Talk about the UK rail network.
It is about CO2, one of the absolute last things relevant for a bridge. But of course there is a monetary reason for this person to do that:
Cross is also programme manager on Network Rail’s Flow Bridge project. Flow stands for fibre reinforced polymer
We need decarbonisation across all sectors so minimising lifetime CO2 of infrastructure - even public transport infrastructure is absolutely a priority.
Things like bridges have other priorities. They should last 100 years or so, the CO2 footprint is simply irrelevant. The relevant parameters are safety, longevity and a reasonable price. Stop paying attention to green washing nonsense. Focus on the important parts.
I think you misunderstand what a whole life CO2 assessment is. It factors in the carbon per longetivity. Often you will also be assessing other factors like cost per co2 too.
Rail is a predominantly upfront CO2 cost in infrastructrue for much lower operational CO2 costs and as such these questions are quite important if your job is decarbonisation of Rail.
This is pure green washing, the guy wants to make money with his "alternative" product.
Obviously transportation as a whole emits a lot of CO2. But not so much the infrastructure, since that lasts a long time, so even high initial emissions are quickly irrelevant compared to the emissions of using the infrastructure. Rails, being electric a lot and with low friction, are the best case(?) scenario "against" this. I would still assume that due to the decades of use that the initial upfront CO2 of making railways is somewhat irrelevant.