Fuel Economy in Harris County2007

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Fuel Economy in Harris County-2007

• Graciela Lubertino, PhD

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Reason for Study

• H-GAC contacted by City of Houston to do a
  regional fuel economy study for 2007
• Aim is to determine how much fuel is consumed
  daily and how the mayors plan of reducing fuel
  usage 5 by 2010 can become feasible.

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Calculation Methodology-Inputs

• 2006 Harris county registration distribution
  (TxDOT)- An array of 16 composite vehicle
  (aggregated diesel and gasoline) for a 25 year
  period.
• 2006 regional diesel fractions (TxDOT)- represent
  the fraction of diesel in a composite vehicle
  category.
• 2007 VMT mix data (TTI)- fraction of VMT per road
  type and per 28 vehicle types.
• Fuel economy table for MOBILE6 vehicle type
  (EPA)- per 28 vehicle type and model year.
• 2007 VMT per hour, per vehicle type (H-GAC)
• 2007 VMT per link (H-GAC)

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Relation between 16 composite and 28
disaggregated vehicle classes
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Methodology

• Split of composite vehicle categories
• Reg_Dist LDGV Reg_Dist LDV x (1
  Diesel_Fraction LDV)
• Reg_Dist LDDV Reg_ Dist LDV x
  Diesel_Fraction LDV

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Methodology

• Reg. Dist x VMXam,md,pm,ov Cam, md, pm,
  ov
• (25x28) (28x15) (25x15)
• Ctam, md, pm, ov x MPG Eam, md,
  pm, ov
• (15x25) (25x28) (15x28)
• The VMX matrix represents the percentage of
  28 different vehicle types on the 15 types of
  roads (urban interstate, urban other freeway,
  toll roads, ramps, urban principal arterial,
  urban other arterial, urban collector,
  local-centroid connector, rural interstate, rural
  other freeway, rural principal arterial, rural
  other arterial, rural major collector, rural
  collector, and local intrazonal)

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Methodology

• Eam, md, pm,ov represents the fuel economy
  weighting average over the 25 years distribution
  for the 28 vehicle types on the 15 facility
  types.
• Each element of this matrix was then inverted to
  get gallons/mile and multiplied by the hourly VMT
  (output from IMPSUM program) to get the total
  fuel consumption for each vehicle category, road
  type and hour of the day.

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Hourly VMT and Fuel Economy
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Fuel Consumption and Fuel Economy for the four
time periods
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Daily Fuel Consumption by Time Period
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Daily Fuel Consumption and Fuel Economy for each
of the aggregated roadway types
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Daily Fuel Consumption by Roadway Type
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Daily Fuel Consumption by Aggregated Vehicle
Classes
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Daily Fuel Consumption by Vehicle Type
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Conclusions

• On an average weekday, approximately 5,000,000
  gallons of fuel is consumed in Houston.
• Gasoline consumption is approximately four times
  more than diesel consumption.
• Light duty gasoline vehicles clearly dominate the
  VMT and the fuel consumption.
• The fuel economy is almost constant during the
  day, with the best occurring during peak periods
  and the worst during midday. These facts are
  primarily due to changes in the proportion of
  heavy duty and light duty traffic volumes.
• Diesel traffic tends to be highest on collectors,
  while gasoline vehicles tend to travel the most
  on freeways

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Conclusions on 2002 and 2009 results

• The overall fuel economy improved from 2002 to
  2009 by 1.3 due to fleet turn over and an
  increased of LDG vehicles by 2 and a decreased
  of HDG by 2
• The VMT increased by 19 between 2002 and 2009,
  which shows an increment of 2.7 per year.
• The total daily fuel consumption increased by 18
  from 2002 to 2009 due to the increased in VMT
  since the increase in fuel economy is almost
  negligible.
• The plots for hourly VMT and fuel economy follow
  the same pattern as for 2007.
• Daily fuel consumption by road type increased in
  freeways by 3, while it decreased in arterials
  by 3 from 2002 to 2009. This is mainly because
  the VMT has increased on freeways by 27 from
  2002 to 2009, while the VMT on arterials has
  increased only by 14.

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Further Conclusions

• This study shows that the effect of fleet turn
  over is almost negligible since the CAFÉ
  standards have not change for 20 years.
• Overall fuel consumption and VMT increased by
  about 2.7 per year from 2002 to 2009.

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• Comparison with TCEQ and TX Comptroller data

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Recommendations

• Accelerating the implementation of new CAFÉ
  standards by 2010 instead 2020, making it at
  least 40 mpg.
• Aggressive implementation of transit, hybrid
  vehicles, commute solutions, and moving freight
  by rail.
• To view full report, please go to
  http//www.h-gac.com/taq/airquality/studies/docs/M
  PG_city_documentation_edit.pdf

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Other Air Quality Issues

• Control strategies for On-road and non-road
  mobile sources to be included in the up coming
  SIP for the 1997 8-hr ozone standard (0.08 ppm)
• EPA approved a new 8-hr ozone standard (0.075
  ppm) called 2008 8hr ozone standard
• Working on automated air toxics calculations

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Conformity News

• Done conformity to the 2035 plan on November 2007
• Done a finding of consistency due to changes of
  METRO projects (BRT to LRT) on the 2008-2011 TIP
  on April 2008
• Done a conformity amendment due to revisions of
  the 2008-2011 TIP (projects delayed) on June 2008