2018
Asdfasdf
Transit Fleet Analysis – 2nd Quarter of 2018
Tracking and Evaluating Cost
Implications of Alternative
Fuel Buses and Infrastructure
September 2018
Project Number
FDOT BDV25-943-83
Prepared For
Florida Department of Transportation
— 1 —
Transit Fleet Analysis Quarterly Report – Q2-2018
The Florida Department of Transportation (FDOT) has engaged the Center for Urban Transportation
Research (CUTR) to collect and report performance and cost data related to the operation and
maintenance of transit vehicles in Florida. CUTR made repeated attempts to collect performance and
cost data for both fixed route and paratransit vehicle fleets. Recognizing the difference between the two
types of service, the costs are reported separately for these two types of transit service. Researchers
sent several data requests and data submission reminders to all transit agencies in Florida. Seven Florida
transit agencies submitted relevant cost data covering the second quarter of 2018.
Overall, the data for the second quarter of 2018 covers 1,108 fixed route buses and 212 demand
response vehicles. The summary statistics presented in this document are based on the cost data from
these transit agencies.
— 2 —
Fixed Route Fleet Table 1 presents a summary of physical characteristics of the fixed route transit fleet.
Table 1. Fixed Route Fleet Summary
Power Plant Length Number of Buses
CNG
29’ 3
35’ 15
40’ 113
60’ Articulated 10
Diesel
29’ 54
30’ 14
35’ 201
40’ 489
60’ Articulated 6
Diesel Hybrid
29’ 9
31’ 1
35’ 72
40’ 109
60’ Articulated 8
Electric 35’ 4
Total Fleet: 1,108
Sixty-nine percent (764 buses) of the reported fixed route sample consists of regular diesel buses, while
18.0 percent (199 buses) are diesel hybrid buses. CNG buses account for 12.7 percent of the reported
fixed route fleet. Figure 1 presents a comparison of the diesel, diesel hybrid, and CNG fixed route fleets
by size.
Figure 1. Fleet composition by vehicle size diesel, diesel hybrid, and CNG.
Sixty-four percent of the diesel fleet sample is comprised of 40-foot buses, while 26.3 percent of
vehicles are 35-foot buses. Twenty-nine-foot and 30-foot buses represent 7.1 and 1.8 percent,
respectively. Larger 60-foot articulated buses account for 0.8 percent of the diesel fleet sample.
7.1% 1.8%
26.3%
64.0%
0.8%
Diesel Fleet by Vehicle Size
29' 30' 35' 40' 60' ARTIC
4.5% 0.5%
36.2%
54.8%
4.0%
Diesel Hybrid Fleet by Vehicle Size
29' 31' 35' 40' 60' ARTIC
2.1%10.6%
80.1%
7.1%
CNG Fleet by Vehicle Size
29' 35' 40' 60' ARTIC
— 3 —
Similar to the diesel fleet, 40-foot buses represent the majority of the reported diesel hybrid vehicles,
over 54.0 percent. Thirty-five-foot buses account for 36.2 percent, and 29-foot and 31-foot buses
account for 4.5 and 0.5 percent of the diesel hybrid fleet, respectively. Sixty-foot articulated buses
account for 4.0 percent of the diesel hybrid fleet.
The vast majority (over 80.0 percent) of CNG buses are 40 feet in length, while 35-foot buses and
29-foot buses account for 10.6 and 2.1 percent of the CNG fixed route fleet, respectively. Additionally,
7.1 percent of the CNG vehicles are 60 feet in length.
Table 2 presents a detailed cost and performance comparison of transit buses. For comparison
purposes, reported vehicles’ acquisition costs have been adjusted using the Consumer Price Index (CPI),
reported by the U.S. Bureau of Labor Statistics (BLS), and are presented in constant 2018 dollars.
Table 2. Cost and Performance Comparison of Fixed Route Fleet
Power Plant
Length Number
of Buses
Average Age
(Years)
Average Acquisition
Cost
Fuel Mileage (MPG)
Parts Cost per
Mile
Labor Cost per
Mile
Fuel Cost per
Mile*
Total Operating Cost per
Mile
CNG
29’ 3 3.0 $436,831 4.44 $0.491 $0.825
35’ 15 1.3 $543,764 3.75 $0.088 $0.052 $0.601 $0.800
40’ 113 1.9 $583,863 4.17 $0.095 $0.087 $0.518 $0.700
60’ Artic 10 1.7 3.45 $0.105 $0.208 $0.632 $0.945
Diesel
29’ 54 8.3 $259,303 5.81 $0.169 $0.129 $0.581 $0.914
30’ 14 12.5 $349,342 4.38 $0.250 $0.286 $0.693 $1.229
35’ 201 9.6 $380,309 4.38 $0.202 $0.144 $0.713 $1.157
40’ 489 8.6 $426,670 4.15 $0.191 $0.131 $0.748 $1.087
60’ Artic 6 6.2 $721,410 3.06 $0.317 $0.287 $0.987 $1.591
Diesel Hybrid
29’ 9 6.4 $638,132 6.37 $0.228 $0.212 $0.474 $0.914
31’ 1 6.4 $675,345 6.36 $0.197 $0.233 $0.477 $0.907
35' 72 6.4 $675,680 4.82 $0.257 $0.203 $0.603 $1.062
40’ 109 5.0 $684,860 4.95 $0.214 $0.128 $0.611 $0.952
60’ Artic 8 5.2 $992,244 3.68 $0.216 $0.329 $0.825 $1.370
Electric 35’ 4 4.9 $1,288,250 14.80 $0.008 $0.908
Total Fleet 1,108
* Calculated based on nationwide average prices for fuel (reported by the US Department of Energy).
The data show that diesel hybrid buses have a significantly higher acquisition cost and higher or
comparable operating cost per mile compared to diesel buses. At the same time, hybrid buses provide
better fuel economy than diesel buses. For example, current data indicate that a 40-foot diesel hybrid
bus demonstrates 19.4 percent better fuel mileage than a 40-foot diesel bus (4.95 mpg for diesel hybrid
vs. 4.15 mpg for regular diesel). In addition, 40-foot diesel hybrid buses have 2.4 percent lower labor
cost per mile than diesel buses of the same size ($0.128/mile for diesel hybrid vs. $0.131/mile for
diesel), but also 12.1 percent higher parts cost per mile ($0.214/mile for diesel hybrid vs. $0.191/mile
— 4 —
for diesel). At the same time, 40-foot diesel hybrid buses cost 60.5 percent more to acquire compared to
diesel vehicles of the same size.
Based on the current data sample, CNG vehicles provide significant improvements in costs per mile with
similar or slightly lower fuel mileage compared to diesel buses. Forty-foot CNG buses demonstrate 50.0
percent lower parts cost per mile, 33.2 percent lower labor cost per mile, and 0.4 percent higher fuel
mileage, than comparable diesel buses. Additionally, 40-foot CNG vehicles cost 36.8 percent more to
acquire than diesel buses of the same size. Figure 2 illustrates the comparison of performance and costs
of 40-foot diesel, diesel hybrid, and CNG buses.
Figure 2. Comparison of performance and costs of
40-foot buses.
Vehicle age often plays an important role in how a vehicle performs. Newer vehicles typically perform
better, demonstrating better fuel economy and operating costs per mile. This is true for vehicles of all
propulsions. Additionally, the differential in performance between propulsion types may vary for
different age vehicles. Figure 3 shows the comparison of fuel mileage by vehicle age for 40-foot diesel,
diesel hybrid, and CNG buses.
Figure 3. Comparison of fuel mileage by vehicle age – 40-foot buses.
0.00
1.00
2.00
3.00
4.00
5.00
6.00
MPG Parts Cost/Mile Labor Cost/Mile
Performance & Costs - 40-foot Buses
Diesel Diesel Hybrid CNG
4.7 4.94.7 4.6
4.1 4.03.8 4.0 3.8
4.8
5.25.0 4.9 4.8
5.14.9
5.5
3.5 3.7
4.7
< 1 1 2 3 4 5 6 7 8 9
MP
G
Vehicle Age (years)
MPG by Vehicle Age - 40 foot Buses
Diesel Diesel Hybrid CNG
— 5 —
The data show that the largest differential in fuel mileage between 40-foot diesel and hybrid buses is for
nine-year-old vehicles. A nine-year-old 40-foot hybrid bus demonstrates 43.9 percent better fuel
economy than a diesel bus of the same size and age. At the same time, one-year-old 40-foot hybrid
buses have 1.3 percent lower fuel economy than diesel buses of the same size and age. The data also
show that the differential in fuel mileage between diesel hybrid and diesel buses is decreasing for newer
vehicles. This trend reflects the recent improvements in diesel technology efficiency.
CNG buses typically provide lower fuel efficiency than comparable diesel or hybrid buses. However,
since all 40-foot CNG buses in the current data sample are relatively new (two years old or younger),
little meaningful vehicle age comparison can be performed between CNG and other propulsion types.
The differential in costs per mile is also dependent on vehicle age. Despite large variability, sample data
show that the difference in parts cost per mile between diesel hybrid and diesel buses is generally
growing larger for newer buses, in favor of diesel technology. The differential in parts cost between one-
year-old diesel and hybrid buses is much higher than the cost differential between nine-year-old buses.
Labor costs per mile demonstrate a similar trend in cost differential between diesel and hybrid
technologies, but unlike parts cost per mile, the differential is typically in favor of diesel hybrid
technology.
For example, one-year-old 40-foot diesel hybrid buses demonstrate 40.5 percent higher parts cost per
mile than comparable diesel buses. At the same time, nine-year-old 40-foot hybrid buses demonstrate
11.2 percent higher parts cost per mile than diesel buses of the same size and age. The labor cost
differential, on the other hand, favors newer buses with diesel hybrid technology. One-year-old 40-foot
hybrid buses show 55.5 percent lower labor cost per mile than comparable diesel buses. At the same
time, nine-year-old diesel hybrid buses demonstrate 27.1 percent higher labor cost per mile than
comparable diesel buses. Figures 4 and 5 present the comparison of parts cost and labor cost per mile,
respectively, between 40-foot buses of different propulsion types and ages.
Figure 4. Comparison of parts cost per mile by vehicle propulsion
and age – 40-foot buses.
< 1 1 2 3 4 5 6 7 8 9
Pa
rts
Co
st p
er
Mil
e
Vehicle Age (years)
Parts Cost per Mile by Vehicle Age - 40 foot Buses
Diesel Diesel Hybrid CNG
— 6 —
Figure 5. Comparison of labor cost per mile by vehicle propulsion
and age – 40-foot buses.
For many agencies, fuel is the major part of overall operating costs. The current analysis does not
directly track how much different agencies spend on fuel. Fuel purchase schemes vary from agency to
agency. Some agencies buy at current prices, while others have long-term contracts at a fixed price (or a
fixed markup). To eliminate differences in fuel purchase contracting among the agencies, the current
analysis uses the nationwide average price of fuel to calculate fuel costs for all agencies. The US
Department of Energy reported the following nationwide average prices for the observed period: $3.03
per gallon for diesel, $2.67 per gallon for gasoline, $0.12 per kilowatt-hour (kWh) for electricity, $2.18
per diesel gallon equivalent for CNG, and $2.83 per gallon for propane. Figure 6 shows the comparison
of operating costs per mile for 40-foot diesel, diesel hybrid, and CNG buses, including maintenance and
fuel costs and excluding operator expense.
Figure 6. Comparison of operating costs for different
power plants – 40-foot buses.
< 1 1 2 3 4 5 6 7 8 9
Lab
or
Cost
per
Mile
Vehicle Age (years)
Labor Cost per Mile by Vehicle Age - 40 foot Buses
Diesel Diesel Hybrid CNG
$0.095$0.191 $0.214$0.087
$0.131 $0.128
$0.518
$0.748$0.611
$0.000
$0.200
$0.400
$0.600
$0.800
$1.000
$1.200
CNG Diesel Diesel Hybrid
Operating Costs per Mile
40-foot Buses
Fuel
Labor
Parts
— 7 —
The graph demonstrates that of the three power plants, CNG buses have the lowest parts cost, labor
cost, and fuel cost per mile, as well as the lowest overall cost. Diesel buses have the highest parts cost,
labor cost, and fuel cost per mile, and the highest overall cost of the three power plants.
Thirty-five foot buses are the second most popular size vehicles for all types of power plants in the data
sample. Figure 7 presents the fuel economy comparison and Figure 8 demonstrates the comparison of
parts and labor costs of 35-foot diesel, diesel hybrid, CNG, and electric buses.
Figure 7. Fuel economy comparison of different
power plants – 35-foot buses.
Figure 8. Operating cost comparison of different power plants – 35-foot buses.
Electric buses demonstrate the highest fuel economy among 35-foot buses of different propulsion types,
exceeding diesel and hybrid fuel economy by more than three times. However, electric buses have the
highest parts and labor costs per mile of the compared propulsion types. Thirty-five-foot CNG buses
have the lowest parts and labor costs per mile, but also the lowest fuel economy of the four propulsion
types: diesel, diesel hybrid, electric, and CNG. Thirty-five-foot diesel hybrid vehicles demonstrate 10.2
percent higher fuel mileage and 3.3 percent higher parts and labor costs per mile than comparable
diesel buses. Thirty-five-foot CNG buses have 14.2 percent lower fuel economy and 55.4 percent lower
parts and labor costs compared to diesel buses of the same length. Thirty-five-foot electric vehicles
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
4.38 4.823.75
14.80M
iles
pe
r G
allo
nFuel Economy - 35-foot Buses
Diesel Diesel Hybrid CNG Electric
$0.000
$0.100
$0.200
$0.300
$0.400
$0.500
$0.600
$0.700
$0.800
$0.900
Total Cost/Mile
$0.444 $0.459
$0.198
$0.900
$/m
ile
Total Cost per Mile - 35-foot Buses
Diesel
Diesel Hybrid
CNG
Electric
— 8 —
demonstrate 238.2 percent better fuel economy and more than double the amount of parts and labor
costs than comparable diesel buses.
The graph below combines all the operating costs, including fuel, to demonstrate the overall cost
comparison of vehicles with different propulsion types. Figure 9 presents the comparison of operating
costs, excluding bus operator, for 35-foot diesel, diesel hybrid, CNG, and electric buses.
Figure 9. Comparison of operating costs for different
power plants – 35-foot buses.
As illustrated in Figure 9, 35-foot CNG buses have the lowest parts and labor cost per mile and the
lowest overall cost than all other propulsion types. Thirty-five-foot electric buses have the lowest fuel
cost but the highest parts and labor cost, resulting in overall operating costs that are higher than CNG,
but still lower than diesel or hybrid buses. Thirty-five-foot diesel vehicles have the highest fuel cost and
the highest overall operating costs per mile of the four propulsion types.
The current dataset includes 24 60-foot articulated buses: 10 CNG, 6 diesel, and 8 diesel hybrid buses.
Sixty-foot articulated CNG buses have the lowest parts and labor cost, lowest fuel cost, and lowest
overall operating cost per mile of the three propulsion types. Diesel hybrid buses have the highest parts
and labor cost, the highest fuel cost, and the highest overall operating cost per mile of the compared
propulsion types. Figure 10 shows the comparison of operating costs per mile, excluding bus operator,
for 60-foot diesel, diesel hybrid, and CNG buses.
Figure 10. Comparison of operating costs for different
power plants – 60-foot buses.
$0.198
$0.444 $0.459
$0.900$0.601
$0.713 $0.603 $0.008
$0.000
$0.200
$0.400
$0.600
$0.800
$1.000
$1.200
$1.400
CNG Diesel Diesel Hybrid Electric
Operating Costs per Mile35-foot Buses
Fuel
Parts &Labor
$0.312
$0.604 $0.545
$0.632
$0.987
$0.825
$0.000
$0.200
$0.400
$0.600
$0.800
$1.000
$1.200
$1.400
$1.600
$1.800
CNG Diesel Diesel Hybrid
Operating Costs per Mile
60-foot Buses
Fuel
Parts &Labor
— 9 —
Average vehicle age contributes at least partially to the difference in fuel mileage and costs per mile
between buses of different propulsion types. In addition to being more efficient than diesel buses,
hybrid buses are newer, with an average age of 5.6 years as reported by the transit agencies. Similarly,
CNG buses in this data sample are typically new vehicles, with an average age of 1.8 years. For
comparison, the average age of diesel buses operated by the reporting agencies is 8.9 years. Newer
vehicles typically perform better and cost less to operate than older vehicles.
Table 3 presents the comparison of performance and costs between buses with different power plants
at an aggregate level. For proper comparison, reported vehicle acquisition costs have been adjusted to
constant 2018 dollars using CPI.
Table 3. Aggregate Comparison of Different Transit Vehicle Power Plants
Power Plant Number
of Buses
Average Age
(Years)
Average Acquisition
Cost
Fuel Mileage (MPG)
Parts Cost per
Mile
Labor Cost per
Mile
Fuel Cost per
Mile
Total Operating
Cost per Mile
CNG 141 1.8 $569,179 4.13 $0.095 $0.085 $0.523 $0.711
Diesel 764 8.9 $399,705 4.33 $0.193 $0.137 $0.730 $1.099
Diesel Hybrid 199 5.6 $679,148 4.98 $0.231 $0.160 $0.599 $0.990
Electric 4 4.9 $1,288,250 14.80 $0.008 $0.908
Total Fleet: 1,108 7.4 $470,945 4.46 $0.188 $0.135 Note: Articulated buses were excluded as outliers from the calculation of acquisition costs, fuel mileage, and costs per mile.
The data show that diesel hybrid buses, regardless of size, on average have 14.9 percent better fuel
economy, but also 19.4 percent higher parts cost and 16.9 percent higher labor cost per mile than
regular diesel buses. Hybrid buses also cost on average about 69.9 percent more to acquire than
comparable diesel vehicles.
CNG buses, regardless of size, on average show 4.8 percent lower fuel mileage, 50.9 percent lower parts
cost, and 38.2 percent lower labor cost per mile than diesel buses. CNG buses also have 42.4 percent
higher acquisition cost than diesel vehicles.
Electric buses demonstrate 241.7 percent better fuel economy, but also 143.3 percent higher parts and
labor costs per mile than diesel buses. Electric buses cost 222.3 percent more to purchase than diesel
vehicles.
Figure 11 shows the comparison between buses of all sizes with different power plants.
Figure 11. Comparison of buses with different power plants – all vehicle sizes.
$399,705
$679,148
$569,179
$1,288,250
$0
$200,000
$400,000
$600,000
$800,000
$1,000,000
$1,200,000
$1,400,000
Acquisition Cost
Acquisition Costs - All Buses
4.334.98
4.13
14.80
3.00
5.00
7.00
9.00
11.00
13.00
15.00
17.00
MPG
Fuel Economy - All Buses
$0.370 $0.391
$0.188
$0.900
$0.00
$0.10
$0.20
$0.30
$0.40
$0.50
$0.60
$0.70
$0.80
$0.90
$1.00
Parts & Labor
Parts & Labor Costs - All Buses
Diesel
DieselHybrid
CNG
Electric
— 10 —
Figure 12 summarizes total operating costs, including parts, labor, and fuel costs per mile, for diesel,
diesel hybrid, CNG, and electric vehicles.
Figure 12. Comparison of operating costs between different power plants.
The data show that CNG vehicles have the lowest parts and labor costs per mile and the lowest overall
operating costs per mile of all compared propulsion types. Diesel buses in this data sample demonstrate
the highest fuel cost and overall operating costs per mile if vehicle size is not considered. Electric buses,
regardless of vehicle size, have the lowest fuel cost but the largest parts and labor costs per mile of all
other propulsions. The overall operating costs of electric buses are higher than CNG, but still slightly
lower than diesel hybrid vehicles.
These results should be interpreted with caution since some cost differential may be attributed to
vehicle age rather than performance. For example, the average age of diesel hybrid buses is 5.6 years, of
CNG buses is 1.8 years, and of electric buses is 4.9 years. These types of vehicles are much younger than
diesel buses (average age of 8.9 years). In addition, agencies often prefer alternative fuel vehicles for
bus rapid transit (BRT) routes that typically entail higher speeds and fewer stops. Therefore, duty cycle
differences rather than propulsion technology may account for some of the performance variation
between diesel hybrid, CNG, electric, and regular diesel buses. Finally, the estimates for alternative
propulsion technologies are based on a limited number of data points, limiting the robustness of the
analysis. As researchers collect more data on the performance and maintenance costs of alternative fuel
transit vehicles, the reliability of the analysis will improve.
Weighted Comparison One potential flaw of the methodology used for the analysis could also include employing simple
averages for calculating fuel mileage and costs per mile. This approach ignores the differences between
miles driven by each bus and may result in incorrect calculations, especially when the miles driven by
different types of buses vary significantly. Using weighted averages for calculating MPG and costs per
mile accounts for the difference in mileage. Calculating weighted averages rather than simple averages
assigns higher weights to the calculated parameters based on higher mileage, thus allowing them a
higher influence on the final estimate. Table 4 presents a detailed performance and cost comparison of
$0.188
$0.370 $0.391
$0.900$0.523
$0.730$0.599
$0.008
$0.000
$0.200
$0.400
$0.600
$0.800
$1.000
$1.200
CNG Diesel Diesel Hybrid Electric
Operating Costs per Mile for Different Propulsions
All Vehicles
Fuel
Parts &Labor
— 11 —
transit buses where the calculated parameters (MPG and costs per mile) are weighted by the mileage
driven by each bus.
Table 4. Fixed Route Cost and Performance Comparison – Weighted Parameters*
Power Plant Length Number of Buses
MPG (Weighted)
Parts Cost per Mile
(Weighted)
Labor Cost per Mile
(Weighted)
Total Cost per Mile
(Weighted)
CNG
29’ 3 4.44 $0.332
35’ 15 3.62 $0.086 $0.052 $0.172
40’ 113 4.21 $0.100 $0.099 $0.199
60’ Artic 10 3.45 $0.103 $0.203 $0.306
Diesel
29’ 54 5.21 $0.179 $0.132 $0.331
30’ 14 4.37 $0.250 $0.283 $0.533
35’ 201 4.25 $0.189 $0.119 $0.328
40’ 489 4.05 $0.197 $0.131 $0.338
60’ Artic 6 3.07 $0.312 $0.288 $0.600
Diesel Hybrid
29’ 9 6.39 $0.221 $0.216 $0.437
31’ 1 6.36 $0.197 $0.233 $0.430
35’ 72 5.03 $0.261 $0.159 $0.420
40’ 109 4.96 $0.229 $0.143 $0.372
60’ Artic 8 3.67 $0.230 $0.340 $0.570
Electric 35’ 4 14.55 $0.874
Total Fleet 1,108
*Miles driven by each bus are used as weights in calculating group averages.
The use of weighted averages slightly changes the analysis results, most notably for 40-foot and 35-foot
hybrid buses, increasing slightly the differential in fuel efficiency between hybrid and diesel buses in
favor of hybrids, but also increasing the advantage of diesel vehicles in terms of parts cost and labor cost
per mile. Forty-foot diesel hybrid buses demonstrate 22.6 percent better fuel mileage than comparable
diesel buses when accounting for mileage driven (compared to 19.4% when miles driven are not
considered). Additionally, when weighted averages are used, 40-foot hybrid buses have 16.0 percent
higher parts cost per mile than similar diesel buses (compared to 12.1% when simple averages are used)
and 9.3 percent higher labor costs per mile than diesel buses of the same size (compared to 2.4% lower
labor cost per mile when simple averages are used). The data for 35-foot buses demonstrate a similar
pattern: an increase in fuel mileage and an increase in cost per mile differential in favor of diesel buses
when using weighted averages. The use of weighted averages also decreases the cost advantage of CNG
buses and increases the cost disadvantage of electric buses compared to diesel vehicles.
Figure 13 shows the comparison between 40-foot diesel, diesel hybrid, and CNG buses using weighted
averages to calculate fuel mileage and costs per mile.
— 12 —
Figure 13. Weighted cost and performance comparison for 40-foot buses.
Table 5 presents an aggregate analysis of the entire fixed route fleet using weighted average
calculations.
Table 5. Fixed Route Aggregate Comparison – Weighted Parameters*
Power Plant Number of Buses
MPG (Weighted)
Parts Cost per Mile
(Weighted)
Labor Cost per Mile
(Weighted)
Total Cost per Mile
(Weighted)
CNG 141 4.17 $0.099 $0.096 $0.200
Diesel 764 4.15 $0.195 $0.131 $0.338
Diesel Hybrid 199 5.06 $0.241 $0.154 $0.396
Electric 4 14.55 $0.874
Total Fleet 1,108 4.25 $0.198 $0.133 $0.342 *Miles driven by each bus are used as weights in calculating group averages.
The analysis shows that when accounting for miles driven, diesel hybrid buses of any size generally have
21.8 percent better fuel economy than diesel buses (5.06 mpg for hybrid vs. 4.15 mpg for diesel). Diesel
hybrid buses also have 23.5 percent higher parts cost and 18.0 percent higher labor cost per mile than
diesel buses. CNG buses demonstrate 0.4 percent better fuel economy, 49.2 percent lower parts cost
per mile, and 26.8 percent lower labor cost per mile than diesel vehicles. Electric buses regardless of
length on average have 250.3 percent better fuel economy, but also 158.2 percent higher parts and
labor costs compared to diesel vehicles. Figure 14 graphically demonstrates an aggregate comparison
between buses of different propulsion types regardless of vehicle size using weighted parameters.
Figure 14. Weighted comparison – all propulsion types and bus sizes.
4.05
4.96
4.21
0.00
1.00
2.00
3.00
4.00
5.00
6.00
MPG
Weighted Fuel Economy
40-foot Buses
$0.197
$0.131
$0.229
$0.143
$0.100 $0.099
$0.00
$0.05
$0.10
$0.15
$0.20
$0.25
Parts Cost/Mile Labor Cost/Mile
Weighted Parts & Labor Costs
40-foot Buses
Diesel
DieselHybrid
CNG
$0.338
$0.396
$0.200
$0.874
$0.00
$0.10
$0.20
$0.30
$0.40
$0.50
$0.60
$0.70
$0.80
$0.90
$1.00
Parts & Labor
Weighted Parts & Labor Costs
All Buses
Diesel
Diesel Hybrid
CNG
Electric
4.155.06
4.17
14.55
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
MPG
Weighted Fuel Economy
All Buses
— 13 —
Paratransit Fleet The collected data sample for the second quarter of 2018 contains 212 paratransit vehicles. Of the
reported paratransit fleet, CNG vehicles account for 10.4 percent (22 vehicles), diesel vehicles account
for 25.9 percent (55 vehicles), gasoline vehicles account for 54.2 percent (115 vehicles), and propane
vehicles account for 9.4 percent (20 vehicles). Figure 15 presents the paratransit fleet composition by
vehicle power plant.
Figure 15. Paratransit fleet by vehicle power plant.
Table 6 presents a summary of aggregate performance and costs of paratransit vehicles. Vehicle
acquisition costs have been adjusted to constant 2018 dollars using CPI.
Table 6. Comparison of Paratransit Vehicles of Different Power Plants
Power Plant Number
of Buses
Average Age
(Years)
Average Acquisition
Cost
Fuel Mileage (MPG)
Parts Cost per
Mile
Labor Cost per
Mile
Fuel Cost per
Mile
Total Operating
Cost per Mile
CNG 22 2.1 $129,573 6.87 $0.345 $0.628
Diesel 55 4.5 $98,693 10.24 $0.126 $0.271 $0.321 $0.718
Gasoline 115 3.3 $79,275 8.29 $0.058 $0.048 $0.354 $0.458
Propane 20 2.5 $102,096 7.09 $0.078 $0.169 $0.400 $0.647
Total Fleet 212 3.4 $91,325 8.54 $0.080 $0.130
The analysis indicates that CNG paratransit vehicles demonstrate 32.9 percent lower fuel mileage and
28.7 percent lower parts and labor costs per mile than comparable diesel vehicles. CNG paratransit
vehicles also cost 31.3 percent more than comparable diesel vehicles. Gasoline vehicles have 19.0
percent lower fuel economy, 54.2 percent lower parts cost, and 82.4 percent lower labor cost per mile
than comparable diesel vehicles. Gasoline vehicles also cost 19.7 percent less than diesel vehicles.
Propane paratransit vehicles demonstrate 30.8 percent lower fuel economy, 38.3 percent lower parts
cost, and 37.8 percent lower labor cost per mile compared to diesel paratransit vehicles. Propane
paratransit vehicles cost 3.4 percent more than comparable diesel vehicles. Figure 16 graphically
presents the comparison of performance and costs of demand response vehicles with different power
plants regardless of vehicle size.
10.4%
25.9%
54.2%
9.4%
Paratransit Fleet by Power Plant
CNG
Diesel
Gasoline
Propane
— 14 —
Figure 16. Comparison of paratransit vehicles with different power plants.
Fuel cost is a major expense for many agencies, sometimes accounting for more than half of all
operating expenses, excluding vehicle operator. Adding fuel costs to the comparison provides a more
complete picture of the expenses involved in operating vehicles with different propulsion. Figure 17
shows the comparison of operating costs, including parts and labor and fuel, of paratransit vehicles with
different power plants. Fuel costs were calculated using nationwide average fuel prices published by the
US Department of Energy.
Figure 17. Comparison of operating costs per mile – paratransit vehicles.
Diesel vehicles demonstrate the lowest fuel cost per mile, but also the highest parts and labor cost and
the highest overall cost of all propulsion types. Gasoline paratransit vehicles have the lowest parts and
labor cost and the lowest overall operating cost per mile of all vehicle types. Propane vehicles have the
highest fuel cost all propulsion types, but also the second lowest parts and labor cost per mile.
6.87
10.24
8.29
7.09
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
MPG
Fuel Economy - Paratransit Buses
$0.00
$0.05
$0.10
$0.15
$0.20
$0.25
$0.30
Parts Cost/Mile Labor Cost/Mile
Operating Costs - Paratransit Buses
CNG
Diesel
Gasoline
Propane
$0.283
$0.397
$0.104
$0.247
$0.345
$0.321
$0.354
$0.400
$0.000
$0.100
$0.200
$0.300
$0.400
$0.500
$0.600
$0.700
$0.800
CNG Diesel Gasoline Propane
Operating Costs per Mile - Paratransit Vehicles
Fuel
Parts &Labor
— 15 —
In the current sample, gasoline and propane vehicles show the highest share of fuel cost in overall
operating costs (77.2% and 61.9%, respectively), while diesel vehicles have the lowest share of fuel cost
in overall operating costs (44.7%) among different propulsion types.
The most common vehicle sizes in the reported diesel paratransit fleet are 23 feet and 29 feet (each
accounting for 36.4% of the fleet). For gasoline paratransit vehicles, the most common sizes are 25 feet
(76.5%) and 20 feet (15.7%). All CNG paratransit vehicles are 22 feet in length, while all propane vehicles
in this data sample are 23 feet long.
Table 7 presents a detailed cost and performance comparison of paratransit vehicles of different
propulsion types and sizes.
Table 7. Cost and Performance Comparison of Paratransit Vehicles
Power Plant
Length Number
of Buses
Average Age
(Years)
Average Acquisition
Cost
Fuel Mileage (MPG)
Parts Cost per
Mile
Labor Cost per
Mile
Fuel Cost per Mile*
Total Operating
Cost per Mile
CNG 22’ 22 2.1 $129,573 6.87 $0.345 $0.628
Diesel
22’ 13 2.9 $83,911 12.94 $0.069 $0.222 $0.277 $0.569
23’ 20 6.2 $92,615 9.44 $0.142 $0.266 $0.322 $0.730
24’ 2 4.8 $98,488 10.11 $0.114 $0.299 $0.305 $0.718
29’ 20 3.8 $114,400 9.31 $0.148 $0.306 $0.343 $0.798
Gasoline
17’ 3 0.0 $55,220 17.42 $0.148 $0.157 $0.305
20’ 18 5.5 $53,826 12.00 $0.074 $0.052 $0.222 $0.348
22’ 2 5.0 $82,649 6.85 $0.067 $0.208 $0.389 $0.735
23’ 4 2.5 $81,144 6.96 $0.116 $0.196 $0.426 $0.738
25’ 88 2.9 $85,139 7.30 $0.048 $0.038 $0.381 $0.464
Propane 23’ 20 2.5 $102,096 7.09 $0.078 $0.169 $0.400 $0.647
Total Fleet 212 * Calculated based on nationwide average prices for fuel (reported by the US Department of Energy).
In the current paratransit data sample, 22-foot and 23-foot vehicles are common for most propulsion
types. Therefore, the comparative analysis will focus on those types of vehicles.
The data show that for 23-foot paratransit vehicles, propane vehicles have the lowest combined parts
and labor cost per mile and demonstrate the second highest fuel economy of the compared propulsion
types. Diesel vehicles demonstrate the highest parts and labor cost but also the highest fuel mileage of
the compared propulsion types.
A 23-foot propane paratransit vehicle in the current sample has 24.9 percent lower fuel mileage, but
also provides 45.4 percent lower parts cost and 36.4 percent lower labor cost per mile than a
comparable diesel vehicle. Additionally, a 23-foot propane vehicle costs 10.2 percent more to acquire
than a diesel vehicle of the same size. Twenty-three-foot gasoline paratransit vehicles demonstrate 26.2
percent lower fuel economy, 18.6 percent lower parts cost per mile, and 26.2 percent lower labor cost
per mile than comparable diesel vehicles. The acquisition cost of 23-foot gasoline vehicles is also 12.4
percent lower than the acquisition cost of diesel vehicles of the same size.
— 16 —
Figure 18 shows the comparison of fuel mileage and operating costs of 23-foot diesel, gasoline, and
propane paratransit vehicles.
Figure 18. Comparison of operating costs – 23-foot paratransit vehicles.
Figure 19 presents the comparison of performance and costs of 22-foot diesel, gasoline, and CNG
paratransit vehicles.
Figure 19. Comparison of performance and costs – 22-foot paratransit vehicles.
The data show that for 22-foot paratransit vehicles, the diesel power plant provides the highest fuel
economy and the second lowest parts and labor costs per mile of the compared propulsion types.
Gasoline vehicles of that size have the lowest fuel mileage and the highest parts and labor costs per mile
compared to other propulsion types. CNG vehicles have the lowest parts and labor costs per mile and
fuel mileage comparable to gasoline vehicles.
A 22-foot gasoline paratransit vehicle demonstrates 47.1 percent lower fuel mileage and 18.7 percent
higher combined parts and labor cost per mile than a comparable diesel vehicle. Twenty-two-foot
gasoline paratransit vehicles cost 1.5 percent less to acquire than diesel vehicles of the same size. A
22-foot CNG paratransit vehicle demonstrates 46.9 percent lower fuel mileage and 2.8 percent lower
combined parts and labor cost per mile than a comparable diesel vehicle. A CNG vehicle also costs 54.4
percent more to purchase than a diesel vehicle of the same size.
Due to the limited amount of data reported, little further analysis could be performed for demand
response vehicles. As more paratransit data become available, the detail level of the analysis will
improve.
6.96
9.44
7.09
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
MPG
Fuel Economy
23-foot Paratransit Vehicles
$0.116
$0.196
$0.142
$0.266
$0.078
$0.169
$0.000
$0.050
$0.100
$0.150
$0.200
$0.250
$0.300
Parts Cost/Mile Labor Cost/Mile
Operating Costs
23-foot Paratransit Vehicles
Gasoline
Diesel
Propane
12.94
6.85 6.87
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
MPG
Fuel Economy
22-foot Paratransit Vehicles
$0.291
$0.346
$0.283
$0.000
$0.050
$0.100
$0.150
$0.200
$0.250
$0.300
$0.350
$0.400
Parts & Labor
Operating Costs
22-foot Paratransit Vehicles
Diesel
Gasoline
CNG
