Police reports in New York State do typically list an insurance company by a three digit code. The NYS Insurance Department has a link on their site to look up the insurance codes written on your accident report.
The NYS Insurance Department insurance code look up will help you locate the name and address of the company in question. You may also contact this NYS state department at 212-480-6400 or 1-800-342-3736 for help with deciphering the insurance codes listed on your New York State Police Accident Form.
You should do the insurance code look up yourself with the information you have to get more information but we can give you some basic information. From what you listed it appears that 011 stands for Allstate Insurance Company. D11 does not appear to be an insurance code number so if it not 011 than you can also look up the insurance code by the name of your insurance company. So if Allstate is not your insurer than look up your insurance company's code through looking up the name of your insurance provider on the NYS Insurance Department's look up site.
Insurance code 646 stands for Allmerica Financial Alliance Insurance Company. When you look up the insurance company by its code their address and phone number is listed so that you can call in a claim if you do not have another number in which to use and get your claim started.