It depends on whether they bear the main responsibility or all the responsibilities. If there is no evidence above the main responsibility for serious injury, it is enough to be a traffic accident crime, and they shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention.
 According to the Interpretation on Several Issues Concerning the Specific Application of Law in the Trial of Criminal Cases Involving Traffic Accidents
 Article 2 Whoever commits a traffic accident under any of the following circumstances shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention:
 （1） One person died or more than three people were seriously injured, and they were fully or mainly responsible for the accident;
 （2） More than three people died, and they are equally responsible for the accident;
 （3） Causing direct losses to public property or other people's property, bearing all or the main responsibility for the accident, and being unable to make compensation of more than 300000 yuan.
 If a traffic accident causes more than one person to be seriously injured, bears all or the main responsibility for the accident, and has one of the following circumstances, he shall be convicted and punished as a traffic accident crime:
 （1） Driving a motor vehicle after drinking or taking drugs;
 （2） Driving motor vehicles without driving qualification;
 （3） Driving a motor vehicle knowing that the safety device is incomplete or the safety mechanism fails;
 （4） Knowingly driving a motor vehicle without a license plate or which has been scrapped;
 （5） Serious overload driving;
 （6） Escaping from the scene of the accident in order to avoid legal investigation.