Regenerative braking is a standard and expected part of any electrified car now, from Honda's mild hybrids up through battery-electric vehicles like the Tesla Model S.
It lets the car recapture energy from momentum, which would otherwise be wasted as brake heat, by running the electric motor in reverse to recharge the battery.
But what was the first car to employ regenerative braking?
According to a short piece in Car Design News, it was an electric concept car called the Amitron, unveiled in 1967 by--of all things--American Motors.
Shorter than a Smart ForTwo minicar, it was sufficiently wide for three passengers to sit side by side.
The 1,100-pound car was powered by a combination of nickel-cadmium and lithium-nickel-fluoride batteries, the former for quick power delivery on acceleration, the latter for maximum energy storage for sustained cruising.
Together, the combined battery gave the Amitron a sustained range of 150 miles at a speed of 50 mph.
But it was also the very first car to use regenerative braking to recapture energy and recharge its battery on deceleration.
1976 AMC PacerEnlarge Photo
While the company had planned to offer the Amitron as a commuter vehicle within five years, it never did so, despite a second concept car in 1977 called the Electron that looked very similar.
The short-but-wide layout reappeared in the 1975 Pacer compact, however.
American Motors went on to be acquired by France's Renault in 1983, which then sold it to Chrysler in 1987, largely on the value of its Jeep brand.
Chrysler itself was bought by Daimler in 1998, then sold to a private equity firm in 2007, before collapsing in bankruptcy two years later during the economic recession.
With restructuring and financial aid from the U.S. government, Chrysler was effectively given to Italy's Fiat, which is now in the process of consolidating the two automakers.
CEO Sergio Marchionne famously carped that the Fiat 500e electric compliance car that Chrysler is forced to sell in California by that state's zero-emission vehicle rule costs the company $10,000 more than it makes for each one.
But still, perhaps, back there in some dusty company archive or little-noticed garage, the Amitron waits to reclaim its place in history?