Pipeline Safety Improvement Act of 2019 This bill addresses pipeline safety with respect to natural gas and hazardous liquid pipelines. Among other provisions, the bill reauthorizes appropriations through FY2023 for pipeline safety activities; allows for limited safety-enhancing testing programs to evaluate innovative technologies and operational practices testing the safe operation of natural gas or hazardous liquid pipeline facilities; authorizes the Department of Transportation (DOT) to establish a confidential and non-punitive voluntary information-sharing system to encourage collaborative efforts to improve inspection information feedback and information-sharing on best practices, processes, and technology deployments with respect to such facilities; establishes a Liquefied Natural Gas division within the Office of Pipeline Safety of the Pipeline and Hazardous Materials Safety Administration (PHMSA) to ensure the safety and oversight of liquefied natural gas (LNG) facilities, including small-scale LNG facilities, peak shaving facilities, and import or export facilities; creates a Center of Excellence for Liquefied Natural Gas Safety and Training; increases staffing levels in the PHMSA to hire additional personnel with safety expertise; and directs DOT to initiate a study on technologies and measures that reduce the amount of natural gas released during venting and blowdowns of natural gas distribution systems and transmission pipelines.