Transportation officials said they were concerned the drop would sap funding for the nation's highway system. "As driving decreases and vehicle fuel efficiency continues to improve, the long term viability of the Highway Trust Fund grows weaker ... The way we finance America's transportation network must also change to address this new reality, because banking on the gas tax is no longer a sustainable option." Federal Highway administrator Tom Madison said in a statement, "This underscores the need to change our policy so American infrastructure is less dependent on the amount of gas American drivers consume." Full Article at CNN/Money