[leobg]

? It’s not like the machine would be custom built for him.

Are you saying it’s fine to drive a huge truck if you’re single and just need to get around the block to buy a pack of eggs, just because the emissions are nothing compared to those required for making that smaller, more efficient car that you could buy instead?

[onionisafruit]

If your only use for a vehicle is a weekly or even daily trip around the block to buy a pack of eggs, the best environmental choice is to use a vehicle that is already manufactured. If the only vehicle available to you is a semi truck, that’s the best choice. Even over a lifetime of daily trips, the difference in emissions between the semi truck and a golf cart won’t make up for the emissions of manufacturing the golf cart and transporting it to you.

Of course this is a contrived example that ignores the used vehicle market or the possibility of walking around the block.

[Groxx]

no, they're saying the emissions needed to create that smaller, more efficient car may vastly exceed their car's emissions during its entire lifetime under their use. so it may be a net loss.

[ahtihn]

The break-even point for the small car vs truck is much lower, so there it makes a lot more sense to switch.

[alehlopeh]

It’s actually fine to do that because people are allowed to make their own choices no matter how much you disagree with them.