Maybe. If you’ve been convicted of a felony usually within 10 years of the car accident, sometimes the other side, the defendant, can use that felony to say that you’re not a trustworthy or credible person. This argument can be effective if you’ve been convicted of a felony like embezzlement or something where you lied or concealed something, insurance fraud, fraudulent checks, stealing from people, etc. It’s less effective for other crimes like possession of narcotics.
Nevertheless, it still has some bearing on the case and some jurors could throw all your testimony out. If you’ve been charged with a felony while the case is ongoing and haven’t been convicted yet, you could most likely keep that out since it’s not relevant, and overly prejudicial. Once the other side finds that out, they will use it against you in settlement negotiations and probably try to push the trial out to see if you’ll get convicted.
I’ve handled a number of cases where my clients had a felony conviction. I’ve been able to get good results for them but it does affect the settlement value.