Question: Why do some Jews refrain from driving in cars on the Sabbath?
Answer: Shabbat is observed in various ways by Jews, and this is well illustrated by the use of cars.
Orthodox Jews do not drive cars on the Sabbath because it involves lighting a fire. Starting a car is like creating a fire, which burns fuel and gives the car energy. Kindling fire is one of the 39 types of work that the Torah prohibits on the Sabbath.
Some Conservative Jews and Reform Jews will drive on the Sabbath for specific purposes such as going to synagogue or visiting family and friends. They are observing the spirit of the Sabbath day, but not strictly following the Biblical prohibitions.
The majority of Jews today do drive cars on the Sabbath. Aproximately 80% of Israelis drive on the Sabbath. They drive cars either because their interpretation of "Sabbath rest" differs from the traditional Biblical reading or they simply do not actively practice Judaism.