Officer Cooley

No. However, Non-ELS vehicles can arrive with lights and no sirens on which is configurable in the ultimate backup ini file. But if you have ELS cars installed, then they will always arrive code 3 with sirens if code 3 is set. you can change els vehicles to show up with no lights and no sirens as well. But no code 3 just lights option since the coding for that hasn't been configured yet.  Although, I believe rich's police enhancements has the option for all backup to show up code 2 with no sirens and lights until they reach your proximity. If you have your lights on, when they reach a certain distance from you, theirs activate too. But with sirens as well if the backup vehicle is ELS.  Maybe you can give that a try? Or use Non-Els vehicles in vanilla slots and run addons for you to get what you are asking for.