In Managua, those who commute to and from work generally travel by bus or taxi. Taxi tends to be the transportation method of choice for tourists. Taxi cabs may be hailed or called over by radio dispatch. Street cabs, those that can be hailed without calling a dispatcher, are widely available and cost somewhat less than their counterparts. However, some taxi cabs operate as collectives, and do pick up passengers as the first customer goes on their journey. Usually, passengers that wish to opt out of such practice do so by advising the driver not to pick up additional passengers. This is usually done as a safety precaution, as there have been robberies committed due to this practice of "cab sharing." Taxi cabs do not have meters. By custom, many Nicaraguans and tourists alike agree on a fare before embarking on the vehicle.