Yes. You can apply RTI to Gujarat State Road Transport Corporation. 
Gujarat State Road Transport Corporation is a state owned corporation that was established on 1 May 1960. Gujarat State Road Transport Corporation (GSRTC) is a passenger transport organisation providing bus services both within Gujarat and neighbouring states. Hence its a public authourity as per sec 2(h) of RTI act 2005. So, you can apply RTI.
For more info on RTI please check  https://onlinerti.com/