53 Pa. Stat. § 13803
Any city of the first class undertaking any improvement, authorized by the foregoing section, may acquire any land and property necessary therefor, either by gift, purchase, or the exercise of the power of eminent domain. Such city may also, in like manner, acquire and take more land and property than is needed for the actual construction of such improvements, or any of them; but the additional land and property, so taken, shall not be more than sufficient to form suitable building sites on such highways or streets, nor shall such additional land and property be acquired at any point more than three miles distant from the approach to any such bridge or tunnel. The title, which the city shall acquire to all land and property under the provisions of this section, shall be fee simple absolute.
53 P.S. § 13803