It’s worth noting that for over 50 years, the trust fund was fully self-sufficient with no general fund contributions. There’s been a shortfall in recent years

It’s worth noting that for over 50 years, the trust fund was fully self-sufficient with no general fund contributions. There’s been a shortfall in recent years because Congress is reluctant to increase the gas tax. As fleet fuel economy continues to increase, the tax revenue per mile driven continues to fall.