	Introduction

The Trump Administration requested $75.1 billion for the Department of Transportation (DOT) for FY2018, 2.6% ($2 billion) less than DOT received in FY2017. On July 21, 2017, the House Committee on Appropriations reported H.R. 3353 . The committee recommended $77.5 billion for DOT, a 0.5% ($430 million) increase over the comparable FY2017 amount and 3% ($2.4 billion) above the Administration request. On July 27, 2017, the Senate Committee on Appropriations reported S. 1655 . It recommended a total of $78.6 billion in new budget authority for DOT for FY2018 ($78.5 billion after scorekeeping adjustments), 2% ($1.6 billion) above the comparable FY2017 amount and 4.7% ($3.5 billion) over the Administration request. Conflicts over funding levels and spending limits for federal agencies delayed action on final FY2018 appropriations until March 2018. Until that time, a series of continuing resolutions provided temporary funding for federal agencies. Finally, after passing legislation raising the spending limits for federal agencies for FY2018, Congress passed an omnibus spending bill, P.L. 115-141 , which included increased spending for most agencies. Title I of Division L, the DOT Appropriations Act, provided $86.2 billion, 11.8% ($9.1 billion) more than in FY2017. Two large trust funds, the Highway Trust Fund and the Airport and Airway Trust Fund, have typically provided around 90% of DOT's annual funding in recent years (92% in FY2017), but in FY2018 a significant increase in discretionary budget authority resulted in the proportion drawn from trust funds dropping to 83%, despite the actual amount increasing by $1 billion; see Table 2 . One reason for the shortfall in the fund is that the federal gas tax has not been raised since 1993. The Senate bill also recommended that the portion of funding allocated to projects in rural areas be increased from 20% to 30%; the same change was included in the Senate-passed DOT appropriations bills in FY2016 and FY2017, but was not enacted. Congress has continued to support the TIGER program through annual DOT appropriations. As Table 5 illustrates, the TIGER grant appropriation process has followed a pattern for several years, with the Obama Administration requesting as much as or more than Congress had previously provided; the House zeroing out the program or proposing a large cut; the Senate proposing an amount similar to the previous appropriation; and Congress agreeing on a final enacted amount similar to the previously enacted amount. Additional Infrastructure Funding

The FY2018 enacted legislation included significant increases in funding for infrastructure for aviation, highways, passenger rail, and transit, in some cases beyond the authorized levels, in other cases provided in newly created accounts. The Trump Administration's FY2018 budget request did not include any funding for the cost of PTC implementation, nor did the House or Senate Appropriations Committees recommend any funding for this purpose. They contend that the higher federal share makes highway projects relatively more attractive than public transportation projects for communities considering how to address transportation problems. Since the new tunnel would carry both intercity and commuter rail traffic, it is eligible for DOT funding from both the intercity rail program and the public transportation Capital Investment Grants program.
Congress appropriated $86.2 billion for the Department of Transportation (DOT) for FY2018. This represented a $9.1 billion (11.8%) increase over the amount provided in FY2017. The principal reason for the higher spending level was increases in funding from the general fund for highways, public transportation capital investments, and passenger rail projects. The appropriation was included in an omnibus spending bill, P.L. 115-141, Title I of Division L, the DOT Appropriations Act.
The DOT appropriations bill funds federal programs covering aviation, highways and highway safety, public transit, intercity rail, maritime safety, pipelines, and related activities. Federal highway, transit, and rail programs were reauthorized in fall 2015, and their future funding authorizations were somewhat increased.
The Trump Administration proposed a $75 billion budget for DOT for FY2018, including $16.4 billion in discretionary funding and $58.7 billion in mandatory funding. That was approximately $2 billion less than was provided for FY2017. The budget request reflected the Administration's call for significant cuts in funding for transit and rail programs.
The annual appropriations for DOT are combined with those for the Department of Housing and Urban Development (HUD) in the Transportation, Housing and Urban Development, and Related Agencies (THUD) appropriations bill. The House Appropriations Committee reported H.R. 3353, the THUD FY2018 appropriations bill, in which Division A provided FY2018 appropriations for DOT. The committee recommended $77.5 billion in new budget authority for DOT, 0.5% ($400 million) more than ultimately approved for FY2017 and roughly 3% ($2.4 billion) more than the Administration requested.
The Senate Appropriations Committee reported out an FY2018 THUD bill, S. 1655, which was not taken up by the full Senate. The Senate committee recommended $78.6 billion in new budget authority, 2% ($1.6 billion) more than the comparable FY2017 amount and 4.7% ($3.5 billion) more than the Administration requested.
Conflicts over funding levels and limits delayed action on final FY2018 appropriations until March 2018. Until that time, a series of continuing resolutions provided temporary funding for federal agencies.
There is general agreement that more funding is needed for transportation infrastructure, and the Trump Administration has proposed an increase in spending on infrastructure, but Congress has not been able to agree on a source that could provide the additional funding. The federal excise tax on motor fuel, which is the primary funding source for federal highway and transit programs, has not been increased in over 20 years, and does not raise enough revenue to support even the current level of spending. To address this shortfall, Congress has transferred money from the general fund to the Highway Trust Fund on several occasions since 2008 to provide sufficient funding for the programs. Revenue estimates by the Congressional Budget Office (CBO) suggest that general fund transfers will continue to be required in future years to support the currently authorized level of highway and public transportation spending.