A six-year-old boy and his father were killed early Monday when a coach bound to Nalchik, in the North Caucasus, capsized about 310 miles south of Moscow.
All 27 passengers on board were injured and seven remain hospitalized. According to preliminary reports, the driver either lost control or fell asleep at the wheel.
The second accident occurred Sunday at 1:45 p.m. Moscow time (9:45 a.m. GMT). A driver of a Lada car crossed into oncoming traffic and collided with a minibus. The driver, his three passengers and a man in the minibus died at the scene.
The network of Russian highways is one of the world's longest, but only 20% of regional roads meet international safety standards. The Don federal highway is considered one of the country's most dangerous.
On August 21, a car pileup involving about 35 cars blocked traffic on the bridge across the Oka River in the Moscow Region. Poor visibility caused by fog is said to have triggered the tragedy, in which at least four people were killed and six injured.
Two weeks ago an accident involving two cars occurred in the Lipetsk Region, killing five.
Russian authorities begun improvement work to the highway. On August 22, the Russian government launched an investment project costing 186.6 billion rubles ($7.3 billion) to build a toll road from Moscow to Novorossiysk through Voronezh, Rostov-on-Don and Krasnodar.
