The Subsidy Allocation Model (SAM) is Northern Virginia’s regional mechanism for the allocation of funding for public transportation, established by NVTC resolution and codified in Virginia law. SAM allocates state transit assistance and regional gas tax revenues collected by NVTC, estimated at $340 million in FY2026, to its member jurisdictions.
The model recognizes the interconnected nature of the region’s transit systems, where investments in one system can impact transit throughout the region. The SAM formula and hold harmless provisions ensure that local and regional priorities are balanced, helping to preserve transit service across Northern Virginia.
The data inputs of the SAM formula include the following budgeted amounts for each NVTC jurisdiction:
- WMATA operating subsidies, including debt service
- WMATA capital subsidies
- Local operating deficits, excluding Loudoun County
- Local capital needs, excluding Loudoun County
Those inputs are totaled for each jurisdiction, with the local capital needs amortized over a 5-year period. Each jurisdiction’s total is compared to the NVTC-wide total to calculate a percentage share. The percentages are applied to the total DRPT transit operating and capital assistance reimbursements received during the fiscal year.
Regional gas tax revenue is allocated based on the prior year’s collections on a point of sale basis for the initial NVTC WMATA compact members. Each jurisdiction’s percentage share of the NVTC total is used to allocate the gas tax received during the fiscal year among those jurisdictions. The regional gas tax revenue for Loudoun County is allocated based on the current year actual point of sale.
While presently no WMATA formula apportioned jurisdiction debt service, the SAM formula specifies that 95% of WMATA debt service is taken off the top from capital assistance reimbursements as those funds are received. The remaining 5% is deducted from the motor fuels tax revenues. These funds are required to be withheld and remitted directly to WMATA by NVTC.
Revenue is taken off the top of the state assistance before allocating among the jurisdictions for certain expenses. These include a portion of NVTC’s General and Administrative budget, as reflected in the annual approved budget, and the NTD bus data collection.
The SAM formula includes several hold harmless mechanisms as described in the “summary of the resolution #756…” document.
Allocated revenue is held in trust for each jurisdiction for their restricted use for transit purposes. Disbursements are made by written request by the jurisdiction, and may include payments to WMATA as well as support for local operating and capital transit needs.
