The driver, Raluca Musat, and her friends were heading for capital city Bucharest after they had spent the weekend on the seaside.
The Constanta road police department said the youngsters were coming from Mangalia and heading for Constanta, adding the accident occurred near the 23 August location because the driver did not adapt the speed to road conditions.
Ştefania Dumitrescu, 22, died instantly while Raluca Musat, Iustinian Miu, 19 and Marian Andrei, 22, were severely injured.
The three survivors were rushed to the Constanta County Emergency Hospital, but their condition is stable.