Welcome to the law of unintended consequences. The math is simple although one doubts Congress bothered. When you replace gas guzzlers with more efficient vehicles you reduce gas consumption which reduces the amount of gas tax money going into the six year highway trust fund.
The $920 million estimated here is actually chump change compared to the hit the trust fund will take in a few years when hybrids and electric cars become common place. Congress hasn’t had the courage to raise the gas tax in two decades. What do you think they’re going to do when receipts are cut by 25 or 30 percent?
