While New York certainly does have elevated highways, its hard to say how many other areas do or do not have elevated highways, largely hinging on what one defines a highway(or elevated) as. There are many rapidly developing countries throughout the world, and their infrastructure isn't often taken into account in these questions.
This questions refers mainly to the "Viaduct" in Syracuse. Though rare, elevated highways do exist in other parts of the world, mainly South America and China. According to a Google search I conducted, Shanghai, China has as many as nine elevated highways. I concluded that New York is not the only place with elevated highways.