【Two Couples Affair in Broad Daylight】

Where Tesla's prototype electric Semi -- a battery-powered long-haul truck -- will go next is Two Couples Affair in Broad Daylightanyone's guess. But in recent days, Elon Musk's truck was spotted in Salt Lake City, Utah.

A woman who said she's a Tesla employee posted on her Instagram Friday pictures of the truck and an inside view of the big-rig. She wrote that it was only at the service center for an hour and "they wouldn’t tell us where it was going after this."

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Electrek has been tracking the vehicle as it winds its way through the U.S. Previous sightings in recent weeks have included Colorado, Illinois, Arkansas, and Iowa. The trip appears to be a way to show off the electric truck's range and cross-country capabilities. The truck is based in Nevada but it's clearly testing out routes farther and farther away from its home base.

We reached out to Tesla for more information on this mysterious road trip. Tesla's website says the Semi can go from 0 to 60 mph in 20 seconds and has a range of 300 miles. The expected base price is $150,000.

Also, this week Walmart upped its order of the electric trucks for its fleet. An additional 30 trucks were ordered to join others operating in Canada for a new distribution center opening in 2022, according to Electrek.

The truck is supposed to start production in 2019.