Apr 16, 2015 Berlin A Berlin court has upheld a ban on the U.S-based online taxi service Uber, which allows users to summon a ride with their smartphones, saying the company did not comply with German laws on the carriage of passengers. The ruling by the Berlin-Brandenburg Higher Appeals Tribunal confirms a ban from last August that prohibited the service because it did not offer drivers and vehicles licensed to carry passengers or provide full insurance cover. Uber drivers are private citizens who use their own cars to pick up the service's customers. Uber, the world's most valuable venture-backed start-up with a valuation of $40 billion, is facing increasing legal challenges across Europe, where local taxi drivers have taken to both the streets and courts to fight it. It has been criticized worldwide over how it pays drivers, charges passengers and ensures their safety. Taxi companies argue it competes unfairly because it does not have to pay their steep license fees and bypasses local laws. Last month, a German court banned Uber from running services using unlicensed cab drivers and set stiff fines for any violations by Uber of local transport laws.