Think about another example of a public project as follow that uses a certain input for which there is no market and post as a paragraph.

(For instance, if the project consists of setting up a new provincial or national park, one of the cost categories involve hiring both paid personnel and volunteers, to staff the many aspects of running it in the open season. Depending on the remoteness of the park, the compensation scheme for all employees may include a daily or monthly amount for mileage, which is typically a fixed amount that is independent of the actual distance traveled to work by each person. Obviously, there isn't a market for traveling to work as an input, so a shadow value needs to be calculated. A more precise estimate of the true social cost of the human resources needed would beto tailor the travel reimbursement to the employee's actual travel cost, as a proxy for both costs with fuel or public transportation and their opportunity cost of time spent travelling.)