Driving in Istanbul can be challenging for newcomers to the city. Besides the often congested traffic, locals tend to not hold fast to road rules and regulations. It is a good idea to book at GPS to avoid the many one way streets you will otherwise encounter. Parking can be limited as well, so make sure your hotel has designated parking spaces or look into ones that have valet services. While out and about you can look for covered or open air parking lots, especially in business and commercial districts like Taksim.
The main roadways are the O-1, O-2, O-3, and O-4. The O-1 is an inner ring which crosses the 15 July Martyrs Bridge, popularly called First Bosphorus Bridge, which connects Ortaköy on the European side to Beylerbeyi on the Asian side. The outer ring, O-2 crosses the Fatih Sultan Mehmet Bridge, or Second Bosphorus Bridge, and spans the Bosphorus Strait. A Third Bosphours Bridge, Yavuz Sultan Selim Bridge, connects the two continents from near to the Black Sea and Beykoz on the Asian side. Getting between both halves of the city is also possible with the Eurasia Tunnel connecting Kazlıçeşme and Göztepe. Be aware that most bridges are tolled routes and only accept electronic payments. The European E80 runs through Istanbul as well.