Did you get a police report? Are there witnesses? Was anyone drunk? Is there a videotape? These things depend on specifics greatly, as a collision is not a collision, they are all unique.
Are you being sued for personal injury? If so talk with a local lawyer offline ASAP.
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Your question is unclear. Often times, parking lots do not have clear designations as to proper direction of travel. You should turn the matter over to your insurance company for coverage and defense. That being said, you should always yield the right-of-way to oncoming traffic when backing out a parking space. However, if the other vehicle was traveling the wrong way on a one way street, there would likely be comparative liability attributed to one or both of the parties. If the other vehicle was traveling properly on the roadway, the vehicle backing out of the parking space would likely be at fault for the accident. There is no way to know for sure without a proper investigation regarding the details of the accident. Your insurance company will do an investigation.
The devil is, as usual, in the details. Expand your question with more facts and consult a local lawyer who knows the lot and street where you had the collision. Good luck.
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