Document ID: EPA-HQ-OAR-2014-0827-2187
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2016-10-25T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY
                             2000 TRAVERWOOD ROAD
                           ANN ARBOR, MI  48105-2498

									          	OFFICE OF
										AIR AND RADIATION

May, 2016

MEMORANDUM

SUBJECT:	Vocational Vehicle Tire Rolling Resistance Certification Data 

FROM:	Lauren Steele, Environmental Engineer, OTAQ/ASD

TO:	Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles - Phase 2 - Docket EPA-HQ-OAR-2014-0827

Introduction

      This memorandum summarizes model year 2014 vocational vehicle certification data including reported levels of tire rolling resistance and production volumes for many vehicle types, from most vocational vehicle chassis manufacturers.  At the time these data were analyzed, not all manufacturers had submitted their end-of-year production reports.  Notably, of the manufacturers subject to Phase 1 standards, a smaller percent of national production of class 2b-5 vocational vehicles is represented in this analysis than the percent of class 6-8 vehicle production represented.  However, the data do include certification information for over 36,000 light heavy-duty vocational vehicles from five manufacturers; thus, we conclude the data are sufficiently robust for purposes of understanding the distribution of tire rolling resistance levels among the currently offered tires fitted on this weight class of vocational vehicles.  
      
      Light truck (LT) tires are most often fitted on heavy-duty pickup trucks and vans, though they also are used for light heavy-duty vocational vehicles.  Due to the different material properties of LT tires, the agencies adopted a provision in Phase 1 to allow manufacturers certifying vocational vehicles with LT tires to use a 0.87 adjustment factor before entering the tire CRR in GEM.  Because the MY 2014 certification data for LHD vocational vehicles may include some CRR levels to which this adjustment factor may have already been applied, we have considered the available LHD tire data without adjustment.  The agencies have concluded that we do not have a basis to discontinue allowing the measured CRR values for LT tires to be multiplied by a 0.87 adjustment factor before entering the values in the GEM for compliance.
      Based on manufacturer-reported information about trade names of production models as well as transmission codes, the agencies have been able to identify some distinct vehicle applications among the data.  Specifically, the agencies have analyzed the submitted reports to distinguish tire rolling resistance levels for emergency vehicles, cement mixers, school buses, motor homes, coach buses, and transit buses.  Data not distinguished as being associated with one of those vehicle types are collated and presented as a group for other chassis cabs.
      
      Because these data are compiled from detailed production reports that include the CRR of every tire on every vehicle produced, the agencies are able to consider this information in projecting future adoption rates as part of setting the Phase 2 vocational vehicle standards.  In the final rules, the agencies are generally projecting adoption of LRR tires in MY 2027 at levels currently met by 25 to 40 percent of these reported vocational products on a sales-weighted basis.  The rolling resistance levels projected for adoption in MY 2027 for Regional and Multi-purpose vocational vehicles are near the 25[th] percentile of tire CRR distributions presented in this memo for other chassis cabs (see Table 1 and Table 2).  Because vehicles with urban drive cycles will benefit less from reduced tire CRR than vehicles with significant highway operation, we have targeted the 40[th] percentile of tire CRR in each weight class in the MY 2027 technology packages for Urban vocational vehicles.  There are both steer and drive tires on certified vocational vehicles today with CRR ranging from 5 kg/tonne to 15 kg/tonne.  We expect this full range of tires will continue to be available in the market well into the future.

Overview

Table 1 below presents a summary of all drive tire data analyzed, and Figure 1 presents a chart depicting these same data.  Table 2 below presents a summary of all steer tire data analyzed, and Figure 2 presents a chart depicting these same data.

      
  Table 1: Range of Drive Tire CRR (kg/tonne) on MY 2014 Vocational Vehicles
Vehicle Type
                                      Max
                                    90%-ile
                                      Avg
                                    25%-ile
                                      Min
C8 Emergency Vehicle
                                                                           9.40
                                                                           9.42
                                                                           7.98
                                                                           7.22
                                                                           5.41
C8 Cement Mixer
                                                                           9.00
                                                                           7.84
                                                                           7.13
                                                                           6.75
                                                                           6.60
C8 Chassis & Voc Tractors
                                                                          15.00
                                                                           9.26
                                                                           7.77
                                                                        6.89[a]
                                                                           5.10
C6-7 Chassis & Voc Tractors
                                                                          11.00
                                                                           9.15
                                                                           7.82
                                                                        6.89[a]
                                                                           4.90
C2b-5 Chassis
                                                                           9.50
                                                                           8.44
                                                                           7.19
                                                                        6.89[a]
                                                                           5.71
C6-8 School Bus
                                                                          15.00
                                                                           8.69
                                                                           7.14
                                                                           6.33
                                                                           4.94
C2b-5 School Bus
                                                                           9.50
                                                                           9.25
                                                                           8.25
                                                                           7.72
                                                                           6.10
C6-8 RV & Coach Bus
                                                                           8.80
                                                                           6.80
                                                                           6.13
                                                                           5.77
                                                                           5.20
C6-8 Transit/Shuttle Bus
                                                                           9.50
                                                                           7.88
                                                                           6.85
                                                                           6.31
                                                                           5.43
C2b-5 Transit/Shuttle Bus
                                                                           8.90
                                                                           8.35
                                                                           7.86
                                                                           7.59
                                                                           6.63
Note:
[a] This value supports the 6.9 drive tire CRR modeled for Regional and Multipurpose vocational vehicles in MY 2027, as shown in Table V-26 of the preamble.
      
      
      
      
                                       
Figure 1:  Range of Drive Tire CRR (kg/tonne) for MY 2014 Vocational Vehicles 

  Table 2: Range of Steer Tire CRR (kg/tonne) on MY 2014 Vocational Vehicles
Vehicle Type
                                      Max
                                    90%-ile
                                      Avg
                                    25%-ile
                                      Min
C8 Emergency Vehicle
                                                                           9.40
                                                                           7.41
                                                                           6.41
                                                                           5.88
                                                                           5.00
C8 Cement Mixer
                                                                           7.30
                                                                           7.16
                                                                           6.71
                                                                           6.47
                                                                           5.41
C8 Chassis & Voc Tractors
                                                                           9.40
                                                                           7.19
                                                                           6.37
                                                                        6.18[a]
                                                                           4.90
C6-7 Chassis & Voc Tractors
                                                                           9.50
                                                                           7.66
                                                                           6.83
                                                                        6.18[a]
                                                                           4.90
C2b-5 Chassis
                                                                           9.50
                                                                           7.66
                                                                           7.04
                                                                        6.18[a]
                                                                           5.81
C6-8 School Bus
                                                                          15.00
                                                                           7.71
                                                                           6.52
                                                                           5.89
                                                                           4.94
C2b-5 School Bus
                                                                           8.90
                                                                           8.82
                                                                           7.59
                                                                           6.95
                                                                           5.54
C6-8 RV & Coach Bus
                                                                           7.70
                                                                           6.79
                                                                           6.08
                                                                           5.70
                                                                           5.00
C6-8 Transit/Shuttle Bus
                                                                           8.90
                                                                           7.65
                                                                           6.73
                                                                           6.24
                                                                           5.43
C2b-5 Transit/Shuttle Bus
                                                                           8.90
                                                                           8.33
                                                                           7.84
                                                                           7.59
                                                                           6.60
Note:
[a] This value supports the 6.2 steer tire CRR modeled for Regional and Multipurpose vocational vehicles in MY 2027, as shown in Table V-26 of the preamble.
      
      

     Figure 2:  Steer Tire CRR (kg/tonne) for MY 2014 Vocational Vehicles

       
Summary by Vehicle Type

The data for emergency vehicles are from three manufacturers producing a total of 1,284 vehicles.

                                       
     Figure 3:  Steer and Drive Tire CRR (kg/tonne) for Emergency Vehicles

The data for concrete mixers are from two manufacturers producing a total of 438 vehicles.

                                       
      Figure 4:  Steer and Drive Tire CRR (kg/tonne) for Concrete Mixers

The data for school buses are from three manufacturers producing a total of 34,722 vehicles.

                                       
        Figure 5:  Steer and Drive Tire CRR (kg/tonne) for School Buses

The data for motor homes are from three manufacturers producing a total of 6,529 vehicles.

                                       
        Figure 6:  Steer and Drive Tire CRR (kg/tonne) for Motor Homes

The data for coach buses are from three manufacturers producing a total of 1,073 vehicles.

                                       
        Figure 7:  Steer and Drive Tire CRR (kg/tonne) for Coach Buses

The data for transit buses are from four manufacturers producing a total of 3,292 vehicles.

                                       
       Figure 8:  Steer and Drive Tire CRR (kg/tonne) for Transit Buses

The data for other chassis cabs are for 69,502 HHD vehicles produced by five manufacturers;  
67,976 MHD vehicles produced by four manufacturers; and 36,101 LHD vehicles produced by five manufacturers.  

Figure 9:  Steer and Drive Tire CRR (kg/tonne) for All Weight Classes of Other Chassis Cabs

        Figure 10:  Steer and Drive Tire CRR (kg/tonne) for HHD Chassis

        Figure 11:  Steer and Drive Tire CRR (kg/tonne) for MHD Chassis

        Figure 12:  Steer and Drive Tire CRR (kg/tonne) for LHD Chassis