alt Hacker NewsA completely unremarkable day, more like it. Given stochasticity there's bound to be at least a dozen days per year with 50% more than the average, especially since car deaths depend a lot on weekday, holidays, weather and so on - much moreso than train deaths. No one would look up from it, wouldn't make the news.
You're assuming it was the only incident in America that day, rather than an exceptional outlier stacked on top of the usual day in America.
Yes, a single car crash killing 150 people would make the news. It would be among the worst, if not the single worst, car accident of all time [0].
[0] https://en.wikipedia.org/wiki/Multiple-vehicle_collision