Can anyone tell me the legal requirements regarding children travelling in cars in Turkey?
For instance, when we come in May, does our 4 year old need a child seat?

well.. here is something US embassy has to say on the subject

DEFENSIVE MEASURES

*Always wear seat belts. They can reduce injuries and save lives.
*Children should ride in the back seat with seat belts on and/or in a child safety seat.
* Drive defensively, defensively, defensively.
*Dusk is a particularly dangerous time on intercity highways because most drivers delay turning on their headlights until well after dark. Oncoming traffic can be very difficult to see.
*Situational awareness is imperative.
*Use horn to alert pedestrians.
*Use horn and lights to alert other drivers.
*Pay attention when other drivers use their horns.
*Check all mirrors, particularly the right side mirror, and use directional signals when changing lanes.
* Confirm with direct visual check. Do not rely solely on mirrors.
Use four-way flashers to warn other drivers of slowed/blocked traffic to avoid being hit from behind.
*Expect the unexpected.
*Drive each day as though you were on a mission, the goal of which is not to be involved in an accident, cause an accident, or strike a pedestrian.
*Watch out for trucks and buses that take the right-of-way without signaling, whether they are entitled to it or not.
*Keep lights, signals, horn and brakes in proper working order.
* Be extremely attentive and situationally aware during rain and snowstorms. Accidents increase dramatically during storms, particularly at night.
*Assume nothing. Make no assumptions about what another driver may do or how they will react in a situation.
*If confronted by another driver, stay in your car, lock the doors, and use your cell phone to call the police.
*The maximum speed limit on the highway is 90 KM/hr; on the TEM and similar interstate-type highways, 120 KM/hr; and the maximum speed limit in the city is 50 KM/hr. Please note that all speed limit signs are posted in kilometers per hour and not miles per hour.

Aside the fact that I think their Defensive approach is a bit funny, here's something i've found on a site with driving rules.. Seatbelts are mandatory but child safety seats are not mandatory.

Thanks for this Spring......sounds like a nightmare but I'm sure I'll get the hang of it!!

yeah it does sound a bit scary especially the part about "If confronted by another driver"...

anyways... i am sure you will be fine and if you have any other questions, i'll be happy to google the answers for you