The monthly CEO’s report includes a number of “Key Performance Indicators” (KPIs) intended to track various aspects of the transit system. However, the methodology behind some of the KPIs, notably those related to service quality, leaves a lot to be desired. Moreover, information that could track basic issues such as vehicle reliability is not included. This begs the question of whether the indicators exist more as a security blanket (“we have KPIs therefore we are good managers”) than as meaningful management tools, not to mention as reports to the politicians and public.
A telling chart on page 6 of the presentation shows how badly the TTC has drifted from transit industry norms:
The TTC aims to have almost enough vehicles available for service relative to actual needs, and operates with a lower spare ratio than the industry overall. This has two effects.
- When unusual demands for service arise, there is no cushion to roll out extras.
- Vehicles are not maintained often enough to prevent in service breakdowns. This shows up in a mean distance between failures that is very much lower than the industry average.
The situation is actually compounded by an internal measure of service delivery: a garage counts a bus as “entering service” if it makes it across the property line onto the street. Whether the bus runs for an entire day or breaks down a block from the garage, it counts toward service provided. This is complete nonsense, but shows how the construction of a metric can induce behaviour that is counterproductive. Actually keeping the bus in the garage could allow it to be repaired and improve reliability, but that’s not what the garage is measured for.
Moving to a higher spare ratio and more frequent routine maintenance on vehicles is expected to yield better service with fewer in service breakdowns. Late in 2014, the TTC began this shift by slightly increasing spare ratios at each garage, and the MDBF for the bus fleet has risen to 7,000km. This will have to be tracked over a longer time, however, to ensure that the improvement is permanent and can be linked to further increases in spares and maintenance work.
This has a non-trivial cost for the TTC. With a total scheduled service of about 1,500 buses, a 6% increase in spares represents 90 vehicles, or a substantial portion of a typical yearly bus purchase, not to mention a fair amount of garage space.