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Construction Program Guide

Contract Time

The FHWA's policies for construction time and time extensions provide for their use and for the review and approval of time related contract modifications for Federal-aid participation.

Authority/Legal Basis

  • 23 U.S.C. 315 Rules, regulations, and recommendations (2012) provides very broad authority for the Secretary of Transportation to prescribe regulations to carry out the Federal-aid highway program. However, there are no specific statutes dealing with construction contract modifications other than the required use of standardized changed conditions clauses as required by 23 USC 112(e).
  • 23 CFR 635.102 Definitions (04/01/2013)
  • 23 CFR 635.109 Standardized changed condition clauses (04/01/2013) prescribes the standardized contract clauses mandated by the 1987 Surface Transportation and Uniform Relocation Assistance Act. These contract clauses include the following:
    • Differing Site Conditions,
    • Suspensions of work ordered by the engineer, and
    • Significant changes in the character of work

Subsection (c) address the unique use of changed condition clauses for design-build contracts. The FHWA encourages but does not require the use of such clauses in design-build contracts.

The above regulations provide the FHWA's regulatory policy regarding construction contract modifications. However, please note that these regulations were last updated on August 2, 1991 and do not include revised stewardship, oversight, and applicability requirements resulting from the 1991 ISTEA and the 1998 TEA-21. See the discussion in the FHWA Contract Administration Core Curriculum Manual for a summary of current FHWA policy).



General Information


Updated: 03/30/2023
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000