Stores with dangerous or cramped parking lots can be the target of this complaint letter regarding safety.
Your parking lot is intolerable. While I love shopping at your store, my visits are becoming less and less frequently due solely to the unsafe conditions of your parking lot.
The lot is not only too small, its individual stalls are too small. I've lost count of how many fender-benders, near misses, and "road rage" incidents I've witnessed there. The last straw was when I had to render emergency aid to a pedestrian who was hit by a car backing out of your cramped lot.
If you are unable to resolve this issue with your landlord, your next step should be to look for a new location. Otherwise, you will continue to lose customers, not to mention open yourself up to legal liability.
Feel free to share this complaint with your landlord.