RPI is used to objectively measure the performance of a route relative to other routes within the same service classification. The key performance indicators (KPI), passengers per hour, passengers per mile and subsidy per passenger are compared against a standard in each route category (radial, crosstown, feeder, circulator and express). The standard is set based on the previous fiscal year’s average. Once the indices for each performance measure are calculated relative to each individual route, all values are normalized to a value of one (1).
The mathematical explanation of the RPI calculation is as follows: (See figure 1.)
While an RPI of “1” or greater shows that a route is performing well, calculating the standard deviation of RPIs identified the use of 0.4 as the minimum expectation threshold.
Routes with an index number between 0.4 and 0.9 meet the minimum expectations. Those routes that perform below minimum expectations of 0.4 RPI are either targeted for action directed toward improving performance, or in these difficult economic times, considered for service reductions or even elimination. From a purely cost-effectiveness perspective, RPI is a fine tool, but it does not take into account all of the issues andobligations that must be met by public transit. It also has a limitation in that it cannot identify opportunities for improvement in already high-performing routes. This is where other studies and street level information, such as that provided by the Route Monitoring Committee, come into play.
Analysis showed three routes were all slightly to well below the minimum RPI. Two of these, however, were considered “lifeline” routes to economically disadvantaged neighborhoods and thus, it was decided to leave them as they are despite their poor performance.
Route 23 serving one of the city’s business parks, including two trade schools and eight hotels, had been growing rapidly, but stagnated at 0.3 RPI following the economic collapse in late 2008. Because it had initially shown great potential, we wanted to come up with another solution rather than cut service to the area altogether. An origin-destination survey of bus passengers from 2008 revealed that most everyone riding Route 23 was making two transfers per trip and all were passing through the intermodal transportation center in downtown. It was decided to discontinue Route 23 and instead extend Route 11 to serve the business park from downtown. The extension of Route 11 would allow continued service to the industrial park during morning and evening peak travel periods, would reduce the number of transfers required to reach the industrial park, and save substantial cost while also adding much needed recovery time to Route 11.
Ridership data from fareboxes was evaluated to identify opportunities for frequency reduction. The farebox system keeps track of daily ridership totals, but is also able to stratify boardings by time of day. Route 7, which operated at 30-minute frequency Monday through Saturday until after 10 p.m., was meeting minimum RPI, but overall ridership was comparable to some other routes with only hourly frequency. However, analysis of farebox data indicated that only a handful of people rode after 7:00 p.m. Subsequently, a decision was made to reduce Route 7 to hourly service and eliminate trips after 8:00 p.m. The savings were substantial. Similarly, as farebox information revealed when boardings peaked and declined, it was decided to reduce frequency from half hour to hourly on Route 4 only on Saturdays and on Route 22 weekdays from 9:00 a.m. to 3:00 p.m.
Bus Stop Analysis
Stop-level boarding counts also were used to evaluate portions of routes. Route 25 actually was one of the higher performing routes with an RPI of 1.2. However, on-bus route observation and analysis provided details that allowed planning staff the opportunity to squeeze efficiencies from this route. Temporary staff from a local staffing agency were employed to perform a stop-level boarding and alighting count that confirmed observations that the western portion of the route carried roughly half as many people as the eastern portion. Evaluation of the run-times allowed us to redesign the route so that some buses could turn around at the La Gran Transfer Center, which was approximately the half-way point. That way, they could still provide cross-town service, but effectively reduce frequency to hourly on the western portion where the ridership was lower and leave 30-minute frequency on the eastern portion where higher ridership warranted.