There seems to be several ways to ensure that the brake, turn signal and tail lights all work from the tow vehicle.
I guess the question would be what is the best way? I have everything I need to connect to the existing wiring including diodes to prevent sending voltage back in the wiring to things that don't work well when that happens. But, here's the issue, everything kit available is based on standard 14awg wiring.
The Smart Car is no where near 14, it seems to be somewhere around 20awg or so.
I also have looked into alternative choice for tail lights as in detachable. But, the Smart car is plastic so forget magnetic and I have yet to find suction cup types of removable lights.
There was a thread on either this forum or www.smartcarofamerica.com where a member posted about using REMOTE & WIRELESS taillights that screwed into the rear tow-bolt holes on the smart?
Can't seem to find it at the moment, but you might try searching that out?