Even if you think what you would say is obvious, please add. This is genuinely something I think makes sense regarding local bus routes given the longevity of light rail and how infrequently routes change, but I also suffer from confirmation bias, so I’m hoping for reasons this would be a terrible idea but obviously would prefer reasons it would be an even more amazing idea than I thought.
Light rail/trams are better especially for avenues etc. But busses are more flexible, and you usually need a combination of both for best results
This.
I think of buses as the caterpillar to a tram’s butterfly.
You can start with a comprehensive bus network, and as a particular route stabilizes and the bus starts struggling to meet throughput needs, that is an indicator that a tram may be worthwhile.
Starting w/ a tram line is a pretty big financial bet that it will be useful/needed, as once you build it, you’re locked-in to that specific route.
Buses for longer journeys make sense. We have a bunch of buses in London that run from the city centre out towards the green belt. Buses for those especially long journeys makes sense.
Why not just build a train for long journies? Cheaper over time, more capacity, and reduces road dependency.
I’m surprised nobody pointed out that tyres are extremely polluting:
https://www.theguardian.com/environment/2022/jun/03/car-tyres-produce-more-particle-pollution-than-exhausts-tests-showBusses have their uses. Lots of commentor have mentioned the flexibility in setting up / changing routes. But there’s also the flexibility in sizes. You can start a line with a large van or small mini bus and your only overhead is the driver. From there you can scale that up according to demand up to frequently run articulated busses. Meanwhile your minimum investment for tram includes at the very least a not inexpensive track installation.
Don’t get me wrong. If you have the passenger volume that investment definitely pays off. But I don’t like this unnecessary competition between two modes of transport that can be very complimentary to each other and are both better than individual cars.
Light rail is infinitely more expensive to construct and it only takes one delay/accident and all subsequent trains after cause a log jam…vs a bus which can route around it.
A better solution uses corridors dedicated to buses that are electric powered.
Something like this was done in Colombia with these routes being connected by ground hubs, similar to subway stations.
Here in NYC, we switched to hybrid electric buses many years ago and are currently transitioning to all electric buses. I’m not sure about other cities. 
That’s like saying a ship is more expensive than a car. It depends.
A tram is not „infinitely“ (what absurd statement is that anyway) more expensive than a bus.
Construction cost is not everything, and they’re not even that much higher, you also need to consider service life (much longer with trains), energy cost per passenger mile (much lower with trains thanks to the lower resistance), etc.
What is best is always depending on the specific circumstances.
The biggest limitation of buses is capacity, and a highly used tram is cheaper per passenger mile than a bus. Try replacing the S-Bahn in Berlin with BRT, see how far that gets you. You’d probably need to bulldoze a new highway… speaking of which:
Germany is actually hellbent on building a highway right through its capital Berlin, which currently clocks in at 700 milion € for 3.2 km. I expect the whole thing to end at ~2 bn € for ~7 km.
So I think the costs of public transport are really not the issue people should be focusing on.
This is a common misbelief. Trams and light rail usually have points where the units can go around if one unit has derailed, unless the unit has tipped over, which in itself is very very rare. Good planning is crucial. “A better solution uses corridors dedicated to buses that are electric powered.” Nope, nope, nope. You have to present arguments to this claim, maybe then I can be bothered to counterargument such nonsense.
Depends on the road layout; if it’s a long straight road then light railway makes sense. It’s less maintenance, easier to operate, can move unhindered because it doesn’t get stuck in traffic (edit: provided they don’t share the roads).
For spaghetti road layouts though, I don’t see the benefit, but I could be wrong since I’m no expert.
There is no reason rail has to be constrained to the road network. Eminent Domain is literally for things like this.
We tried in Denmark (Aarhus). Quite expensive, and too many issues. Electrical busses (with dedicated lanes) seems like the better solution,
busbut this is also not cheap.Edit: Spelling
What about hydrogen buses?
My guess is that hydrogen busses suffer the same challenges as hydrogen short-distance trucks. Due to an overall low energy efficiency (electrolysis -> compression -> decompression), it makes better sense for long-distance transport.
