; and (B) submit to the Committee on Commerce, Science, and Transportation of the Senate and the Committees on Transportation and Infrastructure and Energy and Commerce of the House of Representatives a report on the research described in subparagraph (A). (3) Retrofit requirements Not later than 3 years after the date of the enactment of this section, the Secretary shall issue a rule requiring all commercial motor vehicles with a gross vehicle weight rating of more than 10,000 pounds to be equipped with a front underride guard. (4) Compliance dates (A) In general Except as provided in subparagraph (B), compliance with each of the rules issued by the Secretary under paragraphs (1) and (3) shall be required beginning on the date that is 1 year after the respective issuance date of each such rule. (B) Phase-in The Secretary may permit a phase-in period (not to exceed 3 years) pursuant to paragraph (3) for the installation of front underride guards on commercial motor vehicles. (d) Maintenance requirements (1) Revised standard (A) In general The Secretary shall require that the underride guard required under this section be maintained in safe and proper operating condition to maximize its effectiveness in saving lives. (B) Periodic inspections The Secretary shall require periodic inspections of the comprehensive underride protection system in trailers, semi-trailers, and single unit trucks to ensure that the guards are in safe and proper operating condition, including identification of any rust, corrosion, cracked welds, cracked or fractured vertical members, cuts, or tears in any underride guard to ensure the integrity of the guard. (C) Effect of inspection results (i) Passing In carrying out subparagraph (B), the Secretary shall— (I) authorize motor vehicles that pass the inspection described in subparagraph (B) to display a Commercial Vehicle Safety Alliance Inspection Decal, which shall be valid for 3 months