I've had a similar sentiment.
Cars are not enough like horses. They both eat fuel and exhale CO2. It is not for exhaling CO2 that a vehicle causes pollution. If it is, then we might as well shoot the animals and ourselves for being daily polluters; an idea some have essentially embraced. It is for NOT evaporating enough H2O. Cars pollute not because they emit CO2, but because they do not evaporate enough H2O to cool and serve the planet. With evaporative cooling the vehicle can be made more efficient, but with the corresponding increase in complexity and energy to serve out H2O at gas stations. With evaporative cooling there is less energy required to cool the engine. Even adding water to the combustion is proven to increase mileage. Water is a required carrier of entropy off the planet, and if we don't evaporate water off the hot body where the energy is consumed, then it has to be evaporated somewhere else. A hot body like an engine will evaporate water even where there is a very high humidity.
As water is evaporated, it is better than a solar collector... without putting solar cells on top of a vehicle, every vehicle can be turned into a solar collector. After evaporation the sun takes the water from there... the water will absorb infrared sunlight in the day and be driven higher in the atmosphere. As the H2O condenses and forms a cloud, it releases infra-red above the atmosphere, not below it. Right now the car releases entropy below it, and demands the rest of nature to make up for it. In the night when conditions are good for water to condense, it also releases infra-red at an opportune time. Hot air by itself does not get rid of entropy in the same manner because the molecules are not little electrical dipoles. That is why the car needs to evaporate H2O, because for all the light that arrives to the planet, light must leave the planet or things will warm up. The goal is to get the entropy off the planet. Rain also filters and cleans, and it would be nice to have the electricity from hydro but to keep the rivers too. The car that evaporates water also helps capture energy.
A person might ask how there is not enough evaporation when most of the surface area of the planet is ocean. The trees have had far greater surface area than the ocean. They too have been trimmed. In terms of capturing solar energy, the air-water interface of the ocean is not exactly efficient for evaporating water. Over land is better at evaporating water. Evaporative cooling does not necessarily have to be clean potable water either... I can easily imagine designs that use dirty water with some sort of reverse osmosis, but then our vehicles will have to pee when they get to the gas station. You can take a horse to a gas station, but you can't make it pee there. Perhaps cars and horses will never be entirely alike, but lets make them a step closer.
}
