Yes, you can request discovery. Although in a traffic case there may not be much 'discovery' beyond the copy of the citation itself. Generally, in traffic cases the officers do not write an actual narrative report. When/if relevant you can request radar calibration logs, radar certification docs, traffic cam pics/vids, etc. Best to consult a local attorney though, to guide you on all this. Good luck.
You are entitled to discovery of the reports on your case at any time. Although in a traffic case, there may not be much more than the citation, as officers rarely write reports for simple speeding violations.