Q: How can the DA pick up charges on someone after the fact

A: What you characterized as merely a minor traffic accident must have escalated into a much more serious situation where the person charged with ADW (Assault with a Deadly Weapon) threatened the other party with GBI (Great Bodily Injury) using a weapon ranging from a knife, gun, etc. to something more innocuous like a crowbar, screwdriver, etc. which is capable of inflicting GBI.

First, the DA's Office files criminal charges based on recommendations made by the arresting and/or investigating Law Enforcement Agency. They don't file serious charges like ADW ) unless the arresting agency has obtained facts, witness statements and other evidence (such as the weapon brandished) to back up the charge.

ADW is considered to be a "wobbler" meaning it can be charged as a misdemeanor or a Felony. The maximum bail on a misdemeanor is $5,000. In light of the amount of the bail (98K), it's been charged as a Felony. The potential jail time for a Felony ADW conviction ranges between 2, 3 and 4 years in state prison. It also counts as 1 strike under California's 3 Strike laws.

In light of the above, it would be more productive for you to consult with and hire a skilled and experienced criminal defense lawyer in your area who handles serious and violent felonies like ADW's to go over potential defenses than act incredulous how the ADW could possibly be charged. Again, the charging deputy at the DA's Office in your county must be VERY confident they prove ADW beyond a reasonable doubt.