This video makes some good points about visual and drive-thru state vehicle inspections. Visual inspections are good at spotting neglect and worn parts. Drive-thru inspection lanes are better at spotting issues with brake bias and pulling issues. Except for the UK, not too many places do both a visual and performance inspection.
During the great recession many states cut back on inspection programs because it had little short term impact on safety. But, long term the effects of unperformed repairs is starting to cause a raise in traffic fatalities.