The METRORapid Silver Line is a bus rapid transit line in Houston, Texas operated by METRO. Opened August 23, 2020, the line connects the Uptown area of Houston, with dedicated lanes over nearly the entire length of the corridor. It serves the Northwest Transit Center, 8 stations along Post Oak Boulevard in Uptown, and the Westpark/Lower Uptown Transit Center. On internal METRO documents, the METRORapid Silver Line is designated as Route 433.

The Metropolitan Transit Authority of Harris County is a major public transportation agency based in Houston, Texas, United States. It operates bus, light rail, bus rapid transit, HOV and HOT lanes, and paratransit service in the city as well as most of Harris County. It also operates bus service to two cities in Fort Bend County, and to Conroe in Montgomery County. The Metro headquarters are in the Lee P. Brown Administration Building in Downtown Houston. In 2023, the system had a ridership of 77,189,800, or about 232,800 per weekday as of the fourth quarter of 2023.