If a conformity determination is not made according to the required frequency requirements, areas have a one-year grace period after the missed deadline before a conformity lapse applies. (This one-year grace period does not apply to newly designated nonattainment areas.) during the 12 month grace period, only transportation projects in the most recent conforming metropolitan transportation plan and TIP can be funded or approved. once an area is in a conformity lapse, the use of Federal transportation funds is restricted to certain kinds of projects and no new non-exempt projects can be amended into the metropolitan transportation plan/ TIP. These include "exempt projects" such as safety projects and certain mass transit projects, TCMs from an approved SIP, and project phases that were authorized by the FHWA/FTA prior to the lapse. The FHWA and FTA do not reduce the amount of funding a State receives if there is a lapse; however, use of Federal funds is restricted during the lapse.
Often, a lapse may occur due to a missed deadline such as an expired metropolitan transportation plan, TIP, or conformity determination. In this case, the lapse may be resolved by completing the necessary steps to fulfill transportation or air quality planning requirements. There are two options to resolving a conformity lapse if emissions estimates exceed the motor vehicle emissions budget: change the projects in the metropolitan transportation plan or TIP (either the mix or timing of projects), and/or revise the motor vehicle emissions budget. In order to revise a motor vehicle emissions budget, a SIP revision is required. Also, in order to revise a budget, the State air quality agency may need to identify additional control measures from on-road or other sources of pollution in order to increase the budget for on-road emissions.