Depreciating it over 30 years is probably reasonable, but automatically counting replacement as an unfunded liability is way too conservative. Heavily traffic

Depreciating it over 30 years is probably reasonable, but automatically counting replacement as an unfunded liability is way too conservative. Heavily traffic roads will need replacing at least every 30 years. But in my college down, they had side streets made of brick that has lasted over 80 years. Things like water mains and sewerage pipes have a lifetime of 100 years or more. A lot of the systems are now due up for replacement for the first time and it will cost a lot. But it won't have to be done again again in our lifetimes.