The severe impact of roadway fatalities has remained a significant concern for researchers in recent years. As of 2015, traffic fatalities were the leading cause of death for individuals between the ages of 15 and 20 years old and a significant safety concern for drivers over the age of 65 years old (otherwise known as the “vulnerable” driving population). Intersection-related crashes have also remained prevalent in these demographic categories. Through four primary crash data evaluations, this dissertation explores the safety implications on the “vulnerable” driving population in the Commonwealth of Massachusetts. Through the utilization of newly developed crash data linkage methodologies, spatial and temporal crash analyses, infrastructure design elements, and traffic operations impacts, this research investigates the critical improvements and needs of left-turn intersection infrastructure. The integration of statewide crash data has the potential to assist researchers and practitioners by providing data trends and quality concerns, ultimately assisting in policy decision-making. A need exists to evaluate these potential safety countermeasures (i.e. crash analysis methodologies and infrastructure elements) for left-turn intersection infrastructure in the Commonwealth of Massachusetts, particularly taking into consideration the factors of driver behavior variability and heterogeneity. The intent of this research is to evaluate the existing left-turn infrastructure at signalized intersections, using Massachusetts as a framework, to investigate their safety impacts on the vulnerable driving population. The findings from this research will address these statewide concerns specifically, while these results have the potential to benefit other states and municipalities with similar standards and data accessibility.