BERLIN (AP) — German automaker Daimler is investing more than $10 million in chauffeur service start-up Blacklane.

Daimler said it was investing an "eight-digit" sum in the service that operates in more than 50 countries worldwide.

Blacklane allows users to book self-employed chauffeurs for a fixed price. The service primarily targets business travelers, whereas rivals such as Uber have focused on a broader customer base.

Daimler said in a statement Monday that the market for professional ride services is estimated to be worth about $30 billion a year at present.

The maker of Mercedes-Benz cars has invested heavily in transportation services in recent years, including the cab-hailing app mytaxi and car-sharing company Car2Go.