Not necessarily. However, it does help. When it comes to car accidents, civil cases and criminal cases are two separate issues. This means that if a driver was driving drunk and the court decided they were not guilty, you can still pursue damages from that party. Conversely, even if the driver received a ticket or entered a guilty plea, that does not mean the insurance company will automatically issue a check.
Insurance companies look for ways to minimize their liability. This means that even if there is clear proof that their party is guilty, they will look for ways to show that you contributed to the accident or that your injuries were not the result. This is why you should always work with an experienced personal injury attorney, no matter how straightforward the case may seem.