Serious injuries are some fraction of that, e.g., ~$1M for a limb. The correct tradeoff between safety and cost obviously depends on the marginal cost to increase safety, which is known to the project leaders but not us, but I'd be surprised if the optimal number wasn't between 5% and 25% of total cost. 5% of $500M is $25M, so for a project of this size I'd expect, as a lower bound, at least one death and a dozen serious injuries.
To be clear: by not making this trade off and by spending huge amounts of money to ensure such tiny injury rates, we are wasting resources that could be spent on saving lives at the rate of $10M/life. Indeed, this number is the key threshold by which the EPA decides which environmental interventions to fund, or the NHTSA decides which traffic safety measure to take.
https://en.wikipedia.org/wiki/Value_of_life
Serious injuries are some fraction of that, e.g., ~$1M for a limb. The correct tradeoff between safety and cost obviously depends on the marginal cost to increase safety, which is known to the project leaders but not us, but I'd be surprised if the optimal number wasn't between 5% and 25% of total cost. 5% of $500M is $25M, so for a project of this size I'd expect, as a lower bound, at least one death and a dozen serious injuries.
To be clear: by not making this trade off and by spending huge amounts of money to ensure such tiny injury rates, we are wasting resources that could be spent on saving lives at the rate of $10M/life. Indeed, this number is the key threshold by which the EPA decides which environmental interventions to fund, or the NHTSA decides which traffic safety measure to take.