Life Expectancy of Mast Arm Using Survival Analysis

Abstract

Mast arms play a vital role in traffic signal infrastructure, yet their structural integrity can be compromised over time due to environmental exposure. This study applied fully parametric survival analysis to evaluate the life expectancy of mast arms and assess the impact of environmental factors such as temperature extremes and wind gusts. A dataset of 94 mast arms from intersections in Illinois was analyzed using interval-censored survival data, with weather variables sourced from NOAA and IEM. Two models, the Exponential and Weibull Proportional Hazards (PH) models, were implemented. Based on AIC and BIC criteria, the Exponential model was selected as the better fit. Results indicate that higher maximum and minimum temperatures, as well as stronger wind gusts, significantly increase failure risk. Survival functions were developed under baseline, high, and low stress profiles, and predicted remaining life for in-service mast arms ranged from 7 to 27 years. These findings support the use of survival models in infrastructure asset management and emphasize the importance of environmental data in proactive maintenance planning.