Driving in Iran is an ADVENTURE!! I didn't actually drive while there, Amir did that.  He was pretty good too. I was not afraid to drive, I did learn overseas after all, but I can't speak Farsi.  So how would I talk my way out of a ticket?  Or jail?  How does one flirt in a headscarf anyway?  Also, it wasn't my car and I was afraid I would be a little too aggressive. (It was Mohsen's fancy new car we were driving.) Yes, Iranians drive on the right side of the road.

The freeways, or autobahns (yeah, German) are OK   The signs are in Farsi and English, so they're not hard to figure out. Exits can be either to your left or right, so watch for the arrows.  Just remember that lane demarcations are merely suggestions.  Seriously.  The only time drivers stay in one lane is when one car passes another.  During the day you honk to signal you want to pass, at night you flash your brights.  Its a good system.

Be careful of trucks.  Good advice in ANY country. But if you get lost, truck drivers know where everything is.  Which is good to know since once you get off the autobahn and into the cities, there are NO signs.  Well, maybe a few street signs, but good luck seeing them at the same time you're avoiding a collision.
I saw a few traffic lights in bigger cities, but mostly they have roundabouts.  Now, if you are unfamiliar with this system or familiar only from Europe...HA HA!  Good luck.  You pretty much just go.  Don't hesitate.  Don't crash.  Just go.  The right-of-way is to he or she with the most chutzpah. (See video)

They also have speed bumps in random places.  And they aren't necessarily marked.  So you can be driving down the main streets of a town and BUMP.  On two lane highways between towns, just assume you're going to hit the bumps right in the middle of town.  Amir says its to slow people down.  I say its to stimulate the auto mechanic industry.
Parking is another stimulating experience.  You don't just park next to the sidewalk or the side of the road.   You can park two or three cars deep.  And just stop wherever you want.  (The Tuyserkan video shows this parking phenomenon.)   No really.  Just stop and get out.  And this doesn't just apply to parking.  I saw a guy get out of his car in the middle of the road to see why the traffic had stopped.  (it was one of the rare traffic lights)  I think he just couldn't believe people had actually stopped for a red light.  Ha Ha!

On the way to the airport we  got into a traffic jam and Mohsen got out to see what was happening.  He just walked forward and got news from the other drivers (who had walked forward to get it from the cops and by-standers).  I personally think this is fabulous.  Then people know what's going on and no one gets too upset because everyone knows what's happening.  And when the road was cleared everyone ran back and got into their cars.
Tehran is of course famous for traffic   And like in other countries I have lived, there are merchants who peddle their wares in the middle of the freeways.  A captured audience makes for great marketing prospects.  Lots of food vendors of course...I'm trying to think if I saw non-food items for sale...sunglasses maybe?  Hey some people see traffic as an annoyance, some as a business opportunity.  Capitalism at it's finest!