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Comment by nimos | Hacker News Reader

I wish they would make self attaching electric/battery trolley busses. The main lines on the streets in Vancouver aren't bad but the intersections are such a mess with the trolley lines. You could min-max a system that combined trolley lines with batteries and use much less of both. Put the starts above bus stops so they don't have to attach at speed and you get to cover the initial expensive acceleration too. Back of the envelop guess from supercharger times is you would only need 10-20% of the routes actually covered in lines to maintain battery charge.

It'd also be nice if more of the self driving companies would go after busses first. Fixed routes seems like a significantly easier problem and you can amortise all your sensor/electronic cost over a more expensive vehicle.

Both combined would pretty radically alter the environmental and economic cost of public transportation.

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Partially or fully caternary-free trams that utilise supercapacitors are already deployed in some cities like Guangzhou, China and Zaragoza, Spain. It is probably not too much of a stretch to extend this concept to trolleybuses. Like the trams, they can use charge points at stops either overhead or embedded in the roadway.

You just reminded me how much I hated the trolleys when I grew up in Vancouver.

I don't want them to come back. One of the key advantages of buses is that they're flexible and could react to shock loads. Moving people in bulk should be done with grade-independent rail, like the Skytrain.

I wasn't a huge fan of them growing up in Seattle either, but the new ones are so much better. They have lithium batteries, a few miles of off-wire range, and auto-detach/reattach for the poles. Basically solved all the problems.

They're also much peppier, and have AC.

They are planning to do something similar in Tempe, AZ I believe. From what I understand, it's going to disconnect when it turns onto Mill Ave (which is the big bar/restaurant/shop street) and then reconnect afterwards.

PDF Link to Map: https://www.valleymetro.org/sites/default/files/uploads/even...

The self driving companies won't go after buses first because they haven't already gone after buses first. Google's been using the mid-large size vehicle for years now. It is much smaller, more manueverable, better acceleration, lower costs to procure, and yet another benefit is you're not limiting yourself to wherever the buses happen to have to go. Buses have to stop/start on the whims of the driver, so is Google going to make a self-driving bus but still have a driver there to make it start/stop? Where is the efficiency gain? Where is the helping of the handicapped or uncapable that they achieve with personal vehicles? I think all the companies in the space have it right, personal vehicles first, as well as freight vehicles, and then trains/planes/buses later since they already have skilled drivers that we'll have to retain anyway.

> Buses have to stop/start on the whims of the driver, so is Google going to make a self-driving bus but still have a driver there to make it start/stop?

Buses have to start/stop based on passengers desiring to exit, passengers waiting, and passengers completing loading. Drivers detect and react to those conditions, but it's not about whim.

They have done this in Seattle for the first hill streetcar [1], with let's say limited success [2][3]

[1] https://en.wikipedia.org/wiki/First_Hill_Streetcar#Vehicles [2] https://www.king5.com/article/news/local/sdot-pulls-first-hi... [3]https://www.seattletimes.com/seattle-news/transportation/sea...

There are trams that do things similar to that, for instance some Alstom trams switch between APS and catenary at some stops.

For buses, you might be interested in this: https://www.oppcharge.org/

Trolley buses are kind of on the way out with battery operated buses. I doubt they would use the trolley lines for supercharging, that would require way too much infrastructure when the super chargers could easily be centralized at a few stops.

Would battery swapping require less infrastructure investment and be much easier to deploy?

I guess detailed calculation using future projection is necessary to make a case for either one. The choice would also depend on local circumstances.

These already exist in Europe, primarily used for construction works, but they might become used for certain sections of some new bus lines doon.

Are trolleys more efficient than buses, pound for pound? Especially after you factor in the capital expenditure needed to build out the trolley lines? I find it hard to believe that a niche technology (trolleys) would be more efficient overall (impact * quantity) than buses, which are everywhere.

Buses are probably an 'easier' problem, but it's much easier to pitch selling self-driving cars to individual consumers rather than to government procurement budgets. Also, I suspect the bus problem space introduces additional issues such as <what to do when some asshole is parked in the bus bay>.

You seem to be thinking of trams, while nimos is talking about trolleybuses, which are buses that draw their power from overhead wires [0]. Specifically they're suggesting that a hybrid option with batteries would reduce the need for wires everywhere (just run on battery power), but would still allow the buses to charge while connected to the overhead wire.

[0] https://en.wikipedia.org/wiki/Trolleybus

But the trolleys are already in place in many places around the world...?

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