A few things besides calling 911:
1) Try get consent from her parent or guardians if they are available, if you can't find them, you get default YES.
2) Try not moving her, because she may have spine injury. Set sign or call other people to help stopping the traffic.
3) Stop bleeding with bandage or clothes strips.
4) Keep her body warm by covering her with blanket or something else.
5) Keep her head higher, pull out the tongue if she is choking with her blood.
6) Give CPR if she stop breathing, don't STOP till the professional health worker coming to help.