To amend the Internal Revenue Code of 1986 to allow a credit for the purchase of idling reduction systems for diesel-powered on-highway vehicles.

SECTION 1. SHORT TITLE.

    This Act may be cited as the ``Idling Reduction Tax Credit Act of 
2004''.

SEC. 2. IDLING REDUCTION TAX CREDIT.

    (a) In General.--Subpart D of part IV of subchapter A of chapter 1 
of the Internal Revenue Code of 1986 (relating to business-related 
credits) is amended by adding at the end the following new section:

``SEC. 45G. IDLING REDUCTION CREDIT.

    ``(a) General Rule.--For purposes of section 38, the idling 
reduction tax credit determined under this section for the taxable year 
is an amount equal to 50 percent of the amount paid or incurred for 
each qualifying idling reduction device placed in service by the 
taxpayer during the taxable year.
    ``(b) Limitation.--The maximum amount allowed as a credit under 
subsection (a) shall not exceed $3,500 per device.
    ``(c) Definitions.--For purposes of subsection (a)--
            ``(1) Qualifying idling reduction device.--The term 
        `qualifying idling reduction device' means any device or system 
        of devices that--
                    ``(A) is installed on a heavy-duty diesel-powered 
                on-highway vehicle,
                    ``(B) is designed to provide to such vehicle those 
                services (such as heat, air conditioning, or 
                electricity) that would otherwise require the operation 
                of the main drive engine while the vehicle is 
                temporarily parked or remains stationary,
                    ``(C) the original use of which commences with the 
                taxpayer,
                    ``(D) is acquired for use by the taxpayer and not 
                for resale, and
                    ``(E) is certified by the Secretary of Energy, in 
                consultation with the Administrator of the 
                Environmental Protection Agency and the Secretary of 
                Transportation, to reduce long-duration idling of such 
                vehicle at a motor vehicle rest stop or other location 
                where such vehicles are temporarily parked or remain 
                stationary.
            ``(2) Heavy-duty diesel-powered on-highway vehicle.--The 
        term `heavy-duty diesel-powered on-highway vehicle' means any 
        vehicle, machine, tractor, trailer, or semi-trailer propelled 
        or drawn by mechanical power and used upon the highways in the 
        transportation of passengers or property, or any combination 
        thereof determined by the Federal Highway Administration.
            ``(3) Long-duration idling.--The term `long-duration 
        idling' means the operation of a main drive engine, for a 
        period greater than 15 consecutive minutes, where the main 
        drive engine is not engaged in gear. Such term does not apply 
        to routine stoppages associated with traffic movement or 
        congestion.
    ``(d) No Double Benefit.--For purposes of this section--
            ``(1) Reduction in basis.--if a credit is determined under 
        this section with respect to any property by reason of 
        expenditures described in subsection (a), the basis of such 
        property shall be reduced by the amount of the credit so 
        determined.
            ``(2) Other deductions and credits.--No deduction or credit 
        shall be allowed under any other provision of this chapter with 
        respect to the amount of the credit determined under this 
        section.
    ``(e) Election not to Claim Credit.--This section shall not apply 
to a taxpayer for any taxable year if such taxpayer elects to have this 
section not apply for such taxable year.''.
    (b) Credit to Be Part of General Business Credit.--Subsection (b) 
of section 38 of such Code (relating to general business credit) is 
amended by striking ``plus'' at the end of paragraph (14), by striking 
the period at the end of paragraph (15) and inserting ``, plus'' , and 
by adding at the end the following new paragraph:
            ``(16) the idling reduction tax credit determined under 
        section 45G(a).''.
    (c) Conforming Amendments.--
            (1) The table of sections for subpart D of part IV of 
        subchapter A of chapter 1 of such Code is amended by inserting 
        after the item relating to section 45F the following new item:

``Sec. 45G. Idling reduction credit.''.
            (2) Section 1016(a) of such Code is amended by striking 
        ``and'' at the end of paragraph (27), by striking the period at 
        the end of paragraph (28) and inserting ``, and'', and by 
        adding at the end the following:
            ``(29) in the case of a facility with respect to which a 
        credit was allowed under section 45G, to the extent provided in 
        section 45G(d)(A).''.
    (d) Effective Date.--The amendments made by this section shall 
apply to taxable years beginning after December 31, 2003.

SEC. 3. DETERMINATION OF CERTIFICATION STANDARDS BY SECRETARY OF ENERGY 
              FOR CERTIFYING IDLING REDUCTION DEVICES.

    Not later than 6 months after the date of the enactment of this Act 
and in order to reduce air pollution and fuel consumption, the 
Secretary of Energy, in consultation with the Administrator of the 
Environmental Protection Agency and the Secretary of Transportation, 
shall publish the standards under which the Secretary, in consultation 
with the Administrator of the Environmental Protection Agency and the 
Secretary of Transportation, will, for purposes of section 45G of the 
Internal Revenue Code of 1986 (as added by section 2 of this Act), 
certify the idling reduction devices which will reduce long-duration 
idling of vehicles at motor vehicle rest stops or other locations where 
such vehicles are temporarily parked or remain stationary in order to 
reduce air pollution and fuel consumption.

Summary: Idling Reduction Tax Credit Act of 2004 - Amends the Internal Revenue Code to allow a business tax credit for 50 percent of the cost of a qualifying idling reduction device, up to $3,500. Defines "qualifying idling reduction device" as any device that is: (1) installed on a heavy-duty diesel-powered on-highway vehicle to provide services that would otherwise require the operation of the main drive engine while the vehicle is temporarily parked or stationary; and (2) certified by the Secretary of Energy to reduce long-duration idling. Directs the Secretary to publish standards for certifying such devices.