• The Greater Philadelphia Diesel Difference supports the implementation of EPA and CARB verified clean diesel retrofit technologies on diesel powered engines, but does not endorse any specific brand-named clean diesel technology.


  • Unless otherwise authorized by the Executive Committee, no one can represent himself or herself on behalf of the Diesel Difference.
  • Unless qualified under one of the programs implemented by the Diesel Difference, no one may use their affiliation with the Diesel Difference as an endorsement of their product by the Diesel Difference.
  • No clean diesel technology vendor may improperly solicit Working Group members, as defined inappropriate by the Executive Committee of the Diesel Difference Working Group.


  • The Philadelphia Diesel Difference Logo ("Logo") is a valuable asset and as such must be properly used and protected. To ensure appropriate use of the Logo, the Philadelphia Diesel Difference ("PDD") sets forth the following guidelines for conditions under which members can use the Logo. The guidelines apply to all PDD members, their employees, business partners, advertising agencies, and all other affiliates and other third parties. The PDD reserves the right to modify these guidelines as deemed necessary:

    a) Members shall obtain written permission from the PDD Project Coordinator prior to use of the logo. All requests shall be submitted in writing, detailing the member's intended use;

    b) The Logo shall be used only in a manner consistent with the PDD initiatives set forth in the Organizational Structure and approved by the PDD Project Coordinator;

    c) The Logo may not be associated with engines, vehicles or fleets that do not qualify for recognition through the PDD recognition program, except as determined by the Executive Committee. However, any vehicle using a device or fuel verified as a diesel emissions reduction technology by the Environmental Protection Agency or the California Air Resources Board may display the logo. PDD will provide decals to all fleets honored through the Diesel Difference recognition program. In addition, the Executive Committee may authorize logo use by fleets implementing: auxiliary power units, diesel hybrids, truck stop electrification and closed crankcase technologies. The Executive Committee may add new technologies to this list at its discretion.

    d) In order to preserve the accuracy and quality of presentation of the Logo, any alteration of the Logo is strictly prohibited;

    e) The PDD, at its sole discretion, reserves the right to withdraw a member's right to use the Logo at any time and for any reason.

    f) The logo cannot be used for sale of merchandise unless expressly in writing from the board (or whatever designate) e.g., Shall not be used for:

    (1) the promotion or sale of or in any other connection with any
    goods whatsoever;

    (2) the encouragement directly or indirectly of support including
    donations or otherwise for other charitable or similar purposes; or

    (3) the promotion or sale of or in any other connection with any

    g) The logo may not be revised or altered in any way and must be displayed in the same form and color.

    h) The logo may not be used in any manner that, in the sole discretion of
    DD: discredits DD or tarnishes its reputation and goodwill; is false or misleading; violates the rights of others; violates any law, regulation or other public policy; or mischaracterizes the relationship between DD and the user, including but not limited to any use of the logo that might be reasonably construed as an endorsement, approval, sponsorship, or certification by DD of the user, the user's business or organization, or the user's products or services, or that might be reasonably construed as support or encouragement to purchase or utilize the user's products or services unless expressly authorized in writing