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CHAPTER 4
Performance Measures
for Rural DRT
The research underlying this TCRP project identified more than 60 different performance
measures that have been used to evaluate DRT service, with 16 or so measures used more com-
monly. But one does not need a litany of measures to capture the important aspects of DRT per-
formance, and six measures have been selected as the key measures for the Guidebook, given that
one of the objectives of the project was to select a limited number of measures.
4.1 Key Performance Measures for Assessing Rural DRT
The six measures selected for the Guidebook for assessing rural DRT performance are identified
in Table 4-1 and discussed in this section. Depending on the results of those measures, a rural DRT
system may need to delve deeper into certain aspects of its operations, examining more detailed
data and assessing additional measures to address questions or questionable performance.
Importantly, rural DRT systems must consider the extent to which their mission influences
their day-to-day performance. When a rural system is tasked with serving the needs of riders who
are transit-dependent, its DRT service will often include lengthy trips for critical purposes with
limited opportunity for shared-riding. Its performance measures will then reflect lower produc-
tivity and higher cost per passenger trip than might otherwise be the case.
Passenger Trips per Vehicle-Hour
Passenger trips per vehicle-hour measures the productivity of a DRT system. Many consider
productivity to be the most important single measure of DRT performance, assessing the system's
effectiveness.
As a performance measure, productivity captures the ability of the DRT
system to schedule and serve passenger trips with similar origins, destinations, productivity = total passenger trips
and time parameters, using the least number of in-service vehicles and hours. ÷ total vehicle-hours
This is the essence of shared-ride, public DRT service.
However, there are various important factors that affect the ability of a
DRT system to be productive: the size of the service area; the distribution of
residential areas and destination areas; and the patterns of riders' trips, including the extent of
group trips. Particularly for rural DRT systems, large service areas with dispersed trip patterns
make it harder to effectively schedule two or more riders on the same vehicle; this will result in
a lower productivity. The extent to which the rural DRT system serves pre-scheduled group trips
will also impact productivity, such as group trips to the senior center or other frequented desti-
nation. If there are limited group trips--that is, few opportunities to schedule riders on the same
23
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24 Guidebook for Rural Demand-Response Transportation: Measuring, Assessing, and Improving Performance
Table 4-1. Six key DRT performance measures
selected for Guidebook.
1. Passenger Trips per Vehicle-Hour
2. Operating Cost per Vehicle-Hour
3. Operating Cost per Vehicle-Mile
4. Operating Cost per Passenger Trip
5. Safety Incidents per 100,000 Vehicle-Miles
6. On-Time Performance
vehicle at the same time for travel to a common destination--this will also mean a lower pro-
ductivity.
Other factors that impact productivity include the level of no-shows and late cancellations,
scheduling efficiency, dispatcher skills, and ability to schedule trips in real-time, vehicle opera-
tor experience and familiarly with the service area and their passengers' trip-making patterns,
and the operating environment including the roadway network and geographic barriers that
impact that network.
The type of DRT service--particularly whether it functions as ADA paratransit--also affects
productivity because ADA regulations have effective limits on the flexibility that a DRT system
has to maximize shared riding. This also may mean a lower productivity. Some of these are exam-
ples of uncontrollable factors affecting the performance of DRT systems. Such factors impacting
DRT performance are discussed in more detail in Chapter 5.
From a DRT performance perspective, the emphasis on productivity stems in great part from
the fact that small changes in productivity can be very cost effective. Larger changes can be even
more cost effective.
The productivity measure can be calculated with either revenue-hours or vehicle-hours in the
denominator. For this Guidebook on rural DRT, the measure uses vehicle-hours, in keeping with
one of the project's objectives to use NTD data definitions.
To the extent that vehicle-hours are generally fixed, at least in the short run, while revenue-
hours occur only during passenger service, using vehicle-hours to measure productivity may
provide a better indication of how well vehicle resources are being used over the course of a day,
week, or month (5).
However, in the guidebook for urban DRT (TCRP Report 124), the productivity measure uses
revenue-hours as the denominator. Direct comparisons, then, between productivity data
included in TCRP Report 124 and that included in this Guidebook for rural systems are not valid
since deadhead time is included in the measure for rural DRT systems. In some cases, deadhead
can be a significant proportion of vehicle-hours.
For those rural DRT systems that collect revenue-hours data, productivity can be calculated
using revenue-hours. Use of revenue-hours for measuring productivity has generally been used
for demand-response transportation where revenue-hour data are available. Revenue-hours are
typically used for measuring fixed-route productivity as well. Moreover, since revenue-hours are
less than vehicle-hours, the productivity figure will be higher when revenue-hours are used as
the numerator in the measure--passenger trips--is divided by a smaller number.
Productivity is sometimes measured as passenger trips per mile. Given the low passenger vol-
umes on DRT relative to mileage, this ratio usually results in a number less than 1. Such resulting
numbers are not particularly logical given that an actual passenger trip is not less than 1; passenger
trips per hour is an easier number to visualize.
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Performance Measures for Rural DRT 25
Performance Considerations
If a rural DRT system has a lower performance on passenger trips per vehicle-hour than desired,
it should look to various possible reasons, only some of which the system can affect:
· A large service area, where passenger trips are lengthy;
· Low density of passengers within the service area;
· System policies that allow riders to travel to destinations beyond the primary service area,
for example, service to a distant medical facility;
· Significant deadhead time, related to service area size and long-distance trips;
· Service policies and scheduling practices that facilitate individualized trip-making ("one-to-
one" trips rather than "few-to-one" or "many-to-one" trips);
· Limited dispatch control that lacks the tools to manage service operations and respond to
changes on a real-time basis;
· High rates of no-shows and late cancellations;
· Scheduled vehicle-hours that are not aligned with ridership demand; and
· Less-than-reliable vehicles, with excess breakdowns, requiring replacement service to be
deployed.
Operating Cost per Vehicle-Hour
Operating cost per hour is a key cost efficiency measure, assessing the financial resources
needed to produce a unit of service, defined for this measure as an hour of service. What does it
cost the DRT system to put service on the street? This measure, however, does not evaluate use of
the DRT service; because of this, it should be assessed in conjunction with the measure passenger
trips per vehicle-hour or other ridership use measures.
Similarly to the productivity measure, practices vary as to whether the mea-
sure uses revenue-hours or vehicle-hours in the denominator. Since the produc- operating cost per vehicle-hour =
tivity measure has used vehicle-hours, this measure also used vehicle-hours. total operating cost ÷ total
vehicle-hours
Performance Considerations
The elements in this measure are (1) the DRT operating costs, with the
major components of costs related to staff labor and vehicle operations and their maintenance
and (2) the amount of DRT service provided as measured by vehicle-hours. For a rural DRT sys-
tem, deadhead time may have a significant impact on operating costs if large amounts of time
are needed to travel to and from pick-up and drop-off locations at the start and end of passen-
ger service.
There are various reasons that a DRT system's performance on operating cost per vehicle-hour
may not meet objectives, including
· Costs for labor, particularly vehicle operators, since these compose the largest share of tran-
sit staff;
· Costs for maintenance from an older fleet, from problem vehicles, from accidents, and
from fuel costs;
· High costs for administration or other overhead;
· High proportion of paid hours for vehicle operators related to vehicle-hours of service--
that is, a significant proportion of operator payhours that is attributed for cost items other
than providing passenger service (e.g., administrative efforts);
· High fringe benefits costs for items such as vacation, sick leave, family leave, and med-
ical benefits;
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26 Guidebook for Rural Demand-Response Transportation: Measuring, Assessing, and Improving Performance
· Costs for significant amounts of deadhead time because of service-area size and/or long-
distance trips; and
· Inefficient number of vehicle-hours, resulting from a poor service design or from schedul-
ing practices.
Labor is a major cost center. For the transit industry in general, labor including fringe bene-
fits may account for up to 70% to 80% of total operating costs, with the majority of employees
working in vehicle operations and vehicle maintenance. The labor rates paid to vehicle opera-
tors and mechanics are somewhat controllable, but will depend on the local job market and
wages paid for similar positions at competing organizations. For some DRT systems, the rates
may be influenced by a labor contract.
Maintenance is an important functional cost center. Based on NTD data for the transit indus-
try in general, vehicle maintenance may account for up to 20% of operating expenses. DRT man-
agement has some control over this factor, but costs will also depend on the type of vehicles, their
age, and the vehicles' operating conditions--the latter of which is influenced by service-area
characteristics and weather.
Operating Cost per Vehicle-Mile
Operating cost per mile is another service efficiency measure often used for performance assess-
ments, either in addition to or instead of operating cost per hour. While cost per hour is often
the more important measure because the largest proportion of costs (wages and salaries) is paid
on an hourly basis, the measure operating cost per vehicle-mile is included for rural DRT sys-
tems since rural systems with limited data reporting practices are more likely
to report vehicle-mile data than vehicle-hour data.
operating cost per vehicle-mile =
As a cost efficiency measure, operating cost per vehicle-mile assesses the
total operating cost ÷ total
financial resources needed for the rural system to produce "vehicle-miles."
vehicle-hours
Similarly to the related measure, operating cost per vehicle-hour, this mea-
sure does not evaluate the use of those vehicle-miles, so the measure should
be assessed along with measures of DRT utilization.
Performance Considerations
Factors that influence the operating cost per vehicle-mile measure for DRT include the oper-
ating costs as well as number of miles operated, which is influenced by the average speed of ser-
vice and deadhead requirements, among other factors. Reasons that a rural DRT system may
have a relatively high operating cost per vehicle-mile include some of the same as listed above
for the measure operating cost per vehicle-hour:
· Relatively high operating costs stemming from high costs for labor, maintenance, and/or
administration;
· Costs for significant amount of deadhead miles because of service-area size and/or long-
distance trips; and
· Low average operating speed, which could result from a number of factors, including
excess dwell times at riders' pick-up and drop-off locations or other factors which slow
down service--for example, weather-related factors such as fog or poor road conditions.
While the primary cost factor is the hourly operating cost, the measure cost per vehicle-
mile is impacted because the costs are spread over a smaller number of miles.
For urban DRT systems, high operating cost per vehicle-mile may result in part from excess
traffic congestion, which slows down average operating speed, but this is less a factor in rural areas.
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Performance Measures for Rural DRT 27
Operating Cost per Passenger Trip
Operating cost per passenger trip is a critical cost-effectiveness measure. It
combines elements of the first two measures--operating cost per vehicle-hour operating cost per passenger trip =
and passenger trips per vehicle-hour, relating productivity to the hourly oper- total operating cost ÷ total
ating cost. passenger trips
As a composite measure, a DRT system may have low operating costs but if
productivity is also low, the operating cost per passenger trip may be relatively
high. Conversely, a DRT system may have a relatively high cost on a vehicle-
hour basis, but if its productivity is high, the cost per passenger trip may be low.
Performance Considerations
A key element of this measure is productivity. Efforts to improve the cost per passenger
trip measure should first focus on increasing the number of passenger trips served within
given resources. Reasons that a DRT system might show high operating cost per passenger
trip include:
· High operating costs:
Costs for labor, particularly vehicle operators;
Costs for maintenance from an older fleet, from problem vehicles, from accidents, and
from fuel costs, and
High administrative costs.
· Low productivity:
Large service area where passenger trips are lengthy;
Low density of passengers within the service area;
System policies that allow riders to travel to destinations beyond the primary service area;
Significant deadhead time related to service-area size and long-distance trips;
Service policies and scheduling practices that facilitate individualized trip-making
("one-to-one" trips rather than "few-to-one" or "many-to-one" trips);
Limited dispatch control that lacks the tools to manage service operations and respond
to changes on a real-time basis;
High rates of no-shows and late cancellations; and
Scheduled vehicle-hours that are not aligned with ridership demand.
Safety Incidents per 100,000 Vehicle-Miles
Safety needs to be a primary concern for all transit systems, including DRT. Rural DRT sys-
tems should track and monitor their safety record and make adjustments as needed to ensure
safe operations. As a performance measure, the safety incident rate can be seen as one that incor-
porates an assessment of both service operations as well as passenger service quality. The safety
of the DRT system may not be an attribute that passengers consider each day that they ride the
DRT system, but safety is a dimension of customer service quality.
Calculation
Given the different ways the DRT systems define and measure safety and their accident rates,
it was determined that the Guidebook use the NTD definitions to assess safety. As described in
Chapter 3, these are very specific definitions.
The performance measure uses the sum of NTD safety incidents, which is a required Rural
NTD data element, divided by 100,000 vehicle-miles. The measure compares the raw number of
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28 Guidebook for Rural Demand-Response Transportation: Measuring, Assessing, and Improving Performance
NTD safety incidents with the miles traveled by the system, which places the raw number into
the perspective of miles traveled by the system.
However, since the reporting thresholds for NTD safety incidents are rela-
tively high (e.g., for a property damage incident, the reporting threshold is
$25,000 worth of damage), rural systems should monitor safety incidents of all
safety incidents per 100,000 vehicle-
types and distinguish between preventable and non-preventable accidents,
miles = [(NTD reportable safety
without regard to a pre-determined dollar threshold. When assessing this more
incidents) ÷ (total vehicle-miles)]
detailed safety data, comparisons over time for the individual rural system will
x 100,000
likely be more meaningful than comparisons to peer systems since individual
system definitions of accidents and preventable versus non-preventable vary.
Performance Considerations
A DRT system's performance on safety can be improved by ensuring that vehicle operators
are well trained, vehicles are well maintained, and operating policies and procedures support safe
operations day to day. Lower than expected or desired performance on safety may result from a
variety of reasons:
· Limited vehicle operator training and/or retraining;
· Inexperienced vehicle operators;
· Vehicle issues such as the vehicle type or design and their condition;
· Scheduling practices that result in a system speed that forces vehicle operators to rush,
which then increases opportunities for accidents;
· Environmental factors such as bad weather; and
· The system's commitment to safety and efforts to communicate that commitment to all its
employees.
On-Time Performance
On-time performance is an important measure of service quality from a
on-time performance = DRT rider's perspective. On-time performance measures the reliability of the
(total on-time trips, including system: does the vehicle arrive for the pick-up when it was promised? While
no-shows) ÷ this measure may get more attention at urban DRT systems that operate ADA
(total completed trips + no-shows + paratransit, it is important for all DRT systems. Rural systems should routinely
missed trips) monitor and assess their on-time performance.
On-time performance may also be important at the drop-off end. In fact,
timeliness at the destination end may be more important for riders with time-
sensitive trips such as to work or medical appointments. DRT systems should
consider assessing on-time performance at the drop-off end for time-sensitive trips, those with a
pre-determined "appointment" time. This would be a separate assessment since only those trips with
an appointment time would be included for this assessment. However, even if a DRT system sched-
ules a rider's trip to ensure timeliness at the destination, the system needs to give the rider a pick-up
time (or time window) so that the rider can be ready when the vehicle arrives.
As discussed in the last chapter, the definition of "on-time trips" varies among DRT systems.
Data collection also varies although most rural systems use vehicle operator-reported data from
operators' manifests.
Calculation
On-time performance can be calculated based on data for all trips (which may require more
data processing time unless the system has MDTs) or on a sample of trips. For a rural system that