At least three firebombs were thrown at vehicles passing near the city of Shechem, north of the Jewish community of Yitzhar.
No one was physically hurt in any of the attacks. IDF soldiers launched a search for the attackers.
Firebomb attacks on Israeli motorists by Arab terrorists have become more frequent in recent months, as have rock attacks.
Further south, PA Arab terrorists likewise targeted Israeli motorists with rock attacks in Judea earlier Monday evening. A bus bearing Israeli license plates was damaged in one such attack while passing the Arab village of El Aroub.
Last month an Israeli man was wounded in a firebomb attack in Samara as he drove near the Jewish community of Karnei Shomron, north of Jerusalem.
Jews living in Judea and Samaria warned earlier in the year that terror on the road was likely to increase after Highway 60 and Highway 443 were opened up to traffic from the Palestinian Authority.
The Supreme Court ruled in 2009 that the highway, a major artery connecting northern Jerusalem with the city of Modi'in and Ben Gurion International Airport, must be open to Arabs from the PA despite the risk of terrorism. Highway 443 has been closed to PA traffic since the Second Intifada in 2002 because of dozens of terrorist attacks on the road.