If a motorcycle rider witnesses a traffic accident, they are **obliged to assist or request assistance** to help the victims **as soon as possible**. This is because failing to help the victims of an accident, when it is possible to do so without endangering oneself, is considered a crime called **failure to render aid**. This crime can have serious legal consequences, such as the possibility of going to jail.

Furthermore, all witnesses of a traffic accident must follow certain steps, such as **attending to the victims or calling for help** so that someone else can assist them. It is also important to collaborate to prevent further harm and help restore safety in traffic.

In case it is not possible to help directly, it is essential to **notify the authorities** so they can intervene. If emergency services have already arrived, it is best to keep moving to avoid obstructing the accident site.

Therefore, the correct answer is that yes, a motorcycle rider must assist or request assistance as soon as possible.