A new highway is to be constructed. Design A calls for a concrete pavement costing $85 per foot with a 16?-year ?life; three paved ditches costing $3 per foot? each; and four box culverts every? mile, each costing $9,000 and having a 16?-year life. Annual maintenance will cost $1,600 per? mile; the culverts must be cleaned every four years at a cost of $400 each per mile.
Design B calls for a bituminous pavement costing $45 per foot with a 8?-year ?life; three sodded ditches costing $1.30 per foot? each; and four pipe culverts every? mile, each costing $2,300 and having a 8?-year life. The replacement culverts will cost $2,450 each. Annual maintenance will cost $2,800 per? mile; the culverts must be cleaned yearly at a cost of $ 220 each per? mile; and the annual ditch maintenance will cost ?$1.30 per foot per ditch.
Compare the two designs on the basis of equivalent worth per mile for a 16?-year period. Find the most economical design on the basis of AW and PW if the MARR is 12% per year.