional rules that require side yards (100 feet minimum, IIRC) and a large setback from the street. This means none of the buildings would be allowed to touch, meaning the historic walkable downtown core would be illegal under either of these rules.

OK, you protest, maybe we could still have a walkable town that's dense even with both sets of rules. We could build taller to make up the density, though it would be more expensive.

To prevent this, the town limits what's known as the floor area ratio, which is the square footage of the building (across all floors) divided by the square footage of the lot. So a FAR of 0.5 would mean that the total square footage of a building across all floors would have to be at most half that of the lot. This is the exact limit the town has imposed in most circumstances.

This means at least half of the minimum quarter acre lot would be empty, and the largest unit possible on the smallest allowed lot would be about 7,500 square feet (using the standard minimum of 15,000 square feet), without taking into account setbacks and front, back, and side yard requirements, which would further restrict the allowed size, especially on a more narrow parcel of land. A 7,500 square foot house is huge, so you won't see too many of them.

The town does provide an option to build townhouses and apartments more densely, but it's roughly 5 units per acre for townhouses or 8 units per acre for apartments if I'm reading the statutes correctly.

For all uses, only 30% of the lot may be covered.

Dense development is now out. But we could still build apartments next to grocery stores and shops, right? That would still allow people to walk to something, even if it's not particularly dense. Nope.

Except for downtown, and then only for certain town council blessed kinds of businesses (like barbershops), mixed uses are illegal. Your residential area must not contain commercial. Your commercial area must not contain residential. No apartments over stores allowed, sorry historic downtown. Hope none of your buildings burn down, because it would not be legal to rebuild them.

OK, so we can't mix uses, we can't build densely, but we still don't have to build strip malls, right? Wrong.

Culpeper, just like many areas, has a dizzying array of parking minimums that require X number of spaces provided per unit or per square footage in commercial properties. It's randomly generated and not based on any market realities, just like in most areas. In many areas they also mandate that the parking be free.

What this means is that a huge portion of land must be used for parking or businesses must provide parking garages. Both are hugely expensive; even in a rural town like Culpeper land costs tens of thousands per acre. Underground parking can cost $10,000 per space in construction costs. A large surface parking lot just in land in a place like Culpeper can cost $100,000 or more, and then you have to add on paving and maintenance. Who knows how much the environmental cost is?

This isn't just some podunk town regulation; even New York City requires this outside of Manhattan in a lot of cases, even if exactly 0 people want the garages. Their land is expensive enough that typically parking garages are the preferred option and they might actually allow charging for parking. Too bad many garages will sit mostly empty. It makes it difficult to build on a small scale since the parking garage will eat up a huge amount of money and require entrances, reducing the developable land.

Given the interaction between all of the various statutes, the strip mall and suburban Walmart style store is all that's allowed to be built in most of America.

Even the places that get it mostly right, such as Arlington, Virginia (to use another familiar place) still have parking minimums and still force suburban living outside a narrow corridor. Right next to Metro stations Arlington has single family housing when there's an affordability crisis and declining Metro ridership. I can think of a way to fix that.

There's also an office space crisis in Arlington; too much was built, not enough was rented out. Without single use zoning, the office buildings could be converted to residential and rented out quickly. Single use zoning forces them to sit vacant. If the opposite situation occurred, apartments would sit vacant while office workers are stacked on top of each other to make use of expensive real estate.

There are other ways in which cities and towns promote sprawl. For starters, when developers build new subdivisions, they have the developers build roads. These roads tend to be cul-de-sac style roads because they are cheaper to build; less road surface is needed. They also are hell for traffic, reduce emergency response times, and make walking difficult.

Rather than rejecting these designs as more costly and bad, the cities and towns gladly take over maintenance, knowing they'll have to widen every road a thousand times in a never ending circle of congestion. Virginia is actually trying to force a certain level of connectivity to prevent this, but the rules are not much better than what currently exist; the cul de sac can live on, just with a few more internal connections.

Roads are heavily subsidized. The gas tax mostly covers highways and interstates (and even then does not actually cover them), so local roads are paid for mostly with local tax dollars. Non-drivers pay directly in local taxes. Drivers pay nothing for congestion costs even if they do actually cover the cost of building and maintaining roads. Free roads make transit, which used to be mostly profitable private businesses, unable to compete and thus require massive subsidies.

Federally, transit is screwed from a regulatory standpoint. Transit systems are forced to provide paratransit services that can charge at most only twice the most expensive fare between the two points. The idea was to force systems to become more ADA compliant to cut costs, but the regulation actually forces a 100% ADA compliant system to shuttle around people within a half mile of station to a destination within a half mile of station.

Part of the problem is that the regulation specifies that you must provide service to people who can't get to your system because local streets are not ADA compliant. So if your city never upgrades its streets, you as the transit system must pay for their failure. You can't rip them up yourself, so you're financially screwed. Congress could and should have put this mandate on cities, making them more likely to upgrade the streets.

These trips are super costly: some agencies spend a third of their operating budget on these services. They've started contracting out to taxis to handle the work, and taxis aren't cheap (though are cheaper than paratransit vans). The user might pay $5 for a $20 cab ride. This forces transit to either raise fares and be less competitive or get a higher tax subsidy. Solo drivers face no such mandate.

Somewhat related, intercity trains in the US basically can't use European or Japanese trains due to outdated 1920s rail regulations without all kinds of special waivers. This makes rail travel slower and more expensive than it would otherwise be.

TL;DR lots of laws need to change