According to Consumer Reports, car seats for infants (the rear-facing seats for infants up to about one year in age) usually fail in broadside crashes — 10 of 12 models tested failed, some “disastrously” (the seat often separated completely from its base). One popular model — the Evenflo Discovery — failed not just in broadside collisions but also in head-on collisions.
One possible explanation for the failures: the manufacturers are only required to test infant seats in head-on collisions, despite that about 30 infants in the United States die each year in broadside collisions.
Parents are cautioned, however, that holding an infant in your arms during car travel is not a safe alternative.