Well many of the newer small cars are built with better safety engineering and with better materials for withstanding crashes. Another thing you forgot to mention was that most cars these days have ABS which actually helps you avoid getting in a wreck, traction control and stability control help even further, but most cars don't have those two features as standard. The new Corolla you have received excellent crash test scores for front and side impact collisions. You might be surprised that even with the additional heft and weight, some bigger cars perform poorly in these crash tests. It would be wrong to just assume... you can look up the specific crash-test scores for the cars you're comparing for a source of objective judgement.

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1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver