Critics of expanding commuter rail service in Northwest Indiana are fond of pointing out — correctly — that the South Shore cannot operate without a subsidy. While it’s true that commuter rail service requires a subsidy, so do other forms of transportation — including highways.

A new report by Subsidyscope drives home that point.

Using Federal Highway Administration statistics, Subsidyscope fround that in 2007, just 51 percent of the money set aside for highway construction and maintenance — $193 billion nationwide — was generated through user fees.

Yes, that means only half of the cost of highway construction and maintenance is generated through user fees. Interestingly, that’s close to the same split for the South Shore Railroad — about half from fares and half from government subsidies.