Wind-tunnel testing has proven that the Lightyear 0 is the most aerodynamic production car in the world, Lightyear claims.

Testing conducted at the FKFS wind tunnels in Stuttgart, Germany, under WLTP protocols confirmed a 0.175 coefficient of drag (Cd) for the solar-assisted electric car, Lightyear said Thursday in a press release.

That figure puts the Lightyear 0 ahead of the Lucid Air, Tesla Model S, and Mercedes-Benz EQS, all at 0.20 to 0.21. Each of those are much larger than the Lightyear 0, however, and will likely be produced in higher volumes. Lightyear has said it only plans to sell 150 cars (priced at about $260,000 each), with a "high-volume" model to follow.

Lightyear 0

Lightyear 0

Lightyear's claim is an impressive achievement for even a low-volume production car, however.

The Mercedes EQXX achieves just 0.17, but it's not production-bound. The concept is a showcase of ideas to improve EV efficiency, and did a real-world range run of 746 miles from Stuttgart to Silverstone, England, on a single charge—with enough energy to spare for some victory laps.

Launched in 2013, the Volkswagen XL1 achieved a 0.189 Cd. The slim coupe used a plug-in hybrid diesel powertrain that seemed like a good idea in the days before the VW emissions scandal, and was actually produced in very limited numbers. Just 200 were sold out of a planned run of 250 cars exclusively for the European market, where the Lightyear 0 will also be available.

Lightyear 0

Lightyear 0

The production General Motors EV1 had a Cd of 0.195, but that was achieved with a fairly impractical two-door body shell. The EV1 wasn't a high-volume car, either. GM built 1,117 and leased them to customers in California and a handful of other locations. Most were recalled and destroyed after California changed its zero-emission vehicle laws, allowing the EV1 to be withdrawn without the threat of penalties.

The EV1, XL1, EQXX, and now the Lightyear 0 have shown that cutting drag requires a radically different shape to conventional cars. Does that make sedans obsolete? At the very least, designers and engineers attempting to make a three-box sedan with leading-edge aero face some tough challenges.