DETROIT, Dec. 18 — Small cars are back in vogue because of high gasoline prices but most fail to provide the same safety protection that buyers find in bigger vehicles, according to the results of new tests simulating crashes with sport utility vehicles or pickup trucks.

All eight models of small cars tested by the Insurance Institute for Highway Safety received passing scores in head-on crash tests, but only one, the Nissan Versa, received high marks in both side- and rear-crash tests. The Versa is several hundred pounds heavier than competing models and therefore was better able to withstand the test impact.

Three other models — Toyota Yaris, Honda Fit and Mini Cooper from BMW — scored well in side tests but received low ratings in rear tests.

The results, which are being released Tuesday, show that some small cars offer significantly better protection than others, but experts caution that even the safest subcompact car cannot overcome its inherent size and weight disadvantage. On average, subcompacts weigh about 800 pounds less than midsize cars like the Toyota Camry and 4,000 pounds less than midsize S.U.V.’s like the Ford Explorer.