You chances of escaping without a fine are slim to none, but you can probably keep it off of your driving record. You don't absolutely need an attorney, but one would help you navigate the process.
There are defenses to this citation that you can explore. For example, if there were vehicles in the other lane that prevented you from moving over, you are not required to do so. Similarly, it may not be a violation if the police did not have their emergency lights flashing. These are things that you may wish to discuss with an attorney to see if you have a defense worth pursuing.
At the very least, you should talk to the prosecutor about the offense. Though many jurisdictions take a hard line on these cases due to officer safety concerns, some will allow you the chance to keep your record clean. Good luck.