Allstate did this "15th Annual Allstate America's Best Drivers Report" which ranked 200 U.S. cities by collision frequency using claims data to determine which markets have the safest drivers. Vegas was ranked 129. Honestly, I'm surprised we didn't do worse, having driven in New Jersey, Connecticut, Florida, North Carolina and now Nevada (specifically Vegas).
This city's issue with unsafe driving to me stems around driver ignorance. I can't tell you how many times I've almost gotten hit by another car changing lanes most likely because they didn't look to see who was coming. You have to try and predict what other drivers may do in this city. When I was preparing to move here from the east coast I was told Vegas is the second most expensive city in the country for car insurance. Now, I know why!