The Triathlon is an Olympic event that affects the entire city. This STEM paper is to manage the road closure time of a triathlon event in any City who may have a Triathlon event. In order to quantify the Road Closure Impact to meet 5.5 hours of closure time, authors have developed three different models: (1) Ideal Scenario, (2) Practical Scenario, and (3) Potential Scenario. In the first Ideal Scenario, authors applied Minitab descriptive statistics and box plots to optimize the event schedule and sequence among three Triathlon sports (Swim, Run, and Bike). In the second Practical Scenario, authors have managed the risks such as: pre-event preparation time, award ceremony time, dependency on Gender, Age, Category factors, 2000+ players, Safety/Health, etc. In the last Potential Scenario, we have further optimized the Zone Close and Open period. We can minimize the Zone wasted usage (waiting for players) based on the Worst Case Scenario. The biggest selling point of this paper is not just on the Closure Cost reduction, but also on the Safety/Health protection as well as promoting customer service and local business. This event may be completed on the event day, but our excellent customer service can attract more visitors to join the next city event.