Grooves in the truck bed?

vehicle development/design

1 - Concept (show car) [Tesla avoids]
2 - Prototype
3 - Engineering Prototype ~10 [work out specific details for parts and sub-systems and materials]
4 - Validation Prototypes ~10 [work out production methods and do certification for government requirements and endurance]
These cars could actually be sold if assigned a VIN# - BUT they are often worn out - very high mileage use
5 - Start selling

So far only the Prototype(s?) has been built, as far as we know. So we can imagine many details are being worked out.

Also consider Tesla seems unique with continuous improvement (not just over the air updates).
You can verify at Teslatap.com - (2019 much improved over the 2012 Model S)

 

From other angles I’ve observed on videos and still photos, those black stripes might be inlaid rubber strips to keep the sliding around of cargo to a minimum. Just a guess, this point.

 

I believe there are T-slots. Design to hold any of the many T connectors. Some T-connectors have tie-down hooks, some hold struts for racks, others allow slide in slide out assembled structures like stoves, camping tents, etc. With these slots it would be easy for anyone to build things like a pipe rack, bicycle racks, sleeping space, etc. in the bed, and make them easy to change-out.

 

No really. If you look at the pictures with tailgate down, the slots run all the way to end of the bed. If you blew air or power-washed the bed everything would shoot out.

 

hahaha. I thought by title you meant in the back with the lady ......