Demand-responsive transport (DRT) has been tried a bunch of times in all sorts of different environments and pretty much never lives up to the promise. Predictability is really important and ridership drops as soon as users start having to plan too far ahead, which in the past has been essential to DRT routing.

Autonomy could improve responsiveness to demand but you still run into other issues. DRT usually won't be able to take advantage of things proven to make buses faster and more consistent (bus lanes, reducing stop count, transit priority signals). Futher, consistency and response times gained by dynamic routing can easily be overshadowed by increased variability in trip time as the route adjusts to add new passengers or make out of the way drop-offs.

> has been tried a bunch of times in all sorts of different environments

Has it? When, where and with what technology?

> Predictability is really important and ridership drops as soon as users start having to plan too far ahead

Uber etc have proven this to be patently false. Existing buses are experiencing dropping ridership - Uber is not.

> won't be able to take advantage of things proven to make buses faster and more consistent

You're replacing buses with auto-shuttles. Just let the shuttles use the bus lanes.

> bus lanes, reducing stop count, transit priority signals

All of these are usable if you widen the scope to include auto-shuttles.

> consistency and response times gained by dynamic routing can easily be overshadowed by increased variability

What is the difference between Busing and Shuttles here? A bus user can keep yanking the stop cord, there can be 1 or 2 disabled passengers who take several minutes to board, there can be 50 children getting on / off. These issues are constants and all are improved with demand based shuttles.

I've seen it work pretty well in a number of places in the form of privately owned minibuses/vans that can rapidly go where the demand is needed.

As an example, all throughout the Eastern Caribbean this system works really well (in my experience better than most centrally planned bus systems in large cities). On any given island you can go to any main road and within a few minutes a minibus will come along. Most of the time if your aren't familiar with the geography, you just tell the conductor where you are trying to get to, and they will make sure that you get off in the right spot to get where you are going or connect to another minibus. Typical cost was ~$2.

Predictability was pretty low, but because of the small size of busses, there were a lot of them roaming around, I don't think I ever waited more than 15 minutes, and that was in very out of the way places.

It's really not ideal. Similar systems are common in Central Asia. They make it difficult for travelers to predict journey times, it's unfriendly to tourists, and it's much less accessible to other populations (e.g. the disabled). They also don't scale well to large urban environments or out of the way journeys in my experience.

Yes, like all systems, it has tradeoffs. Although I would argue that some of the downsides you highlight are worse with traditional bus systems (e.g. the Caribbean bus conductors will happily guide tourists, and I have seen them go off-route frequently to drop off someone with limited mobility. Large cities in other parts of the world have managed to scale the system out to fill in gaps with other forms of transit like Lima, Peru)

The GP was arguing that it NEVER works out, and I'm just pointing out that it does work in many places.

I would much rather rely on the Caribbean minibus systems than try to rely on transit in cities like Phoenix.

> They make it difficult for travelers to predict journey times

How do scheduled bus routes standardize a journey time vs a demand shuttle?

> out of the way journeys in my experience.

How do buses fair in this regard?

> It's really not ideal

Are buses?

To standardize a journey time in a scheduled system, you subtract the origin scheduled arrival from the destination scheduled arrival. Map apps will even do this for you automatically. If the bus is unreliable, you add error margin. A demand shuttle system usually has a much larger variance, which means you can't predict that the journey time will be acceptable and you'll find some other way to get around.

    How do buses fair in this regard?

You look at the route map and the schedule to decide? Again, map apps make this trivial for regularly scheduled services.

I believe this is also how it works in many Mexican cities.

Those busses still need designated spots to stop at. They can't be stopping in the middle of a street

Indeed. And if you want a lot of people to board the bus efficiently at the same time, you need them to agree to congregate somewhere before the bus arrives. One might call such a meeting point a “bus stop” :)

> you need them to agree

The app would say - meet here.

> One might call such a meeting point a “bus stop” :)

Call it what you want, it could be in a strip mall parking lot, a convenient corner or just in front of the apartment building. Optimized for traveling distance between the passengers.

What’s the point of making this dynamic? Go find a city where people are out, having fun, and not buried in their phones, and where the city isn’t full of strip malls and parking lots. There will be people who want to be picked up during busy hours, and having a shelter from the sun or rain is nice, and having a place where there isn’t a parked car or an uber in the way is nice. Lots of Asian capitals are like this.

> people are out, having fun, and not buried in their phones and where the city isn’t full of strip malls and parking lots.

Are we still talking about how to optimize public transportation on city streets?

I think a bus could stop in the middle of the street, but a bus stop still removes dependence on a smartphone and protects from the weather.

No it couldn't, for legal liability reasons, usability for the travellers, etc...

Taxis/Ubers/... can and do stop in the middle of a street. Why would that be different for a bus picking up a single person?

yes, and it keeps blocking my bus. Fortunately it is now legal in Chicago for drivers to get fined for stopping in bus stops/bus lanes automatically via cameras on the buses. Not sure if it is actually happening though..

What if it's 5 people? 10? What if instead of many huge buses like today it's 5x as many smaller buses?

You can't just have buses stopping randomly everywhere, it doesn't scale.

The assumption is that a "waymo bus" would be hailed by an app and the service would plan routes on demand. In such case, bus stops would be needed only in busy areas or in places where it would be dangerous to stop.

This is based on the observation that people, including police, tolerate taxi drivers stopping at places where it's technically illegal.

funnily enough, they get designated spots and they still just stop in the middle of the street

If you keep asking self driving bros questions you can get them to eventually reinvent buses and trains. It’s fun!

Autonomy isn’t necessary, but aside from cost there’s nothing stopping a city from operating a bus more like a shared Uber ride. Having fixed stops at fixed times is fairly primitive. They would be smaller shuttles.

Autonomy is necessary to get the unionized bus drivers out of the way, the cost of running a bus is dominated by staffing costs.

Waymo is worth nothing if there’s congestion. That’s the problem public transportation solves, not lack of connectivity

Wait until you're waiting in the wind and snow with a toddler, and you'll prefer a bus shelter.