Depends on the radar system. Some are distance only without direction. Some are 1D (a line, usually horizontal) and some are 2D. Many objects are partially opaque, which is confusing. Resolution is very poor compared an optical device of the same size.
> Could multiple radar emitters and receivers be used to create a phased array and improve resolution?
Yes. However, this is currently bulky and expensive (in dollars and in compute power). Thankfully, it looks like capitalism is coming in to the rescue here and miniaturizing the everloving shit out of complex radar arrays for human interface tech. This should be usable for vehicles as well.
All the automotive radars are phased array devices, and have been since the Eaton VORAD of the late 1990s. No moving parts. They're usually 1D scan (horizontal) only, although 2-axis scanned automotive devices exist.
http://www.radartutorial.eu/01.basics/Range%20Resolution.en....
For angular resolution: http://www.radartutorial.eu/01.basics/Angular%20Resolution.e...