Time is a circle

Many cities paved over their tram lines. Sometimes they poke through during road work. We had trams in nearly every city 100 years ago yet today people tell me we can't afford it or our population is too small to support it. If we could do it 100 years ago we could certainly do it now.

I'd be very concerned about the state and safety of those rails.

Bus lanes are too easy for the next politician to remove bus priority and allow cars back into the lane. At least with rails it's a lot more costly to remove the route. Busses also still contribute to microplastics and tire waste compared to railed trams. Trams are also easier to automate which can make employing drivers and adding trams to lines less difficult compared to buses. The rails are also more effecient as there is less friction.

I'd defintely take BRT over no transit but many cities are dense enough to justify electrified trams.

Just lay rails in the lane. Turn it into, I dunno, a fuck you I'm a train lane

Going backwards while the rest of the world builds more functional and fair cities. We feel just as bad up here in Canada where our provincial premier is overstepping cities to force them to remove bike lanes that just got installed. The lanes are along a subway corridor and there are several apartment buildings planned on those roads that have extensive bicycle parking plans with much less car parking. And we've got big plans for new highways while we refuse to build rail along the densest part of our nation.

Within cities?

Look, aircraft are Hella noisy and if stuff goes bad, they'll smash into buildings. Using them for intra-urban transit is not safe. Besides, I don't know if multicopters can autorotate^[1], which only adds to the safety concerns.

So why not bring it slightly closer to the ground. Maybe put the transportation device on a bridge or viaduct. And while you could put some stairs up from the streets, you may even choose to link buildings into them directly. Most tall buildings have lifts, after all.

Next, giving each building its own link into the system would be excessive. You can achieve 90 percent of the utility if you have larger entry hubs for multiple buildings, and expect people to walk the last mile.

Anyway, back to the vehicle, since a vehicle for a handful of people is rather inefficient, why not build the vehicles for many dozens of people? Why not build it to connect multiple vehicles? If you run, like, four of these, every five minutes, most people will be able to walk up any time and just go.

And to make that movement more efficient, let's have our vehicles roll along a specifically designed path, optimised for minimal friction by using hard wheels on a hard surface.

There, I replaced the quadcopters with a train.

EDIT:
^[1]: According to one answered question on a StackExchange page, the answer to this question is probably no. Autorotation requires some magnitude of control of the pitch of your rotors, something that most multicopters do not have.

It does make me intrigued to see what'd happen if you could or did fit a multicopter with swashplates and pitch-adjustable rotors.

Everyone thinks the sky is big, without considering just how unscalable flying cars are

• no building is designed for large scale entry/exit at roof top. Most don’t support any
• the low altitude airspace over a densely populated area is very limited. Given current separation, minimum altitude, speed limitations, a city can support only a small number of flying cars. And no, “smart” vehicles don’t change the laws of physics, even if they help us get closer to them
• a flying car will always be more expensive than a not flying car, which will always be more expensive than transit

Let’s stop worrying about new ways for the ultra-rich to avoid the frustrations the rest of us have to deal with, we’ll all be better off if they also have an incentive to design more effective cities and transportation for everyone

And once we have one of those, mind as well build a mass driver at the top so rockets don’t have to carry so much of their own mass.

You wouldn't even need a mass driver. You have to build your space elevator so that it's center of mass is where you want it to orbit. Logically, this needs to be at geostationary orbit so that the end point on the ground stays in the same spot. That means you can extend the other end of the elevator to twice geostationary orbit. Lift a mass from the ground to the far end of the elevator and just let it go. It will be flung away out of earth orbit because it'll already be moving faster that orbital velocity at that height. You're limited in the direction you can fling it because it will be flung off by the Earth's rotation, but you don't necessarily need a mass driver.

I mean, currently both space elevators and wormholes (as transportation) seem physically impossible.

If we're not sticking to the realm of our current understanding of physics, then that opens the doors for techbros too, because we're in the realm of speculative fiction and things can be however we say they are.

Trains are extremely convenient. You optimize them for convenience by adding more trains.

And yet a coordinated approach with multiple strategies will most effectively cover every use case.

• conservatives get too attached to personal vehicles as the strategy they are most familiar with, most focussed on
• too many transit advocates recognize the limitations of personal vehicles and the advantages of rail, but tend to speak in absolutes that scare conservatives.

Yes it’s critical that we refocus much of our transportation effort to give more people better choices in more scenarios, but that will never rule out cars

It would require a Manhattan Project sized effort, but I think it could be done

I mean...I don't want to live in it, I just want it to be able to handle both roads and rails and zip me around

You'd think so. But at least Germany struggles massively with missing personnel to staff trains (which includes roles beyond the driver). As far as I know there is no automated solution on the horizon for any form or scale of train traffic. The only self driving trains I have experienced require tight control of the rail environment (entirely underground or lifted above the surface) and special stations with airlocks.

Maybe there is just more money in self-driving cars. But I'm pretty sure they will happen before wide spread automated trains. Which sucks.

That's not most trains. Those are highly specialized and constrained applications. There are already self-driving taxis in certain defined city areas, so they're still ahead by that standard.

if time is no line then the universe has no structure

Yeah, but the roadways are here now. And this discussion is moot anyway. Trains aren't happening. Self driving cars are maybe happening.

That was my point.

Dense cities are just one of the many environments people live and travel in, and mass transit or metro is only one mode of transportation we need.