United States
Environmental Protection
Office of Air and Radiation
Washington, DC 20460
EPA 420-R-93-006
February 1993
Federal Test Procedure
Review Project:      ^ M
Status  Report


             Federal Test  Procedure Review Project;

                              Status Report

                              February, 1993
                             EPA 420-R-93-006
                            Certification Division
                          Office of Mobile Sources
                          Office of Air & Radiation
                   U.S. Environmental  Protection Agency
DISCLAIMER: Although the information described in this status report has been funded in part by the
United States Environmental Protection Agency, it has not been subjected to the Agency's peer and
administrative review processes. It is being released for information purposes only and could be used in
potential regulation development  No official endorsement should be inferred.     ^:.; .*;:-,;-


                    Ov«rvi«w and Background

     The cornerstone  of  the  Clean Air Act (CAA)  is the effort to
attain and maintain National Ambient  Air Quality Standards       .
(NAAQS).  Regulation  of  emissions from on-highway,  area,  and
stationary sources  prior to  enactment of the Clean Air Act
Amendments of  1990  has resulted in significant emission
reductions from these sources.   However,  due to factors such as
the growth in  air pollution  sources,  including dramatic increases
in vehicle miles tr.aveled (VMT),  many air quality regions have
failed to attain the  NAAQS,  particularly those for ozone and
carbon monoxide  (CO).
     The Clean Air  Act,  as amended (CAA or Act) contains numerous
provisions that are intended to remedy these continuing air
quality problems.   As part of this.effort, Section 20-6 (h) of the
CAA requires the Environmental Protection Agency  (EPA) to "review
and revise as  necessary" the regulations governing the Federal
Test Procedure (FTP)  to  "insure that  vehicles are tested under
circumstances  which reflect  the actual current driving conditions
under which motor vehicles are used,  including conditions
relating to fuel, temperature,  acceleration, and altitude."
     The FTP is the test procedure used to determine  compliance
of light-duty  motor vehicles with federal emission standards.L
The FTP is conducted  on  preproduction vehicles during the motor
vehicle certification process,  used to establish that each
vehicle is designed to comply with the appropriate standards  for
its full useful life. It is also used to test production line
and in-use vehicles for  compliance with emission  standards.
     The procedure  provides  a way to consistently and
repetitively measure  concentrations of hydrocarbons,  oxides  of
nitrogen, carbon dioxide/ and carbon monoxide emissions  which
occur when a vehicle  is  driven over a simulated urban driving
trip.2  The principal elements  of the test are designed, to test-'
the evaporative and exhaust  emissions under  several  simulated
situations.  Evaporative emissions are tested  after  heating the
fuel tank to simulate hea€xhg by the sun  (the  diurnal test)  and
again after the car has  been driven and parked with  a hot engine
(the hot soak  test).  Exhaust emissions are  measured by  driving
the vehicle  (placed on  a dynamometer) on  a  simulated urban
driving trip under  two  conditions: with a cold start designed to
'-, The  regulations that encompass  -the  many aspects of the HTP, are generally
  contained in 40 :CFR  Part. 86, Subparts A and B.   .  -             . .  -

: For a', detailed discussion of the  development  of this cycle," see: Kruse, r.cr.a.l
E.,  and  Thomas  A. Huls, SAB  Paper #730553 "Development  of the federal "rear
Driving. Schedule," 1373.  A speed-time trace of this cycle .is contained, i.n-4: :~:
? art 36,-Appendix I...    •    •••'','          "    .   . .

             '  •" '.--'          -   -  2  -  '         ''•••"-   ..."  .

represent a morning startup after a long soak (a  period  of non-
use) and then following a hot start that takes  place  after the
cold start test while the engine is still hot.  The FTP  also
encompasses all factors relevant to vehicle testing,  such as
fuel, vehicle preconditioning,  ambient temperature and humidity,
aerodynamic loss,  and vehicle inertia simulations.  In addition
to evaporative and exhaust emissions,  the FTP is  also used in
evaluating fuel economy.
     This status report addresses the progress  EPA has made to
date in complying with the CAA provision and the  status  of future
research efforts.   The first section,  "Areas of Potential
Concern," discusses the four general areas of concern with the
FTP noted in §206(h), the basis for each concern, and the
remedies that have been or are being implemented  by EPA  to date.
The remainder of this report discusses the research program being
conducted by the Agency regarding in-use driving  behavior.

                 Ar«»»  of Potential  Conc«rn

     It is a basic premise that motor vehicle emission levels
determined through the FTP should adequately reflect  in-use
vehicle emissions.  If in-use driving modes exist that generate
significant amounts of emissions that are not reflected on the
FTP, then the anticipated benefits from motor vehicle standards
are not being fully achieved.
     It is also basic that no test procedure can reasonably
duplicate all in-uae conditions.  The overall goal of the
Agency's review of the FTP is to aid  in determining  whether or
not the'FTP should be modified to reflect  in-uae conditions not
currently found in the teat  and, if so, what modifications should
be made.  To meet this goal  it is not enough to  simply  examine
factors such as ambient  temperature ranges,  in-use fuel
characteristics, or driving  patterns.   For  example,  Qualitative
evidence has existed for years that certain types of actual
driving behavior are not represented  on the FTP, such aa high
acceleration rates.  However,  it would  be  counterproductive to
modify  the FTP unleaa two  conditions  are met.  Firat, the driving
behavior or other condition  not  represented properly by the FTP.
should  contribute a  significant  amount  to  motor  vehicle
emissions.  If it doea  not,  then modifying the FTP would  incur
substantial coata and disruption with little or  no air  quality
benefit.  Second, any modification to-the  FTP  should be expected
to promote design improvements to  vehicles and thereby  create
real improvements in controlling  in-use emissions.   If  the
current FTP is already  effective  in reducing emissions  during  the
non-FTP driving or other conditions,  then modifying  the FTP  would
again  incur substantial costs  with little or no  air  quality
benefit.  Even if off-cycle emissions exist that are not  properly
controlled by the FTP,  it  is critical to ensure  that FTP

modifications wiir actually  promote:the proper, design
improvements.   The Agency  believes this approach is a  reasonable
way to implement Section 206(h)'s requirements.     .
   •   Section 206(h) of the Act specifically requires that  EPA
consider four potential areas  of concern: fuel, temperature,
acceleration,  and altitude.  The Agency has identified.several
•other'potential areas of concern relating to driving, behavior:
speed,  cold starts , (frequency  and driving behavior), trip  length,
time between trips, and road grade..
"l.  Gasoline.           •
      The composition of  the gasoline used for the  FTP (commonly
 referred to as indolene)  was established by regulation over 20
 years ago.3  While it was representative of in-use fuel  at  the
 time,  commercial or in-use  fuel properties have  changed
 significantly since then,  in some cases having a major impact on
 vehicle emissions, both  tailpipe and evaporative.4  Studies
 conducted during the 1980' s indicated that vehicles  tended to
 emit higher emissions  using commercial gasoline  than indolene,
 particularly through evaporative losses.  To  address this
 concern, EPA -established volatility limits for gasoline and
 alcohol blends.  These regulations capped the allowable Reid
 vapor pressure for  commercial gasoline during the summer months .
 The -second phase of these controls became effective in the summer
 of  1992. 5   As a result of these actions, the emissions of a
 vehicle fueled with indolene are more representative of the in-
 use emissions results  of a vehicle fueled with  commercial
 gasoline. ;...-.-. -.'•".  --.   , / • . - -  . : . :••.  ."'.'' ..'--.'- • ' •    .   '•   • .- '     .

 '    .    ...    "    '  '".--,.  ••• ,.„_•""•'."' ": ".      .  *   "' -   -        - - "-"ft1 * '  * ' .
 II; Diesel fuel,     -'-r,5: •:   .'-•..'l-.'^k; ..-..,-•-.'• .- ' •-.•„  v;.;: •?. ^ :- ..:.-'   . .'
      The AgencyV has: ^aisO^aken: steps to ;reduc« th* sulfur  content
                  "fu|»i^  F^                                 -7/
                        '  ~ ''   '                  '
 III.  Alcohol and other -fuels.  -                        •,.-•"
  .    The Agency  promulgated regulations in 1989 which established
 emission standards and test procedures for vehicles  fueled with
 methanol and proposed similar  regulations in 1992  for vehicles
"-! :4-p' CFR Ba-rt'. 86-Section 86.113-94.            .'  .   -.:_ -- V<  -   '  •

 1-Evaporative emissions include diurnal, hot soak, .refueling.,-.and running 1 = 3ses .

 ':55 FR 23658 ..(June, 11, '• 1.3.90) ,,  -     .   ;.   ,         .-"":.,-r. '  '

 <--57;-FR.-l-35'.35- (May""",  1332), .: .--'_.  ' -  -.•;;-"•  ..' •    . ,Y '".'' '.-".•'.- .'.   -  •" '- . ,.''  -

        •;;..-  . :--"', _.;•;. .-'  ;-. ::,^.  - _:'•;•_: 4., _ '" '  :    ' ;'..."•;• '•:-- '; •"•'••-.•.-•

fueled with compressed natural gas and liquefied petroleum gases.
At this early stage of alternative fuel development, it is
-mpossible to know what the real-world fuel compositions will be
for any of these fuels when used in automotive applications.  In
each of these rulemakings, EPA has avoided adoption of narrow
fuel specifications, specifying instead that test fuels be
representative of typical in-use fuels.
     These recent requirements established for in-use fuel appear
in general to satisfy §206(h)'s requirements regarding fuel use
in the FTP.  In addition, the Agency is also addressing the use
of representative fuels in the Certification Short Test
rulemaking, for which a proposed rule is expected to be published
in January.

Temperature                                         „,_,_•<.
     The FTP is conducted between 68 and 86 degrees Fahrenheit,
and includes a cold start in  its driving cycle.7  Vehicle
emissions after a cold start  increase at cold«r  temperatures  as a
richer mixture is employed to ensure sufficient  fuel vapor  for
combustion'to-occur.  In  addition, colder temperatures  lead to
longer warm-up times.  This is not a major concern  for  ozone,
which is primarily  a summertime phenomenon, but  it  is  for CO.
Most CO exceedances occur from December to March and over half
occur at temperatures below 45 degrees Fahrenheit.
     To reduce the  emissions  generated from motor vehicles  during
cold temperature operation, EPA recently  issued 20°F  CO emission
standards and test  procedure. These regulations were  issued on
July 17, 1992 and are phased  in beginning with the 1994 model
year 8  The regulations also  established interim temperature
defeat,device criteria to maintain proportional CO emission
control between the 20 degree standard and the warm temperature
standards.  These regulations insure  that the Agency's test
procedures properly reflect the  impact of temperature on CO
emissions.  As the  cold  CO  rules  will  prevent emission step-
functions  just below  68  degrees  that  could also impact
hydrocarbon  (HC) emissions, they  will  also insure that the FTP is
representative of HC  emissions at colder temperatures.
     At warmer temperatures the  primary emission concern is
increased  fuel evaporation.   The Agency is in the process  of
revising its evaporative test procedures to address a number of
concerns,  including temperature.   The final regulations  are
expected to  specify ambient test temperatures of 95°F.   These  new
test  requirements  should insure that vehicles   can control
evaporative  emissions for most in-use events.
      The Agency  believes that the above FTP changes appear in
  An enable scar* is considered to be a "cold"  start  if it is preceded by a l:r:
  uninterrupted scak,  such as those starts that .occur after an overrnght 3.a.-.

  *-> «•?. 31333  iJuly  L~, 1332) .

general to satisfy §206(h)'s -requirements regarding temperature
conditions in the FTP.   ."'".". -.'•'•- ' ^ - .'f '-'••'•'     , ;    ',-.',  .' -   ;  ' ;

Altitude  •'..'.".       ':    *       •   •>'     :    \  v :::'.:'       :.
     It has long been recognized that at high  altitude  locations,
if there is no compensation for the  lower air  density,  engines  ..
tend to run rich more frequently and emit more HC and^CO
emissions. Virtually.all  light-duty  vehicles have been  required
to meet emission standards, at both low and high altitude without  •
adjustment or modification since the 1984 model year.   Light-duty
trucks and light-duty vehicles have  had separate high altitude
standards since the  1982  model year.  Regulations published on
June 5, 1991 will require light-duty trucks to meet emission
standards at both low and high altitude without adjustment  or
modification beginning with the 1997 model year.'  The.:  cold
temperature CO regulations require that both  light-duty vehicles
and light-duty trucks meet the standard at both low and high
altitude without modification.  The  FTP does  not  specify an
altitude range in which the test.must be conducted.   In effect,
the regulations allow the FTP to be  conducted at  any  altitude  and
this, in .fact,,, occurs,         /                  :-  ..-."'•; • .• - - .".-   .
     As with fuel and temperature parameters  for  the  FTP,  EPA
believes that the above requirements appear  in general  to satisfy
§206(h)'s requirements regarding  altitude  conditions  in the FTP.

     Current technology vehicles  have  achieved impressive
reductions in emissions during normal  operation,  primarily due to
catalyst technology  development^ Catalyst conversion
efficiencies  (i.e. the rate  at which HC  and CO are  oxidized into
carbon dioxide  (C02)  and  water vapor,  or  oxides  o£  nitrogen (NOx)
are reduced to nitrogen and  oxygen)  in a  modern,  properly
operating, warmed-up vehicle  can simultaneously exceed 98% for
HC, 99%,. for CO anA; 9G%  f or NOx,  This includes typical-transient
urban traffic^ O^rS^bhVsucibt as  that represented -by the FTP._,.__
However, theser simu3^»neous  ciitalyst conversion fifficieneies are
only .achieyabl* \w.itS^|i'Jthree-wmy .catalyst in a veryr narrow -range
of fuel/air™ia*ios£^                              air  requirement
for complete'combustion" ^(called stoichiometry) .  Thus>^  modern,
properly operating vehicles  are  designed to operate at
3toichiom«try" as mucjv as  possible during the FTP.
     There are two types  of  operation that make it difficult to
operate""an engine it stoichiometry.   The first type  of operation
is cold starts.  Fuel must be vaporized with  air to  combust
properly.  When the  engine  is cold there is not enough heat to
properly vaporize the fuel  and additional fuel must  be added  for
proper'operation, , Cold start emissions are- also increased due  to
the  lack,of  conversion  activity, in the catalyst until  it heats  up
 '• . 3 6 FR . 25 7 2 4 (June SV  1:

 (little catalyst activity occurs below about 600  degrees
Fahrenheit).    Thus, emission rates during cold starts  can be  20-
lOO^times the emission rates during stoichiometric  operation.   In
fact, the vast majority of emissions from modern, properly
operating vehicles on the FTP occur during the first  10%  of  the
test, before the engine and catalyst have warmed up.   Thus an
important question is whether the cold start portion  of the  FTP
properly reflects the proportion of time vehicles  actually  spend
in the warm-up mode.
     The second type of operation that makes it difficult to
operate an engine at stoichiometry is high engine loads.  High
loads on an engine running at stoichiometry can dramatically
increase engine and catalyst temperatures.  These elevated
temperatures greatly increase NOx emissions and can cause engine
knocking and/or damage to the catalyst.  The performance  and
driveability of an engine under high load can be improved by
running with a richer mixture of fuel.  Thus, to prevent
overtemperature damage to the catalyst and insure the best
possible driveability and performance, manufacturers often design
their vehicles' to run rich at high loads.  While this reduces NOx
emissions, it increases HC and CO by almost the same 20-100 time*
factor as cold start operation.  An important question then is
whether a significant amount of high load operation occurs in-use
that is not reflected on the FTP.  Due to the nonlinear nature of
the emission rates, this amount of driving could actually be
fairly small and still have a significant emission impact.
     There are a wide variety of in-use  factors that impact the
amount of time vehicles spend in either  a warm-up or high-load
mode.  Warm-up factors include distributions  of trip length,  time
between trips (referred to as "soak time"),  ambient air
temperature,  initial idle time, and driving  behavior.  Factors
that can cause high loads on a vehicle  include high acceleration
rates, high speeds, road grades, air  conditioning  operation,  or
some combination of factors  (such  as moderate acceleration  up a
moderate road grade). Complicating the  assessment  is the fact
that different vehicles have very  different  calibration
strategies.  Thus,  the impact on emissions  of the  exact  same
driving behavior may vary widely from vehicle to vehicle.
     To properly address the emission impact of driving  behavior,
very detailed and  statistically valid data  are needed for both
actual driving conditions and the  impact of this driving on
^missions  from a wide variety of vehicles.   When the CAA was
amended in 1990, very little  information was available on  any of
*-he driving behaviors or  conditions  discussed in this section,  or
on their  emission  impacts.   It  was therefore necessary for  EPA tc
conduct a  research program  on  actual driving behavior and the
emissions  impact of such  driving.
          on  Driving Behavior
      Past qualitative assessments have concluded that the FT?
 effectively  represents in-use emission reductions from vehicle

 emission  standards  (i.e. any/off-cycle emissions did notoccur'
 with  enough  frequency to have a significant impact).   However;
 the larger the baseline emissions, the smaller the impact from
 off-cycle emissions.  Other CAA mandates such as Tier I emission .:
 standards and longer useful life will all serve to reduce'the
 baseline  emissions measured by the FTP.  If adopted,  .Tier II ,
 emission  standards would have a like effect,  Thus, any off-cycle
 emissions will become relatively more important in the future.  ,
 The research program undertaken by the Agency is designed both to
 quantify  any emission impacts from off-cycle driving behavior and
 to.provide information needed to determine whether or not EPA
 should make  regulatory changes to the FTP.
      The  program developed by the Agency to evaluate driving
 behavior  contains three basic components.  First, to determine
 how vehicles are actually driven, an extensive amount of vehicle
 monitoring   was conducted.  This is described in the next
 section,  "In-Use Assessment of Driving Behavior."  Second, the
 data  from the vehicle monitoring is being analyzed to determine
 cycle and trip information and the impacts of different factors
 on driving behavior and to develop driving cycles that represent
 the complete range of actual driving behavior.  This'part of the
 program is described in the section., "Analysis of Driving
 Behavior  Data."  The third part of the- program involves assessing
 the emission impact of the driving behavior.  This is being
 pursued both by development of a computer simulation model  and by
 vehicle testing, as described in the section, "Emission
 Assessment of In-Use Driving Behavior."                .
     Thes« three sections are designed to describe the entire
 research  program from start to finish.  -The  final  section of this
 report('"Status and Plans," identifies which portions  of the work
 have already been completed, which are currently  in progress, and
 which are still to be done.  It outlines the status  of the  tasks
 discussed in the sections on the research program and  sets  up a
 general schedule for work that has not yet been  completed.

           In-UM A«9««MMnt of Driving Behavior

 Outreach ••"  •.-.:'-        '"-•..-•'•'''- • " • '  •  •  "'.-•• ^' .-:'•'
      From the start of the FTP study,  EPA has made a concerted
 effort to inform all  interested parties  of  our plans to evaluate
 in-use driving behavior and to solicit  input and participation.
 The first public meeting was held  at  the EPA National  Vehicle and
 Fuel  Emissions Laboratory on December  20,  1990  to discuss EPA' s
 plans for the FTP study.  This meeting was  well  attended and
 generated considerable  interest  among  motor vehicle..  ,
 manufacturers.  A second meeting  was  requested  by auto
•representatives to  allow them to  respond to several issues
 discussed at 'the initial meeting,   In  these subsequent meetings,.
 the auto  manufacturers  demonstrated a willingness to work with  •

EPA to ensure a thorough and successful study.   As  a  result of
these meetings, an Ad Hoc Panel on the FTP was  formed by the
Motor Vehicle Manufacturers Association (MVMA)  and  the
Association of International Automobile Manufacturers (AIAM).
     As part of the outreach effort for the FTP Study,  EPA held
discussions with the State and Territorial Air  Pollution Program
Administrators (STAPPA)  and the Association of  Local  Air
Pollution Control Officials (ALAPCO)  members during the first
part of 1991.  These talks led to the establishment of  a
Cooperative Agreement with New York State's Albany  Emission
Laboratory  (AEL). The agreement called for AEL  to conduct vehicle
testing to examine engine and catalyst cool-down temperatures  and
their relationship to motor vehicle emissions.

Driving Behavior Data Acquisition
     A centerpiece of EPA's approach to the FTP Study is  the
examination of how vehicles are operated in the real  world.  Early
on, EPA reviewed existing data sources on current driving
behavior and' found them deficient for our task.  To truly
understand driving behavior EPA felt that it was critical to
collect real-time driving data on a representative sample of
drivers.  The MVMA/AIAM Ad Hoc Panel on the FTP supported this
approach and talks were held to discuss a cooperative research
effort.                                      .        „,««.,,_
     A meeting was held in Atlanta, Georgia in June_of 1991 to
discuss options for conducting surveys of in-use driving
patterns.  The meeting included experts from industry,
government, and academia. Two EPA contractors  gave presentations
on alternative driving survey approaches.  As  a result of the
meeting-, EPA concluded that two complementary  approaches were
necessary; data were to be collected using both a  chase car
approach and an instrumented vehicle approach-.- Each approach is
described below.
     The next  step was the selection of cities to  survey.
Resource constraints limited the  surveys  to  two  cities.  In
addition, the  two driving survey  methodologies restricted the
choices for possible cities.  For example,  to  minimize potential
bias in the  selection of  drivers  and vehicles,  the instrumented
vehicle study  required recruiting drivers from centralized
Inspection  and Maintenance  (I/M)  stations.   The chase  car
approach dictated that a  city  possess  an  up-to-date
transportation network model.   These requirements  limited  the
choices to  a. handful of prospective  cities.  The Agency  selected
Baltimore,  Maryland  and  Spokane,  Washington.   Baltimore
represents  a major urban  ozone non-attainment  area and is  within
the Northeast  corridor.   In contrast,  Spokane  is characteristic
of a smaller,  cold CO non-attainment area.
     Additional  information on in-use driving  behavior has  been
collected  in Los Angeles, California and Atlanta,  Georgia.  The
California  Air Resources  Board (CARS)  has utilized the chase car
approach to collect  data tn-Los Angeles.   The  Agency and GARB

                               - 9 -

 have  coordinated activities... from the^'start  of  the FTPl.Study; the,,,
'CARB  chase- car. study  closely  paralleled EPA's  chase; car efforts
 and was  conducted by  the  same contractor.                  •   ,
      The Atlanta work was done in coordination with EPA's "Air and
 Energy Engineering Research Laboratory (AEERL)  of, the, Of fice of  "
 Research and. Development  (ORD) .   AEERL is conducting research in
 Atlanta  as part of a  long-term project to improve mobile source
 emissions inventories and emissions  modeling.   With financial
 support  from AEERL, ah instrumented  vehicle survey  was conducted
 in  Atlanta during the summer  of 1992 using  the 3-parameter
 dataloggers developed for the FTP study. This  study, along with  ^ ;
 the Los  Angeles study,  will improve  the regional representation
 of  the original ih-use; driving surveys.

      The instrumented vehicle study  consists of placing
 instruments in individuals' privately-owned vehicles.   :
 Datalogging devices are mounted inconspicuously under the
 vehicle's hood and data are collected for  about one week.   To
 minimize potential sampling bias, drivers  are recruited randomly
 from  centralized I/M  stations using  a formal   /        l ; ,
 recruitment/replacement protocol.        ~        •
      To  date>  a major accomplishment of the FTP study is the
 cooperation and support of both MVMA and AIAM.  The instrumented
 vehicle  component of  the  FTP  study in Baltimore and Spokane was a
 joint, effort with MVMA and AIAM.  After EPA designed the basic
 program  and established a contract with Radian Corporatibh to
 conduct  the testing,  the  MVMA/AIAM Ad Hoc Panel on the FTP
 contributed funds and specialized instrumentation to the
 contractor to augment our base program.  The MVMA/AIAM Ad Hoc
 Panel also agreed to  allow SPA to manage th« entire d*t*
 collection effort.  The joint goal was to instrument  144 vehicles
 in  each  city, for a total of 288 vehicles,  as described below:
                                _    '•'.'.             ~~*•**• i^t -
      -" ~  100 ~  ' BPJt sponsored 3-param«t«r vehicles
      -   ,  »98 *   MVMH/AIAM sponsored 3-param«t«r  vehicles
            9J°   _ MVMA/AIAH sponsored 6-param«t«c  vehicles

           28'a  ~   Total

      The 3^-frjfcraawiter instrumentation  measures  vehicle speed,
 engine sp««d^ in revolutions per minute (rpm),  and  manifold
 absolute pr*iisur«.  The  6-parameter instrumentation also  collects
 information on coolant temperature, throttle  position,  and  the
 air/fuel ratio.  The latter  instrumentation packages were custom-
 designed by each manufacturer.   The  3-parameter instrumentation
 was developed by Radian  Corporation.   At the  conclusion of  the
 program,'the 55 3-parameter  dataloggers were  turned over  to EPA
 for future use.   ' ..••'--•-• .-'-  ." • .".  "'  '  -. ' .-     •-- .: : ;- -  •  '  ';; '.  •" •
      A pilot study was conducted in Spokane on January 6-10,
 1992. Alternative solicitation and incentive strategies  were

-  -'  ""• •. ':  ."V:"  . " ••";- '  •:.->;--'r/:"--.". ''•-' 10 --•';  •--'•:•'•  :;• ::"••:• .-•.-'  :    .

evaluated and 4 vehicles were instrumented.   Data  collection for
the full study in Spokane began February 3 and was completed the
first week of March.  The Baltimore study followed,  with data
collection completed in early April,  1992.   "~

Chase Car Study
     The traditional chase car approach typically  involves
driving an instrumented vehicle in a manner that simulates the
driving behavior of the vehicle being "chased." The methodology
used by the Agency in this project- is an enhanced  version of this
traditional approach.  The new chase approach uses a chase car
which is instrumented with a grill-mounted laser rangefinder.
With the laser rangefinder, it is possible to accurately
calculate the speed of a target vehicle without the chase car
having to emulate the target car's driving behavior.  The chase
car is driven over representative road routes, which are
generated using a transportation network model. Tho strengths  of
this approach are its ability to collect driving patterns data
for a large sample of vehicles and the virtual elimination  of  the
bias introduced by the drivers knowing that their  driving
behavior is being monitored.                          ""
     The laser rangefinder was a modification of  a new
technology; a hand-held laser gun used by police  for identifying
speeders.  Pilot tests of the laser-equipped chase car were
conducted in the summer and fall of 1991.  Data collection for
Baltimore study began in November of 1991; the contractor,  Sierra
Research, drove a total of 248 routes finishing December 20.
Following enhancements to the laser and other on-board electronic
equipment, Sierra Research carried out the CARB-sponsored Los
Angeles'chase car study in the Spring of  1992.  The Spokane chase
car study was completed by the end of July, 1992.

3UEL Research
     The current FTP implicitly assumes that  all  starts are
either "hot" starts  (represented by an engine  off time of 10
minutes before restart) or "cold" starts  (represented by an
overnight soak before restart).  However, almost  half of all
restarts in-use occur after a soak period of  10 minutes to 4
hours, for which the engine and catalyst  may  be in  intermediate
temperature conditions.  The New York  State Automotive Emission
Laboratory, under a grant  from EPA, conducted testing to study
the effect of soak time and ambient conditions on engine and
catalyst temperatures.  To date, AEL has  drafted  4  progress
reports which presented results of the  testing.   This information
will provide  insight into the condition  of  the engine and
catalyst during starts that fall  into  these  intermediate
temperature conditions.

             Analysis of Driving B«h*vior Data
                              - 11 -


'*E^                                                 edited .

                                         a^^-- ;'^t>at a suspected
                                          ^ojr sxibsequent •
    rltiessj^                                                      . •  .
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                                    :p^rehensively describe  .
                                              ' *iti*dy--.of-.•/:•    \  -';
                                                 ' on' three, ''•••• '••'" •
                        sp^^^dacce^leration patterns,     -
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          fractions of time spent at high levels  of  speed,  and
          acceleration and specific power.

     In the chase car study,  route measures are similar to  the
trip measures given above.  In addition,  statistics  are
calculated on the portion of survey time during which the laser
was locked on a target vehicle .                        • •  •
     Several types of summary measures were requested ' from  EPA' s
contractors.  Measures of location and dispersion (mean and
standard deviation) ,  minimum, and maximum capture the essential
features of a particular sample.  Greater detaiil is  found in
frequency distributions and their associated graphical display.
Because of the concern with the emissions impact of  non-FTP high
speed,  acceleration,  and power,  the upper percentiles of these
distributions are computed explicitly to support more detailed
study of these "extremes" of driving behavior.  Finally, the
combined distribution of speed and acceleration will be tabulated
to enable more detailed study of engine load patterns .
     The driving behavior surveys collected or identified
different factors that could influence driving behavior, such as
type of vehicle, location, and road congestion.  The summarized
data described above will also be broken down by these factors .
Analysis of these breakdowns enables the assessment of potential
bias as well as the relative influence of measured factors on
driving.  For the instrumented vehicle study, criteria needing
examination for impact on driving behavior include;
          vehicle age,
          vehicle performance,
          transmission type,
          time of day and week,
      •  . driver age,
          recruitment site,  and
          observation phase  (first  day or  later) .

Criteria collected by the chase  car study  needing study include:
          road type,
          road grade,
          road congestion level,  and
          target vehicle performance  type.
Survey BJM
     In order to  judge  possible  bias  induced by the data
acquisition methodologies,  the study  includes several types of
comparisons.  For the instrumented vehicles,  the breakdown by
observation' phase is used to  examine:  (.1)  whether survey
participant driving behavior  is  influenced by the presence of the
datalogger; and (2) if  any such  influence diminishes over time.
Another potential concern with the instrumented vehicle data
involves -driver refusal to participate.   Drivers of high-
performance or  luxury vehicles were less likely to agree to have
their vehicles  instrumented.   If these drivers and vehicles have
                              -  13  -

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estimate the difference between emissions  predicted by the FTP
cycle and emissions that occur in actual driving.  Using either
computer models or dynamometer testing, this  assessment requires
the development of one or more driving cycles that are
representative of the real world.  The driving survey data
discussed above will serve as the primary  input to this component
of the project.
     Several approaches to cycle development  currently are under
review.  These vary considerably in level  of  subjectivity.  One
approach, used in developing the current FTP,  is to splice
together segments of real speed patterns that are selected from
the survey data.  A final cycle is obtained by matching summary
features of the resulting speed-time trace with those of the  full
sample.  A virtue of this and related approaches is their basis
in real driving experience that can be reproduced in dynamometer
testing.  The choice of segments and matching criteria  are
potential difficulties.
     A more directly quantitative approach to cycle development
is to generate a vehicle speed-time trace  using Morite Carlo
simulation.  Simulated second-by-second values are chosen
according to statistical criteria derived from the survey  data.
Cycles are subjected to matching criteria in order to  screen out
unsatisfactory candidates.  This ia likely to b« a more efficient
method of producing different cycles, but these cycles  are wholly
"unreal" in comparison to the splicing approach described above.

           Emission  A»««»»m«nt  of In  U»« Driving

Approach                              '                 .   .
     In analyzing data from the  in-use driving surveys it is
essential to consider the emissions impact of  the real-world
driving patterns that are not represented by  th« current FTP
driving cycle.  As discussed, above,  this requires assessment of
a wide range of driving behavior,  factors influencing emissions,
and manufacturer calibration  strategies.  In order to perform
these large scale assessments, EPA is developing a. computer model
which simulates vehicle emissions  over any d«sired driving cycle.
EPA is using the modeling approach because it affords flexibility
in analyzing the emission impact of the driving survey data  and
could allow us  to conduct a  smaller vehicle  testing program.    A
simulation model will  allow  the  emission  assessment of a number
of unedited and/or composite driving  cycles  over a large number
of vehicles with relative ease.   Conversely,  a strict  vehicle
testing-based  approach for an initial assessment of the emission
impact of  in-use driving behavior would limit the assessment to a
small number of composite cycles over a relatively small  sample
of.vehicles, and would not allow the  needed  flexibility  for the
type of  large-scale  assessment desired by EPA.  Vehicle  testing
will be  used during  the course of the emission assessment  effort.
                              - 15 .-

           '  ^,              %,     ^
 in order to validate the results of the computer simulation
 model.  Contingency testing plans to gather basic emission-impact
 information are also, being prepared in case the model proves to
 be too  inaccurate for qualitative analysis.

     The simulation model computes instantaneous fuel and
 emission rates based on instantaneous vehicle speed.  This model
 is currently" being developed as two components, known as VEHSIM
 and VEMISS~. -.""_"          -  -
     The VEHSIM component was  originally developed by GM and
 later-revised by th* Department of Transportation.  The VEHSIM
 model takes instantaneous  (generally  second-by-second) vehicle
 speed inputs and calculates instantaneous  engine speed and  load.
 Thes* calculations of engine speed and load are performed
          vehicle information  regarding vehicle aerodynamics,
            'a^^-i^^9^i  engine  accessories stored:  in  a
                                  '••'-.'''....''              .   " .
         .'siconi in;;prd*ir':tb'v'cai<^iat^"'fuel'.and'emissipn  rates for  an
 instantaneous  engine speed  and load.
     Upon completion of VEHSIM and VEMISS, these  components will
 be linked to produce a fully; functioning model capable of
 simulating instantaneous fuel  and emission rates based on ah
 inputted speed/time  trace.  •
     EPA' s~go*I ia tordafeMsaiafrtfi* emisaioi* impact of actxart
	,ing behavicriMoa technology that ia available today and will
likely be available i» th«~h«xt few yeara.  To thia endr EPA, .
tested_a  flMfe of 29 lat» mpdal, current technology^ _ low mileage
vehicles  which" eove>r- a broad range of vehicle types (both car and
light  truck* .  Th* pbActive is to enable BPX to match, the
driving^cbwr*ct«riatica of any vehicle in the driving aurvey
sample with a representative vehicle froa the 29 vehicle fleet.
     The  Agency has completed the testing and development of
engine map» for each ofVtha 29 vehicles.  Currently, EPA is
wbrkirig to cpa^siile the part libraries for theae vehiclea so that
the  VEHSIM/VEMISS model: will be able to simulate fuel and
emission  ratea using any speed/time trac* input, for each vehicle
' itarm'. Modal'-vi	._
      Before the model can be used to confidently  assess,: the
 emission impact of. in-use driving, a validation of  the  model must

be performed.  This validation effort is  in  progress  and
currently focuses on the component of the model  which simulates
emissions under warm operating conditions.   The  purpose of the
first phase validation is to assess the accuracy of the warm
model and highlight the refinements necessary to improve  the
accuracy of the model.  This is being done by comparing the model
output to actual data over a series of test  cycles, including the
FTP and a high acceleration cycle.  Future validations will
include comparisons of model results to test results  run  using
new test cycles on a single large-roll electric  dynamometer
(which should much more accurately reflect in»use emissions).
Refinements may include improvements to the  engine maps,  part
libraries, and the model itself.  Validation will continue  in  an
iterative fashion for each vehicle as improvements are made.

Cold Modal Development
     Cold start emission simulations also need to be  developed to
estimate the impact of cold start driving behavior and soak time.
Aa the cold start simulation will calculate emissions using the
warm engine-out emission maps as the starting point,  development
of the cold start module is being sequenced behind the warm
component of the model.  Once the warm component is
satisfactorily validated, the cold operation component will be
developed based on existing test data on the 29 vehicles,
integrated into the model, and validated.  Upon completion, the
model will be able to simulate fuel  rate and emissions for an
entire vehicle trip.

                        NFRM D4v*lopii!*nt

     The Agency will  use the analyses  described above in
determining whether or  not the driving cycle  or other aspects  of
the FTP should be revised to properly  represent vehicle  emissions
during actual driving conditions.   However,  in  any proposal to
revise the FTP, EPA   would  also  need to  consider various other
issues, including:
     — Technology assessment
     - Type  of  revision needed
     - Lead  time
     - Cost  and cost  effectiveness analyses
     The  technology assessment includes  determining  the  changes
needed for manufacturers to reduce emissions during  the
identified off-cycle  condition,  the level of reduction achievable
with different  technologies and/or calibration strategies,  and
the feasibility of making the technology changes.  Closely
related  issues  are  cost and lead time,  as greater levels of
technology change  or  added component requirements will increase
the cost  of  the regulation and,  possibly, increase the lead time
needed  for manufacturers to implement the changes.
                               -  17  -

                                                                _ .
                                                            ; would
/. would
                        i-ei,  revisions to th«9
                        of "the; vast array of historical
                           	th% Impact- on CAFS -and"	
                               andards,   It^may be much more cost
                     to establish a hew cycle and standard :gy
- emissions;,:,
                              ^^                                ' -•  " -
                          "standard stringency^ co«ts^^ andi benefits
                          ley^elrof complexity wilt. be .significantly
             €he results  of jthe;^study in regar^i:^ ^he;::l«OT*i of-
                     and  ther type of driving  eheratin  the
                         Status and Plans
- arid plana- to
                                    Xn: order to keep this outline
                          pVi^         -, only::y*ry; 'tirie* statements
                                                   thii^ section is ;


  pr-ivina Behavior
                     Tasks Completed to Date
     Vehicles instrumented:
Spokane -    102 3-parameter
              42 6-parameter
Baltimore -  113 3-pa-rameter
              37 6-parameter
Atl. (ORD) - 110 3-parameter
Chase car:
     Spokane -    249 routes
     Baltimore -  248 routes
     L.A. (ARE) - 202 routes
Data processed (Baltimore and
Summary statistics defined
1st draft data summaries:
  Spokane instrumented veh
  Baltimore instrumented veh
  Baltimore chase car
Cool-down study  (N.Y. AEL):
     6 vehicles tested
     4 progress reports
29 vehicles mapped:
   1990-92, MPI
   40-55 steady state points
   7 cold  start steady state
   Calif,  accel cycle
Data cownloaded to PC
Engine  torque calcualted
Warm emission module written
1st cut evaluation of maps
                         Work in Progress
Trip definition
Bias analyses/correction
Recovery of suspect vehicles
Process Atlanta data
Phase I warm speed/accel
  analysis  (inst. veh.)
Trip definition
   Torque v«rificaiton
   Soakl time emission impact
Compile parts library
Validate warm modeling/maps
  .  (2 vehicles)
Summarize test data - all veh
                               - 19 -

                            By January, 1993

 Complete cooldown analysis  (AEL)    Begin cold  start model       , .
 Analyze:         -~                    development          .     ""' V
    Trip length and soak time       -Enhance part library  data;
    Cold start driving behavior      Validate VEHSIM/part  library
    Warm driving behavior              methodology
                             '        Compare modal data  to VEMISS
..,.-•'.\.-...   '   ''••'  ^ •'•   '-.-' , •'-  v  -•    -   •.,':'•. 'predictions  "     - ' •   •     •  . •
                            ;        Assess modeling effectiveness,
                        .  :             inc. testing validation
                          :  ;  •'*",    Develop contingency test plan

                             By March, 1993

 Develop warm driving cycles     '.    Complie cold start  database
 Analyze/effects of driving          1st cut warm speed/accel
   behavior influences on:             emission  evaluation
     trips  and soak time        -    Compile/validate part libraries
     cold driving        ""          ~   - all vehicles
     warm driving
 Compile draft of driving
   behavior study for review-
 Hold public workshop on analysis                                ''•/..'
   of driving behavior study

-" -  ' .   - " .    '*-.'.-.,'""'  • '   : • ,  • - •    ' ''- -   1   "   •  • .'         , - '     •• "  , ' •" ~^' L  •
 :•'  •''  ''.•.''•;• .•.,..'"'  "•'..."•.'..•.'•• J  By Ray,  1993     •-'..-      • /..   •'.  ".,.,•

 Publish preliminary technical       Validate  warm  VEMISS/maps on
   report;  request public              rest  of vehicles
                           By S«pt«ab«r,  1993
       _               ~ -             Complete enhancements to model
                         " ^          Complete cold start module
                                      Validate model with test data
                                      Assess emission impact of all
                                        driving behavior

                            By November, 1993

 Final study report, including recommendations, ready for internal
 Agency review; begin development  of an NPRM to revise the FTP or a
 notice of intent to not revise the FTP.
                                    - 20  -