Must one who takes a taxi and then exits it before reaching his destination pay the fare to the driver?

An ijara (lease/hire) is a binding contract that cannot be unilaterally terminated except by mutual consent. Riding in a car or bus may be considered an ijara based on common custom. Custom varies from country to country; in some places, the passenger is not obligated to pay the fare merely by boarding, but rather when the vehicle departs for the intended destination.