This indicator measures the percent of transit rail track with performance restrictions. The CTA refers to these as “slow zones”, where trains are required to operate at slower than normal speeds. This could be the result of construction, power systems, signals, or other issues. Elimination of slow zones can help to make transit more competitive by decreasing travel times and improving reliability. This measure is also a federally required performance measure under MAP-21.
Slow zones are currently near the lowest they have been in a decade due to a number of small and large track renewal programs, including 2013 reconstruction of the Dan Ryan branch of the Red Line. Remaining slow zones have a number of root causes. For example, trains reduce speed to protect workers in construction zones.
The rail system may always have some level of speed restrictions for safety around construction and unexpected events. Improvements in transit asset management and system reconstruction can help minimize slow zones. Financial projections for ON TO 2050 include funding being directed toward reducing the state of good repair backlog. These targets are consistent with that plan.
2025: 3.5 percent of track or less with performance restrictions
2050: 3.0 percent of track or less with performance restrictions