How does this affect my trip? CTA Bus Tracker (information service) may be temporarily unavailable late Friday evening 11:00pm through early Saturday morning at 5:00am. The CTA Bus Tracker Web site at http://www.ctabustracker.com (via either the desktop or mobile device versions), the Bus Tracker by Text (SMS) service and information in third-party apps powered by the Bus Tracker API and the CTA Do-It-Yourself Bus Tracker Display application will be affected by this work. Why will Bus Tracker be unavailable? We are performing Bus Tracker system maintenance and upgrade work to improve the accuracy of the estimated arrival information for buses, particularly as they pull out from terminals and garages to begin their routes.