11-17. Two traffic signal systems are being considered for an intersection. One system costs

$32,000 for installation and has an efficiency rating of 78%, requires 28 kW power (output), incurs a user cost of $0.24 per vehicle, and has a life of 10 years. A second system costs $45,000 to install, has an efficiency rating of 90%, requires 34 kW power (output), has a user cost of $0.22 per vehicle, and has a life of 15 years.

Annual maintenance costs are $75 and $100, respectively.

MARR = 10% per year. How many vehicles must use the intersection to justify the second system when electricity costs $0.08/kWh? (11.2)