You can get almost anywhere in Israel by bus, and the Central Bus Station is a fixture in most towns: ask for the tahana merkazit. Egged handles most of the country's bus routes; Dan dominates in Tel Aviv. Both intercity and urban buses run from 5:30 am to 12:30 am Sunday to Thursday.
Note: Public transportation is suspended during the Jewish Sabbath (Shabbat), from about an hour before sundown Friday (depending on the line) until nightfall Saturday, although private minivans ply some lines in Tel Aviv. Haifa has a limited bus service on Shabbat.
Taxis can be a good option on Shabbat—they're plentiful, relatively inexpensive, and can be hailed on the street. Drivers must use the meter according to law. Sheruts are shared taxis or minivans that run fixed routes at a set rate; some can be booked in advance.
The train from Tel Aviv to Jerusalem is a scenic, 1¾ hour trip—not the quickest way to travel between the two cities. Commuter trains run efficiently between other cities; the majority of service runs along the coast, from Nahariya south to Tel Aviv, and then inland as far as Beersheva. Signs at train stations are posted in English. Reservations are not accepted.