It would be interesting to compare the number of equipment related crashes in states with inspection and without inspection.
It appears the split is about 50/50.
Here are the inspection states:
Arkansas, California, Delaware, District of Columbia, Hawaii, Louisiana, Maine, Maryland, Massachusetts, Michigan, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia and West Virginia.
South Carolina did away with vehicle inspections years ago.