Usually, you stop by the CHP office that handled the collision and pay around $10. or so for a copy of the report. If everything is as you say and you and the 4runner were stopped when the corolla initiated contact...you are definately not at fault. Party #1 (P-1) would be the corolla (P-1 in any CHP report is ALWAYS referenced as the party at fault). The 4runner would be Party #2 and you would be Party #3. The primary collision factor (PCF) would be California Vehicle Code section 22350 (Unsafe speed). If nobody was injured or transported to the hospital, the document written by CHP will be in "report format" (a short version of the officer's findings.) If injuries were sustained by any party...even a complaint of pain...it will be a longer version written in "investigation format" (provides much more detail.) Either way, the copy you obtain will clearly show which party is at fault. If you run into any issues with insurance companies not wanting to pay, the CHP report will come in handy.
