Let’s talk about the American Solar Challenge. Or, to put it another way, let’s direct our attention to the Great Gas Station in the Sky.

Transportation requires energy. It’s one of the fundamental tenets of the Laws of Motion defined by Newton (not me, the other one). Until the advent of the combustion engine, vehicles were primarily powered by horses and oxen, which gained their energy by eating hay and the like.

Motor vehicles tend not to run on hay (though no doubt it’s been tried in idealistic communes in California). They thirst for fossil fuel, which is increasingly expensive and must be topped up regularly.

If only there were an abundant source of free energy we could tap into at will, enabling us to travel great distances for next to nothing. Where could we find such a thing? The answer is as clear as daylight. All we need to do is harness the energy of the sun.

The idea is simple; translating it into reality is not. What initially began as an intellectual race to develop the world’s first viable solar-powered car soon became a literal race. In 1985, the Tour de Sol took place in Switzerland, with 72 vehicles competing to go farthest and fastest.

The American version of the race was initiated in 1990, attracting entries from universities across the United States and beyond. The 2014 edition of the American Solar Challenge starts in Austin, Texas, July 21. Over the next eight days, the competing solar-powered cars will face a 1,700-mile journey to Minneapolis-St. Paul, tackling city streets and open highways.

For most of us, the closest we can currently get to a solarpowered car is as a spectator along the route of this event, or at similar races in Australia and South Africa. After 30 years of technological innovation, we are seemingly no closer to being able to buy for ourselves a mass-produced solar-powered vehicle.

The vehicles competing in the American Solar Challenge bear little relation to the average family sedan. They tend to be low and flat, covered in photovoltaic cells to extract maximum energy from the sunlight. The wheels are thin and hard to reduce rolling resistance, to the detriment of a smooth ride. The single occupant sits in a cramped cockpit.

In terms of design, the competing vehicles appear to be headed down a cul-de-sac. As the teams seek solutions for some of the fundamental handicaps of solar energy — not least, cloud cover and the night — they steadily move further away from the automotive mainstream.

And yet, if you are at the finish line in the Twin Cities on July 28, you won’t fail to be impressed by how far the vehicles have come, and how fast. At the event’s inception, the competitors struggled to reach 30 mph. Now they are capped at 65 mph, and could probably travel much faster. The potential reliable range has increased from hundreds to thousands of miles.

Technological innovations instigated by solar-powered racing may yet change the vehicles we drive. Monaco-based Venturi has already proposed a mass-produced solar vehicle (though it looks like a golf cart and only has three seats).

More significantly, Ford recently unveiled the C-MAX Solar Energi concept car, a hybrid vehicle with photovoltaic panels on the roof, capable of up to 108 miles to the gallon. Fuel efficiency is one thing, but the Ford also looks good.

The crucial test of a commercially viable solar vehicle is this: If you bought one, would it impress your neighbors? It’s the first principle of the Law of Auto Envy, as defined by Newton (not the other one, me).