The American runner was on her way to work in the Oklahoma City, Oklahoma when another vehicle ploughed into her and flipped her vehicle upside down.
Via social media, her husband, Conor Holt, confirmed that she was extremely lucky, and is fine, but is shook up after the incident.
Last year she withdrew her title defence due to an injury.
The good news for running enthusiasts is that Herron is still planning on making her return to South Africa this year, and she will still be able to defend her "up run" title between Durban and Pietermaritzburg.
In 2017 Herron won the iconic ultra-marathon in 6:27:35, becoming first American to win the Comrades in 20 years.
The 2019 edition of the iconic South African ultra-marathon will be run on Sunday, 9 June.
@MorganPiek OFM Sport