Surface Transportation and Public Area Security Act of 2017 This bill reauthorizes for FY2018-FY2022 (1) the public transportation security grant program, (2) the law enforcement reimbursement agreement program, (3) visible intermodal prevention and response teams, (4) explosives detection canine teams, and (5) surface transportation security inspectors. The Department of Homeland Security (DHS) shall (1) establish a law enforcement officer reimbursement agreement program, and (2) increase by at least 200 the number of state and local law enforcement-led explosives detection canine teams trained and certified by the Transportation Security Administration (TSA) dedicated to surface transportation security. DHS shall annually develop risk-based priorities based on risk assessments that consider threats, vulnerabilities, and consequences. The TSA may establish a task force to identify and develop an innovative technology or capability with the potential to enhance transportation security. DHS shall (1) prioritize the assignment of officers and intelligence analysts from the TSA and DHS to locations with participating fusion centers in jurisdictions with a high-risk surface transportation asset, (2) ensure there exists a national mechanism for an individual to report suspicious activity in a transportation facility, and (3) submit an assessment of threats to the transportation sector. A "fusion center" is a collaborative effort of two or more agencies that provide resources, expertise and information to the center with the goal of maximizing their ability to detect, prevent, investigate, and respond to criminal and terrorist activity. DHS shall (1) establish a working group to promote collaborative engagement between DHS and stakeholders to develop non-binding recommendations for enhancing security in public areas of transportation facilities, and (2) disseminate best practices to enhance security against the threat of a vehicle-based terrorist attack.