China's government has warned taxi companies around the country to prevent possible strikes by cabbies upset at a rise in gas prices this week. Taxi drivers from several provinces have converged on Beijing in recent days to petition the government. They complain that government monopolies and a lack of independent unions mean cabbies and consumers -- but not the taxi companies -- are bearing the brunt of the price hike. NPR's Anthony Kuhn rides with and talks to taxi drivers whose efforts to organize unions and protests have been thwarted.