Who is subsidizing who?

From "Whose Roads? Defining Bicyclists' and Pedestrians' Right to Use Public Roadways" by the Vicoria Transport Policy Institute; 2004

"Pedestrians and cyclists pay more than their fair share of roadway costs. Although most highway expenses are funded through motor vehicle user fees, local roads and traffic services are funded primarily through general taxes that residents pay regardless of their travel habits. Motor vehicle use also imposes a variety of external costs, including parking subsidies, congestion, uncompensated crash damages, and environmental impacts. Pedestrians and cyclists impose much less external costs, due to lower costs per mile, and because they tend to travel fewer miles per year. In general, people who drive less than average overpay their true share of transportation costs, while those who drive more than average underpay. As a result, pedestrians and bicyclists tend to subsidize motorists."