; and (C) any single unit truck— (i) the bottom of the carriage of which is greater than 22 inches above the ground; (ii) with a gross vehicle weight rating of 10,000 pounds or more; and (iii) that is manufactured on or after the effective date of the rule. (2) Retrofit requirements Not later than 3 years after the date of enactment of this section, the Secretary shall issue a rule requiring the installation of front underride guards on— (A) any trailer with a gross vehicle weight rating of 10,000 pounds or more that is manufactured before the effective date of the rule under paragraph (1); (B) any semi-trailer with a gross vehicle weight rating of 10,000 pounds or more that is manufactured before the effective date of the rule under paragraph (1); and (C) any single unit truck— (i) the bottom of the carriage of which is greater than 22 inches above the ground; (ii) with a gross vehicle weight rating of 10,000 pounds or more; and (iii) that is manufactured before the effective date of the rule under paragraph (1). (3) 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 (2) shall be required beginning on the date that is 1 year after the respective issuance date of each rule. (B) Phase-in The Secretary may permit a phase-in period (not to exceed 3 years) for the installation of front underride guards on vehicles described in paragraph (2). (4) Report Not later than 1 year after the date of enactment of this section, the Secretary shall— (A) complete research on equipping the vehicles described in paragraphs (1) and (2) with a front underride guard to prevent trucks from overriding the passenger vehicle