I improved the quality of RT reflections in the Enhanced version of GTA 5 and also added RT reflections to the surfaces that should've had them. A lot of assets needed to be updated:
Buildings, houses, apartments and businesses have proper ray-tracing reflecting windows and glasses
Fixed translucent surface reflections
Puddles and bodies of water now also reflect properly
Building LODs are also adjusted for smooth reflection transitions
Added proper shaders and textures to models such as underpasses to take advantage of RT reflections
GTA V: Definitive Edition Improved RT Reflections: DOWNLOAD
Currently the majority of the city is updated to fully take advantage of the new RT technology.