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I cannot put my finger on it or know the name of the site, but there is a site that provides test results on commercial bus chassis after a significant number of simulated miles. It reports broken welds, chassis deflection, and any other damage relating to thouseands of miles of wear and tear.
There are damages on some chassis like broken welds on tie rod attach points, and some chassis have deflection not present after the testing, but surprisingly a commercial chassis twists so little the amount is in minor fractions of an inch.