Spanish taxis refused to pick up passengers in a one-day strike Wednesday against the increase in cars run by private companies offering cheaper, mobile ride-hailing services.
The near nation-wide stoppage, directed against the San Francisco-headquartered Uber and Madrid-based Cabify services, was called after a court recently allowed new licenses for these firms.
Unions say a law stipulating that there should be one private cab for every 30 taxis is being flouted.
The strike left empty the normally packed taxi ranks at airports and train stations.
Thousands of taxi drivers took part in a demonstration from Madrid's main train station to a square near Parliament, causing considerable traffic chaos for most of the day.
Police maintained a strong presence in the area and cordoned off all side streets to the legislators' building.
The drivers blew horns noisily and set off firecrackers and color smoke bombs. There were brief scuffles with police as some protesters tried to break past the barriers set up to prevent access to the Parliament headquarters.
The unions have held several similar strikes in recent years. They said they would provide free services for the elderly, pregnant women and people with physical mobility problems during Wednesday's stoppage.