Steel cable barriers in highway medians are a low-cost way to improve traffic safety without busting state department of transportation budgets. Cable barriers cost $44,000 per mile, compared with $72,000 per mile for guardrail and $419,000 per mile for concrete barriers. Furthermore, cable bar-riers tend to snag tractor-trailer rigs, keeping them from ricocheting back into same-direction traffic. The state of Ohio spent $4.97 million installing 113 miles of cable barriers. a. If the cable prevents accidents totalling 1.3 million per year determine the rate of return that this represents over a ten year study period. Use all three methods tabulated factors a calculator, and spreadsheets.
b. Now determine the rate of return for 113 miles of guardrail if if accident prevention is 1.1 million per year over a period of 10 year. To do so first write the ROR relation and then find I* using a single cell spreadsheet function.