The Legislature and Gov. Scott Walker just proposed taxing hybrid and electric vehicles in Wisconsin to raise more money for roads — essentially penalizing progress in cleaner automobile technology.

They argue that by charging $100 per fuel-efficient vehicle, the state could raise about $8 million for roads. That’s actually a small amount of money in the scope of the budget deficit for transportation needs.

The narrow-mindedness of such a policy completely ignores the harmful effect that tailpipe exhaust from gasoline and diesel vehicles has on our citizens. The cost includes illness, death and financial losses that will be far larger than the higher revenue the Legislature hopes to bring in. It might be smarter economically — and better for Wisconsinites — to tax the more polluting cars and trucks.

According to a study by the Electric Power Research Institute, electrification of our vehicle fleet would improve air quality, especially if the source of electricity used to meet new demand does not come from coal-fired power plants. The benefits of electric vehicles must be inherently viewed as coupled to their power source.

Coal-fired power plants emit particulate matter, mercury and other hazardous pollutants. Natural gas plants are very much cleaner than coal and oil, but still emit a small amount of nitrogen oxides. Electricity powered by wind, solar and hydroelectric, of course, maximizes the air quality and health dividends from electric cars.

But even if electric power continues to include some dirty coal plants for a few more years, electric and plug-in electric hybrids tend to be better for our health. A major study across 17 industrial areas showed that reductions in particulate matter and nitrogen oxide emissions from mobile sources yield greater air quality (and subsequent health) benefits than the same reduction from electricity-generating power plants.

Another comparison is air pollution with vehicle miles traveled. We studied the health implications of reducing 20 percent of vehicle miles traveled in the 11 largest cities in the Great Lakes region. The resulting improvement in air quality would reduce the number of asthma cases by 2,500, heart attacks by 860, and deaths by 525 per year. Cost savings from avoided hospitalizations and deaths would be about $4 billion. Milwaukee and Madison were part of this 11-city study, and the savings just for these two Wisconsin cities was about $105 million annually.

So which policy makes more sense (and “cents”)? Taxing hybrid and electric vehicles to raise $8 million? Or promoting fuel efficiency and saving $105 million? If decision makers choose the first option and tax cleaner vehicles, that’s a huge financial mistake. But that choice also signifies much more. It would represent a moral transgression, sacrificing the health of Wisconsin citizens to raise small funds for roads. It also would signal a strange desire to go backward in transportation technology.

Clearly, we need to find a different financial model to support roads — especially one that incentivizes clean and healthy transportation.

Patz is director of the Global Health Institute at UW-Madison.