Take a few minutes to bring your resume to life for the interviewer. Once you have highlighted the bulk of your experience, you can discuss some of your favorite projects or areas of interest. Avoid talking yourself into a corner when it comes to your preference of public vs. private projects. Be as diplomatic as possible by highlighting the pros of each.
"For the past four years I have been working with ABC, in the private sector. Some of my favorite recent projects have included X, Y, and Z. With that said, I also bring public sector experience from earlier in my career. That experience was also helpful because it taught me a lot about process and navigating the red tape associated with government projects. I have learned a great deal from both public and private work."
"I have a balance of experience between public and private transportation. I have three years' experience in public transport and four years' experience in private transportation. The two sectors bring their challenges, so it is difficult to choose a preference. If I had to commit to just one, I would say that private transport brings me fresh challenges daily, which is exciting to me."