Well, presumably the bus is going to go its route whether you're on it or not.

If there's an increase in utilization of public transport, to the point where they need to run each route more often, or introduce additional routes, that'll be seen later on, when the impact of the ticket is evident. At that point, it can be weighed against any changes in private transport behavior.

It's probably premature to take upfront action against overutilization of public transport.

The enlightened big brain politically impossible is to internalize as much as possible. For example, everyone could have a device on their car that records how much carbon they emit and reports it to the government so they can be taxed. The amount they should be taxed is not trivial to determine, but an upper bound would be the cost of offsetting or capturing the same amount of carbon they emitted. (you don’t actually have to spend it on that, the point is just to incentivize people to avoid emitting carbon)

Then increase train fare so it’s at least as expensive per-carbon-emitted as driving. Since trains emit much less carbon, it will end up being cheaper to get from point A to point B by train.

Driving or taking the train has another cost, congestion. (more drivers means it takes everyone longer to get to where they’re going, more riders means some people might not be able to fit on the train. that second one used to be a common occurrence to me.)

Now that might seem hideously unfair to poor people. The solution is to take all the revenue collected this way and redistribute it throughout the jurisdiction where the law is enforced. The poorest would actually see an increase in their purchasing power. That’s because poor people emit less carbon on average, so if e.g. a poor person emits 1 ton per day and the average is 2 tons per day (making up numbers), they would pay the tax cost of emitting 1 ton but receive the tax cost of emitting two tons. The money would come from wealthy people who emit 3 tons but only receive the cost of emitting 2. That way everyone is incentivized to emit less without it unfairly burdening the poor.

The amount of carbon emitted by a car is directly proportional to the amount of fuel used, so what you really are talking about are fuel taxes which are very common already

That's the best way to make people switch back to cars imho. Not only does constantly paying a fee increase friction significantly, the same is not the case if you were to use a car you only need to refill every other week or so.

At the end of the day the total number of trips are probably not very elastic, because the price (if it isn't a very high one) usually isn't even a consideration if you want to go somewhere (if it's not that far away anyways).

Taking a trip on public transit to pick up groceries (or any similar task) still consumes time and is not convenient. I used to live in Manhattan, go to the shop on foot, and carry my groceries home. I would absolutely buy as much food as I could carry and use, because it was 45 minutes out of my night that could be used for something else, whether I bought 4 days of food or a single head of lettuce. People don't generally joyride public transit unless they have no other options.

In fact, having lived both ways, I'd say you're far more incentivized to do this in a suburban setting with a car, since you're sitting in a private bubble with your own music and climate for every part of the trip except the store itself.

> People don't generally joyride public transit unless they have no other options.

I think this really depends of the network you are talking about. In some European cities, public transit networks are a blast to use. If frequencies are high enough, and modalities are well connected, you can "ride" the city as easily and naturally on a metro/tram/bus as you would have done by walking. I've took a lot (a damn lot) of bus/trams just because they were there, passing by, and allowed me to save 3 or 4 minutes (with my annual ticket, price was never my mind).

(But I'm lucky enough to live in one of the lowest CO2 emitting countries in terms of energy mix.)

Fair, not every city has public transit as "gritty" as NYC.

I do remember an UberPool trip I took. We got another passenger along the way. The driver ended up having to go 8 blocks out of our trip's path to pick up the passenger. She went 1 block and then got out. At least when you take a bus or tram out of convenience you are not being so wasteful.

Nope, for most ppl the 1EUR is negligible anyway, and also people values its time, so, it's not free to go now, it costs time. the only thing you want to punish is to be poor, as in that plan, only poor people would have to minimize movement for economic reasons.

I think that your consideration is a good one, but I think it comes down to numbers. Will a no-additional-cost-per-ride pass increase the "unnecessary" load on the system so much that they need to start using additional transit vehicles, thus increasing emissions? What percentage of trips are "unnecessary"? Will the growth of the system for "necessary" trips be able to handle the "unnecessary" load anyway?

Aside: for "unnecessary" trips, I'm setting aside the possibility of other options, such as "I already own a car and will now use that instead of paying 1 EUR".

But the public transit lines would already be running, you are just hopping on a bus that is already going to be spewing some climate change gasses. Adding a car for a small trip would be detrimental because that car isn't already on the road spewing.

NOW you are correct though, better for all would be for people to walk to their local shops and stuff and only grab transit when they need to go beyond the 2-4 mile radius that is considered walkable, and that would pull some of the public transit off the road/rails.

> But the public transit lines would already be running, you are just hopping on a bus that is already going to be spewing some climate change gasses.

At least in Prague, they put more buses on the line, use larger buses, use streetcars with two cars, and they even build new underground lines (very expensive) in directions where the capacity of buses is not enough. So no, by hopping on a bus "that is already going", you are contributing to this.

Yes it would. But fees incurs overhead for managing tickets and is a hassle for passengers. A lot of European cities have good mass transit systems but people are lazy so they still drive which causes pollution and congestion. So the first priority must be to make mass transit as convenient as possible to motivate people to stop driving.

The marginal cost is basically zero per additional public transit user, no? If a city bus runs every 15 minutes, the ridership volume changes nothing up until some critical point is reached where another bus gets added to that route, or a new route is added.

Yes, from that point of view it would. Maybe not better from all points of view, but not travelling, or travelling by foot or bicycle is better than travelling by public transit, from CO2 point of view.