How does $100 even compare? Currently in California there is a 79.6 cent tax(18.4 federal + 61.2 state) on a gallon of gasoline (I googled and it came up with a price of $3.36 per gallon. That boils down to a ~24% tax on gasoline. So for spending $416 dollars on gas, you'd be paying $100 of tax. I don't think paying $100 is even remotely enough to make up for the missing revenue.

Further, a fixed fee penalizes people that drive a lot exactly as much as people that barely drive whereas a tax on the consumed quantity, gas or electricity, takes into account how much a person is using the road infrastructure.