[cucho]

That's actually the standard model for evaluating transport projects: aggregating small time savings across millions of people.

You basically take those millions of saved hours and multiply them by a government-standard 'value of time' (roughly £15/hr in the UK). That usually makes up the bulk of the benefits, though they also price in things like safety (a prevented death is worth ~£2m), carbon, noise, etc.

IIRC, if you hit a Benefit-Cost Ratio of 2.0 or higher, the project is considered 'high value' and has a good shot at getting executed.

[lanthade]

This reminds me of a story I heard about a bus driver who would always pull away from the stop right on schedule even if a regular rider was running up. His calculation was the 30 seconds spent waiting for one rider was an aggregate of many minutes lost by the riders who were on time for their stops. What looked cruel to one was a kindness to many.

[integralid]

>many minutes

A bus can easily carry 50 passengers. 30 seconds times that many is 25 minutes. That's a lot of aggregate time wasted indeed.

Also assuming this 30 seconds delay is not compensated later, it can influence significantly more people than the bus capacity. And if someone misses a connection because of it that's even more time wasted.

[ramesh31]

Training on conversations like these are why the Skynet LLM will optimize us out of existence within moments of coming online.

[buckle8017]

The value of saving a human life is a huge factor in civil engineering and varies pretty widely in the western world.

IIRC it's over 10m USD in the us currently, but only about 6m USD in most of the EU.

[integralid]

It doesn't make sense to compare such numbers without PPP adjusting thought.

[brcmthrowaway]

What companies do this CBA? Deloitte?

[cucho]

Economic BCAs are typically handled by large eng firms like Arup, Jacobs, and WSP. However, the tricky task of modeling time savings (given that transport systems are complex) is often subcontracted to more specialized firms such as Steer.

Deloitte, KPMG, etc are usually more involved in writing the financial case (how to fund the project).