1

State of California 

AIR RESOURCES BOARD 

 

Notice of Public Availability of Modified Text 

PUBLIC HEARING TO CONSIDER THE PROPOSED AMENDMENTS TO THE 

EXHAUST EMISSION STANDARDS FOR 2007-2009 MODEL-YEAR HEAVY-DUTY 

URBAN BUS ENGINES AND THE FLEET RULE FOR TRANSIT AGENCIES 

First Public Hearing Date: September 15, 2005 

Continued To: October 20 & 27, 2005 

Public Availability Date: April 28, 2006 

Deadline for Public Comment: May 15, 2006 

At a public hearing held on September 15, 2005, the Air Resources Board (ARB or 

Board) considered amendments presented by staff affecting urban buses owned or 

operated by transit agencies. Staff presented two policy decisions for the Board’s 

consideration: 1) amending the statewide urban bus emission standards and 

2) mandating that all transit agencies operating in the South Coast Air District be 

required to follow the alternative-fuel compliance path. The Board adopted 

Resolution 05-47, which adopted the amendment mandating transit agencies in the 

South Coast Air District to switch to the alternative-fuel path. The Board deferred 

consideration of the amendment to the statewide urban bus emission standard until 

October 20, 2005. 

On October 20, 2005, staff presented modifications to the regulation originally proposed 

in the Staff Report: Initial Statement of Reasons released and made available to the 

public on July 29, 2005. Staff presented three options to the Board: 1) retain the 

current new urban bus emissions standards, 2) align the 2007 and subsequent 

model-year new urban bus engine emission standards with the equivalent model year 

heavy-duty truck engine emission standard, and 3) require all transit agencies to 

purchase/lease only alternative fuel buses. At the conclusion of the hearing, the Board 

adopted Resolution 05-53, in which it approved modified amendments subject to the 

Board’s consideration at an October 27 hearing of a report from the staff on the likely 

effect of one element of the modified amendments. 

At the October 27, 2005 hearing, after considering the staff’s report, the Board adopted 

Resolution 05-61, approving the modifications previously approved with one additional 

modification. The modified amendments align the 2007 and subsequent model-year 

urban bus engine emission standards with the equivalent model-year California heavyduty truck engine emission standards, but require diesel path transit agencies with more 

than 30 urban buses in their fleets that purchase 2007 through 2009 model-year urban 

buses with diesel engines not certified at or below 0.2 grams per brakehorse powerhour (g/bhp-hr) oxides of nitrogen (NOx) engine emission standard to meet specified 

conditions. The conditions require the transit agency to mitigate the NOx emissions 

through retrofitting an existing urban bus or transit fleet vehicle within its fleet with a 
2

level 3 diesel emission control strategy with a 40 percent NOx reduction, and if a device 

is not verified, a minimum of 25 percent NOx reduction, until vehicles in the agency’s 

fleet are retrofitted or are incapable of being retrofitted. 

In accordance with section 11346.8(c) of the Government Code, the Board directed the 

Executive Officer to make the modified amendments and any conforming modifications 

to the regulation for a transit fleet rule available to the public for comment for a period of 

15 days. The Board further provided that the Executive Officer shall consider such 

written comments as may be submitted during this period, shall make such 

modifications as may be appropriate in light of the comments received, and shall 

present the regulations to the Board for further consideration if warranted. 

Board Resolutions 05-47, 05-53 and 05-61, and the text of the 15-day modifications to 

the transit fleet rule are available electronically on the Board’s Internet site at 

http://www.arb.ca.gov/regact/sctransit/sctransit.htm. Copies of these documents can 

also be obtained from the Board’s Public Information Office at 1001 I Street, 

Sacramento, California 95814, (916) 322-2990, or by contacting Ms. Kathleen Mead 

at (916) 324-9550. 

Written comments on the modifications approved by the Board in Resolution 05-61 may 

be submitted by postal mail, electronic mail, or facsimile as follows: 

Postal Mail is to be sent to: 

Clerk of the Board 

Air Resources Board 

1001 “I” Street, 23rd Floor 

Sacramento, California 95814 

Electronic submittal: http://www.arb.ca.gov/lispub/comm/bclist.php 

Facsimile submissions are to be transmitted to: (916) 322-3928 

In order to be considered by the Executive Officer, comments must be directed to the 

ARB in one of the three forms described above and received by the ARB by 5:00 p.m. 

on the deadline date for public comment listed at the beginning of this notice. Only 

comments relating to the above-described modifications to the text of the regulations 

will be considered by the Executive Officer. 

Attachments
15-Day Notice version A-1 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

ATTACHMENT A 

REGULATORY AMENDMENTS 

TEXT OF THE 15-DAY MODIFICATIONS TO: 

EXHAUST EMISSION STANDARDS FOR 2007-2009 MODEL YEAR HEAVY DUTY 

URBAN BUS ENGINES AND THE FLEET RULE FOR TRANSIT AGENCIES 
15-Day Notice version A-2 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

TEXT OF THE 15-DAY MODIFICATIONS 

Amend the following sections of title 13, California Code of Regulations, to read as set 

forth in the following pages: 

Amend: 

Section 1956.1 Exhaust Emission Standards and Test Procedures – 

1985 and Subsequent Model Heavy Duty Urban Bus 

Engines and Vehicles. 

Section 1956.8(a)(2)(A) Exhaust Emissions Standards and Test Procedures – 

1985 and Subsequent Model Heavy Duty Urban Bus 

Engines and Vehicles 

Section 2023.1(a)(5) Fleet Rule for Transit Agencies – Urban Bus 

Requirements 

Section 2023.4(b) Reporting Requirements for Transit Agencies 

Notes: This document is printed in a style to indicate changes to the preexisting 

regulations. The originally-noticed amendments, released in connection 

with the July 29, 2005, Initial Statement of Reasons, are shown in 

underline to indicate additions and strikeout to indicate deletions. 

Modifications, approved by the Board on October 27, 2005, are shown in 

double underline to indicate additions and double strikeout to indicate 

deletions from the July 29, 2005, proposed regulatory language. The 

symbol “* * * * *” means that intervening text not being amended is not 

shown. “[No Change]” means that no changes are being proposed to a 

specified subsection, the text of which is not shown. “[No modification]” 

means that no modifications to the originally-noticed amendments are 

being proposed. 

 The Board approved the modified amendments conditional to the 15-day 

change procedure. This document shows the proposed 15-day 

amendments to the text. 
15-Day Notice version A-3 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

Amend Section 1956.1 to read as follows: 

§ 1956.1 Exhaust Emission Standards and Test Procedures – 1985 and 

Subsequent Through - 2006 Model-Year Heavy Duty Urban Bus 

Engines and Vehicles.

(a) The exhaust emissions from new 1985 and subsequent model heavy-duty 

diesel cycle urban bus engines and vehicles fueled by methanol, natural gas, 

liquefied petroleum gas, and petroleum shall not exceed the following, by 

model year: 

(1) [No Change] 

(2) [No Change] 

(3) [No Change] 

(4) [No Change] 

(5) [No Change] 

(6) [No Change] 

(7) [No Change] 

(8) [No Change]

(9) [No Change] 

(10) [No Modification] 

(11) [No Change] 

(12) 2007 and subsequent – 0.2 g/bhp-hr NOx, 0.01 g/bhp-hr PM, 0.05 

g/bhp-hr NMHC, 5.0 g/bhp-hr CO, and 0.01 g/bhp-hr formaldehyde. 

(b) [No Modification] 

(c) [No Modification] 

NOTE: Authority cited: Sections 39600, 39601, 43013, 43018, 43100, 43101, 43104, and 43806, 

Health and Safety Code, and section 28114, Vehicle Code. Reference: Sections 39002, 39003, 

39017, 39033, 39500, 39650, 39657, 39667, 39701, 40000, 43000, 43000.5, 43009, 43013, 43018, 

43102, and 43806, Health and Safety Code, and section 28114, Vehicle Code. 
15-Day Notice version A-4 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

Amend section 1956.8 (a)(2)(A) to read as follows:

§ 1956.8. Exhaust Emissions Standards and Test Procedures – 1985 and 

Subsequent Model Heavy-Duty Engines and Vehicles. 

(a)(1) [No Change] 

(2)(A) The exhaust emissions from new 2004 and subsequent model heavy-duty 

diesel engines, heavy-duty natural gas-fueled and liquefied-petroleum-gasfueled engines derived from diesel-cycle engines, and heavy-duty methanolfueled diesel engines, and the optional, reduced-emission standards for 2002 

and subsequent model engines produced beginning October 1, 2002, except 

in all cases engines used in medium-duty vehicles, shall not exceed: 

Exhaust Emission Standards for 2004 and Subsequent Model Heavy-Duty Engines, 

and Optional, Reduced Emission Standards for 2002 and Subsequent Model 

Heavy-Duty Engines Produced Beginning October 1, 2002, Other than Urban Bus 

Model-Year Engines Produced From October 1, 2002 tThrough 2006L

 (grams per 

brake horsepower-hour [g/bhp-hr]) 

Model Year Oxides of 

Nitrogen Plus 

Non-methane 

Hydrocarbons 

Optional Oxides 

of Nitrogen Plus 

Non-methane 

Hydrocarbons 

Oxides 

of 

Nitrogen 

Non-methane 

Hydrocarbons 

Carbon 

Monoxide 

Particulates 

2004-2006H 2.4 A,C,E,J 2.5 B,C,E,J n/a n/a 15.5 0.10 C

October 1, 2002-2006 n/a 1.8 to 0.3 A,D,F n/a n/a 15.5 0.03 to 

0.01 G

2007 and subsequent M

n/a n/a 0.2 I 0.14 15.5 0.01 K 

Footnotes A-K [No Change] 

L

 For 2007 and subsequent model year urban bus engines, this section applies. For 

urban bus model-year engines produced from October 1, 2002 through 2006, refer to 

section 1956.1.

M

 For model years between 2007 and 2009, transit agencies purchasing urban buses

and/or urban bus engines shall meet the requirements set forth in section 2023.1.

* * * * * 

NOTE: Authority cited: Sections 39600, 39601, 43013, 43018, 43100, 43101, 43104, 43105, and 

43806, Health and Safety Code, and section 28114, Vehicle Code. Reference: Sections 39002, 

39003, 39500, 43000, 43013, 43018, 43100, 43101, 43102, 43104, 43106, 43202, 43204, 43206, 

43210, 43211, 43212, 43213, and 43806, Health and Safety Code; and section 28114, Vehicle Code. 
15-Day Notice version A-5 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

Amend section 2023.1(a) to read as follows: 

§ 2023.1. Fleet Rule for Transit Agencies – Urban Bus Requirements 

(a) To encourage transit agencies that operate urban bus fleets to purchase or lease 

lower emission alternative-fuel buses, while also providing flexibility to such fleet 

operators to determine their optimal fleet mix in consideration of such factors as 

air quality benefits, service availability, cost, efficiency, safety, and convenience, 

two paths to compliance with this fleet rule are available: the alternative-fuel path 

and the diesel path. 

(1) [No Change]. 

(2) [No Change] 

(3) [No Change] 

(4) A transit agency within the jurisdiction of the South Coast Air Quality 

Management District shall follow the alternative-fuel path. If the transit 

agency had previously stated its intent to follow the diesel path, the 

change to the alternative-fuel path shall be effective on [Insert effective 

date of subsection]. 

(5) Transit agencies on the diesel path with more than 30 buses in their fleets

purchasing model year 2007 through 2009 urban buses that are not 

certified at or below 0.2 g/bhp-hr NOx emission level shall:

(A) Mitigate the increased NOx emissions for each urban bus purchased 

by retrofitting an existing urban bus or transit fleet vehicle within the

fleet with a level 3 particulate matter (PM) verified diesel emission 

control strategy with an oxides of nitrogen (NOx) reduction efficiency of 

at least 40 percent, if available, otherwise, with a NOx reduction 

efficiency of at least 25 percent. This retrofit requirement applies on a 

one-to-one basis until all diesel urban buses and transit fleet vehicles 

within the transit agency’s fleet are either retrofitted or are determined 

to be unable to be retrofitted as specified in (B) below.

(B) Obtain Executive Officer approval for purchasing a 2007 through 2009 

model year urban bus not subject to (A) above by submitting to the 

Executive Officer a report 90 days prior to the delivery of the urban 

bus. The report shall provide information that demonstrates that all 

vehicles in the transit agency’s fleet have been retrofitted or are 

determined to be unable to be retrofitted including when the inability to 

retrofit occurs for reasons other than a device not verified for the 

specific urban bus or transit fleet vehicle engine family. 
15-Day Notice version A-6 

Release Date: April 28, 2006 

Hearing Date: September 17, and October 20 and 27, 2005

(C) Submit annual reports that meet the requirements in 

section 2023.4(b)(4).

* * * * * 

NOTE: Authority cited: Sections 39600, 39601, 39667, 43013, 43018 and 431017(b), Health and 

Safety Code. Reference: Sections 39002, 39003, 39017, 39500, 39650, 39667, 40000, 43000, 

43000.5, 43013, 43018, 43701(b), 43801 and 43806, Health and Safety Code; and sections 233 and 

28114, Vehicle Code. 

Amend section 2023.4(b) to read as follows: 

§ 2023.4 Reporting Requirements for Transit Agencies. 

(a) [No Change] 

(b) The following reports on new urban bus purchases and/or leases by transit 

agencies on the diesel path shall be submitted as described below: 

(1) [No Change] 

(2) [No Change] 

(3) [No Change] 

(4) As set forth in section 2023.1(a)(5), transit agencies with more than 30 

buses in their fleet that purchase model-years 2007 through 2009 urban 

buses not certified at or below 0.2 g/bhp-hr NOx emissions shall submit

the following information for each urban bus purchased: the manufacturer, 

make, and model year of the engine of the urban bus or transit fleet 

vehicle retrofitted and for each diesel emission control strategy applied, 

the date of installation, the device’s product serial number, and its Diesel 

Emission Control Strategy Family Name in accordance with the 

requirements of section 2705(g)(2), title 13, CCR. The first report shall be 

submitted by January 31, 2007. Subsequent reports shall be submitted 

annually by January 31 through the year 2016.

* * * * * 

NOTE: Authority cited: Sections 39600, 39601, 39667, 43013, 43018 and 43701(b), Health and Safety 

Code. Reference: Sections 39002, 39003, 39017, 39500, 39650, 39667, 40000, 43000, 43000.5, 

43013, 43018, 43701(b), 43801 and 43806, Health and Safety Code; and sections 233 and 28114, 

Vehicle Code.