Outsourcer Affiliated Computer Services said Thursday that it has acquired Orbital Sciences Corporation's Transportation Management Systems business for $42.5 million.

TMS provides public transit agencies and transportation companies with computerized fleet management tools that use global positioning systems to track vehicles. The unit posted about $50 million in revenues in the 12 months prior to the end of March 2008, according to ACS.

ACS executive VP Michael Huerta said in a statement that the acquisition will strengthen ACS's "end-to-end transportation services." The deal will be financed through a combination of existing cash and borrowed funds, ACS said.

Fleet management systems are becoming increasingly critical for public transit agencies and other transportation concerns due to the rise in fuel prices. Organizations typically use such systems to ensure that vehicles are following the most efficient routes possible and also to keep tabs on drivers.

TMS has more than 60 customers, including the Nashville Public Transit System and the Tampa Transit System.

Dallas-based ACS provides a number of transportation-related services to governments and to the private sector, including E-ZPass electronic toll collection, airport and urban parking systems and photo radar systems.

Last month, the company won a five-year, $25 million deal to build a camera-based traffic enforcement system for the city of Winnipeg in the Canadian province of Manitoba. ACS provides similar services for cities in the provinces of Alberta and Ontario.

ACS chairman Darwin Deason last year attempted to take the company private, but the plan was rejected by ACS's board.

ACS shares were up 1.30% to $51.99 in late morning trading on Thursday.