The Highway Safety Manual (HSM) from the United States provides transportation professionals with tools to predict and quantify the safety impacts of road planning decisions. Before the HSM, there were no widely accepted resources for assessing safety impacts, leading to safety considerations being overlooked in projects. The HSM fills this gap by offering methodologies and software tools like SafetyAnalyst and IHSDM to help professionals make roadway decisions based on safety impacts. These tools help in evaluating the effects of design decisions on highway safety and operational efficiency. The HSM aims to improve safety in transportation projects by providing a structured approach to considering and addressing safety concerns.