Driving in Turkey?
 

I know some may consider this insane but I have driven in many countries and although it may not be a civilized as driving in the US I am always up for an adventure. We plan on renting a car on our last day in Istanbul and traveling down the coast and then up to Cappadocia. I would like to hear from other people who have driven there. Thanks!

Not insane at all! I drove through western Turkey last year and was amazed that so many people had described it as deathly dangerous. Here are some tips:
1. The few toll roads are not crowded at all and you can make excellent mileage. This can be a relief when you've spent several hours tiddling along behind some tractors.
2. Try not to drive at night. There are cars, tractors and bikes without lights, as well as people, donkeys and sheep.
3. Watch out for sudden potholes and speed bumps. Most roads in the west are in good shape, but be alert.
4. Navigation is fairly straightforward if you have a good map. Get one before you leave; the map I brought from the Netherlands was better than anything I found in Turkey.
5. Don't underestimate your distances. Without exception, every drive took me longer than I'd planned, and I ended up cutting short some of my time on the coast.
6. One of the surprise highlights was the town of Bursa. The mosques and zellige (mosaic tile) work were stunning and the town was a lively mix of conservative & hip. Near Bursa there are several cities famous for ceramics. (If you have a car you can buy things!)
7. Don't play chicken with taxis. Most of them have an evil eye hanging from the back bumper that seems to protect them from harm. You don't.
Enjoy your trip!

My friends just returned from a driving trip in Turkey and they found it no different than other mediterranean countries as far as the driving habits go. However, the gas was expensive, I believe she said $1.48/L.

Jenviolin has given you good advice and I will add to it the following

Make sure you have insurance through your credit card (check before you leave and make sure Turkey is covered) or purchased through the agency. We got a flat tire (first ever with a rental car) and got sideswiped by a bus (minor paint damage). You will notice a lot of cars with windshield damage so I was glad to have the additional windshield/tire/etc insurance.

Get a good map that has road grades and elevations. Driving through the mountain areas was very stressful and of course added to the time.

If at all possible avoid driving in big cities.

I like your sense of adventure. Though we were on a tour (the only one I've ever taken specifically because the distances were so great in Turkey) I did notice that most roads were in good condition and the signage was pretty good and in English.

Do have an idea where gas stations are located and have an emergency number. If at all possible, suggest you rent a cellphone for the time you'll be driving, in case you get lost or you'll be late arriving at your hotel. You just never know, and hopefully, you'll never need to use it.

We did, however, see quite a number of accidents, mostly from small cars trying to get around slow moving farming vehicles - terrible.

Besides having a good map, know how far/long you want to drive in any given day and how much time touring along your route and plan on where you will be sleeping at night. You'll find that once you're out in the country, away from city populace, you're limited on decent places to sleep and where you can eat. Sure there are local restaurants, but often there are great distances between what you'll find. And know that you're likely to only find "squat toilets" on the road - so be prepared.

If once you leave the area around the Med (in Antalya) and start heading towards Cappadocia you've got a long trip ahead of you. Midway is Konya which is a good stop, but the road from there is desolate.

And don't be tempted because the roads are empty to put your foot down on the gas - you never know where a vehicle will come from and roads can be tricky at dusk.