It's long been expected that sooner or later, the Tesla Model S electric sport sedan will be offered with all-wheel drive.
Now, two different Tesla fans have captured photos and video of what appears to be a prototype test vehicle with external instrumentation driving around the San Francisco Bay Area.
As published on TransportEvolved, the video and first photos posted yesterday by Frank Hsueh--which aren't of particularly high quality--simply showed the silver Model S with roof-mounted instrumentation and wheel sensors on all four wheels.
MORE: AWD Tesla Model S Coming Soon? (Warning: Pure Speculation) -- April 2013
But then a closer and much crisper shot appeared, and it seems the test car rides slightly higher than a standard Model S.
Tesla Model S all-wheel-drive prototype testing in California, March 2014
It's fitted with California "manufacturer" license plates, and was photographed near an entrance to the University of California--Santa Cruz, about 40 miles from Tesla's Palo Alto headquarters in Silicon Valley.
Tesla CEO Elon Musk said in a Q-and-A session in Norway last month that all-wheel drive will appear as an option on the Model S, but not until the Model X is in production in early 2015.
Tesla's chief technical officer, JB Straubel, added that the AWD system in the Model S will be "an efficiency-neutral option." Which is to say, it won't reduce the car's rated electric range.
Subsequent comments to the TransportEvolved piece suggested that the odd roof rack on the test car adds enough weight to simulate the total vehicle weight of the Model X crossover utility vehicle, Tesla's second car.
That model is to be unveiled later this year and go into volume production early next year.
What do you think? Is this the long-awaited all-wheel-drive Tesla Model S being tested? Or some kind of autonomous version? Or something else entirely?
Leave us your thoughts in the Comments below.