Talk:Public goods

Definitions and sources

THe marginal cost of usage of a bridge or road is not zero. I am not particularly happy with this definition: will get back to you on this. --Martin Baldwin-Edwards 12:01, 11 November 2007 (CST)

You're right, there is wear and tear on the bridge. I guess what I'm trying to get at is that once you've already built the bridge, the marginal cost of making the bridge available to additional people is zero, not the cost of additional people using it. Making the bridge available for one person costs the same as making it available for everyone; maintenance is a different story. How about:

While a pure public good is strictly non-rivalrous and non-excludable, the more general usage of the term is that public goods should conform to both properties to a reasonable extent. Strictly speaking, a bridge is a marketable public good or club good because the bridge owner can build a toll booth and exclude people from using it. Furthermore, bridges are only non-rivalrous during slow periods, if too many people use the bridge at once, there will be a traffic jam and everyone's enjoyment of the bridge will decrease. However, due to the large capital outlay required for constructing a bridge, and the transactions cost associated with collecting tolls, many bridges are operated by the government and provided as a public good. Stephen Saletta 17:50, 11 November 2007 (CST)