The Taliban have made considerable gains in fighting in various parts of the country in recent months and the killing of their leader, Mullah Akhtar Mansour, in a US drone attack last month has had no discernable impact on the violence.
Attackers in the eastern province of Ghazni stopped two cars late on Tuesday and shot dead everyone they found. Several members of the security forces were among those killed, said Jawid Salangi a spokesman for the provincial governor.
"Taliban ordered the passengers out and brutally shot them dead," Salangi said.
Villagers later found 12 bodies, he said.
Taliban spokesmen were not immediately available for comment.
Also on Wednesday, suspected Taliban stopped a bus and a car near the northern city of Kunduz and took all 50 people in the vehicles hostage, a police spokesman in the area, Mahfozullah Akbari, told Reuters.
"We are putting all our efforts into freeing them as soon as we can," he said.
Travelers have faced a string of murders and kidnappings on roads in recent weeks.
Militants killed at least nine people and kidnapped 20 when they held up three buses in Kunduz late last month.
The Taliban claimed responsibility for that kidnapping.