Vocational Strawman

December 2015

1 Draft
Overview

2 Draft

 Recommending primary vocational vehicle program to have three 

composite test cycles & three weight class groups

 Regional, Multipurpose, Urban; HHD, MHD, LHD

 Most technology will have different effectiveness over the 

different cycles, as modeled in GEM.

 Technology projected at feasible adoption rates.

 Recommending unique standards for each of 7 vehicle types:

 Motor home, Intercity bus, School bus, Transit bus, Refuse truck, Cement 

mixer, Emergency vehicle

 Simplified program for these vehicles may not have as many segments or 

weight classes: if drivetrain not in GEM, less sensitive to test cycle

 Option to meet primary standards, maybe a non-GEM tech option.
NREL’s Segmentation Analysis

Two distinct clusters were 

identified: one with fewer stops 

and higher avg speeds, other with 

more stops and lower avg speeds. 

A third exhibits characteristics of 

each: multimodal vehicles.

Representative trips were ranked 

by multivariate distance from 

cluster centroid.

The DRIVE tool generated a single 

representative drive cycle for each 

cluster using the 50 most 

representative trips from each 

cluster. 

5 Draft
Key Cycle Metrics

4 Draft

• Aerodynamic speed

• Characteristic acceleration

• Percent of miles accumulated at speeds below 55 mph

• Percent of cycle time running at zero speed

• Number of stops per mile

• Average driving speed

• Maximum driving speed

• Standard deviation of driving speed
Mileage Accumulation Breakdown

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Mileage Accumulation Distribution for Cluster 1: Low Speed

FDNA 1 MOVES 1

7 Draft
Mileage Accumulation Breakdown 

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Mileage Accumulation Distribution for Cluster 2: Multi-modal

FDNA 2 MOVES 2

8 Draft
Mileage Accumulation Breakdown

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Mileage Accumulation Distribution for Cluster 3: High-speed

FDNA 3 MOVES 3

9 Draft
Possible Composite Test Cycle Revisions

8 Draft

Subcategory Transient 55 mph 

Cruise

65 mph 

Cruise

Idle

NPRM

Regional 50 28 22 10

Multi-Purpose 82 15 3 15

Urban 94 6 0 20

% of miles 

< 50 mph

% of miles 50-

60 mph

% of miles > 

60 mph

% of time 

at 0 mph

NREL Findings 

(December)

High Speed 

Cluster

20 24 56 24

Multimodal

Cluster

54 29 17 52

Low Speed 

Cluster

92 7 1 47

Notes: * Day Cab Tractors have 19% weighting of transient cycle

* Weightings would change if used different speed brackets
Chassis Parameters for Logistic Regression

9 Draft

• Two parameters were observed to be highly significant 

predictors of cluster membership:

• Engine speed at 55 mph

• Engine speed at 65 mph

• Three parameters were observed to have some minor 

significance as predictors:

• Conventional drivetrain (vs hybrid)

• Fuel type

• Transmission type (AT vs AMT)

• Others were observed to have no bearing on prediction 

of cluster membership at all:

• Vehicle weight class
Vocational MOVES Population Allocation

10 Draft

Subcategory Long 

Haul

Short 

Haul

Intercity 

Bus

Motor 

Home

School

Bus

Transit 

Bus

Refuse 

Truck

% of Total Pop. 3% 66% 0.2% 18% 8.5% 1% 3%

Regional 100 35 100 100 0 0 0

Multi-Purpose 0 60 0 0 100 75 0

Urban 0 5 0 0 0 25 100

Public Comments

Regional 100 5 100 100 0 0 0

Multi-Purpose 0 90 0 0 ? 0 ?

Urban 0 5 0 0 0 ? ?

N

P

R

M

NREL’s Predictive Model

High-Speed ? 20 ? ? 0 0 0

Multi-Modal 0 10 0 0 ? 0 0

Slow-Speed 0 70 0 0 0 ? ?
NREL Synthetic Transient Cycle

11 Draft

Max speed 52 mph, about 12 minutes total cycle duration.

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113129145161177193209225241257273289305321337353369385401417433449465481497513529545561577593609625641657673689705721

Speed (mph)

Time (s)

EPA Low Speed Transient
Statistical Comparison of Cycles

12 Draft

Cycle Aerodynamic 

Speed

Characteristic 

Accel.

% Miles 

accum < 55 

mph

% Cycle 

Time at 

Zero Speed

# Stops Per 

Mile

Average 

Driving 

Speed

Maximum 

Driving 

Speed

Std. Dev.

Driving 

Speed

ARB Transient 43.36 0.49 100 15.57 1.4 18.2 47.5 13.38

World 

Harmonized 

Vehicle Cycle

61 0.28 100 13.61 1.07 25.98 54.56 19.03

Japanese HD 

Transient (JPJE05) 51.31 0.4 100 25.19 1.62 22.7 54.43 15.94

European HD 

Test Cycle (FIGE) 68.71 0.23 94.46 0 0 36.65 56.61 17.83

NREL Transient 

Cycle 50.99 0.59 100 21.69 2.98 21.31 51.67 16.16

NREL Target 

Statistics: Urban 

Segment

50.59 0.55 96.45 47.30 1.71 22.62 62.39 13.74

NREL Target 

Statistics:

Multipurpose 

Segment

69.14 0.46 64.64 52.40 0.76 33.64 66.85 19.25

NREL Target 

Statistics:

Regional Segment

83.40 0.29 26.47 24.50 0.21 48.57 70.81 19.17
Appendix

Other NREL Material

13 Draft
Fleet DNA Vehicles with Engine Data

Vocation Description Number of Vehicle

Beverage Delivery 40

Concrete 3

Drayage 16

Dump Truck 4

Food Delivery 44

Freight 22

LINEHAUL 73

Linen Delivery 30

Local Delivery 7

Long Haul 12

Mass Transit 27

Parcel Delivery 117

Refrigerated Truck 6

Refuse Pickup 53

REGIONAL HAUL 1

School Bus 8

Snow Plow 9

Tanker 25

Telecom 17

Towing 3

Transfer truck 14

Utility 23

Warehouse Delivery 10

TOTAL 322 564
Fleet DNA vs MOVES Populations

Vehicle Type MOVES 

(% of Vehicles)

Fleet DNA 

(% of Vehicles, (#))

Fleet DNA 

Resampled to 

Match MOVES 

(% (#))

Short Haul 66 59 (631) 84 (631)

School Bus 8.5 24 (254) 11 (82)

Refuse 3 5 (57) 4 (29)

Transit Bus 1 2 (23) 1 (9)

Other* 21.5 10 (108) 0

Total Number (500,000) (1,073) (751)

• In MOVES, Other = Long haul straight trucks, motor homes, intercity buses

• In Fleet DNA, Other = vocational tractors, vehicles on previous slide

17 Draft
NREL’s Logistic Regression model: 

Predicting Cluster Membership

16 Draft

Logistic regression is a method of constructing the 

best fitting model to describe the relationship 

between the dichotomous characteristic of interest 

(dependent variable = response or outcome variable) 

and a set of independent (predictor or explanatory) 

variables.

In this logistic regression, the dependent 

variable was binary or dichotomous, i.e. it only 

contains data coded as 1 (TRUE, success, etc. ) 

or 0 (FALSE, failure, etc.).
Comparison of Source Cycle Cluster Data

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%

of Distance Accumulated Belo

w 55 mph

% of Time Accumulated at Zero Speed

Zero Speed Time (%) vs Distance Accumulated Below 55 mph 

Cluster 3-1 Cluster 3-2 Cluster 3-3 Cluster 3-1 MOVES Cluster 3-2 MOVES Cluster 3-3 MOVES

19 Draft
Comparison of Source Cycle Cluster Data

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Kinetic Intensity (1/mile)

Average Driving Speed (mph)

Average Driving Speed vs. Kinetic Intensity

Cluster 3-1 Cluster 3-2 Cluster 3-3 Cluster 3-1 MOVES Cluster 3-2 MOVES Cluster 3-3 MOVES

20 Draft
Comparison of Source Cycle Cluster Data

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Stops per Milie

Standard Deviation of Speed (mph)

Standard Deviation of Speed vs. Stops Per Mile

Cluster 3-1 Cluster 3-2 Cluster 3-3 Cluster 3-1 MOVES Cluster 3-2 MOVES Cluster 3-3 MOVES

21 Draft