Transport for London (TfL) has awarded Yunex Traffic a £200m contract to install and maintain traffic signal assets across the UK capital.
From 1 August, the deal covers 21 of London's 32 boroughs plus the City of London business district.
Yunex will be responsible for the maintenance of more than 4,000 traffic signal sites, 91 variable message signs (VMS) and 30 over-height vehicle detector sites.
The 10-year contract also includes the design, supply and installation of new infrastructure.
Carl Eddleston, TfL's director of network management and resilience, says: "London's road network plays a vital role in enabling millions of journeys each day and we're determined to ensure that people can walk, cycle, take the bus and drive as safely and efficiently as possible."
TfL has also signed a contract with Telent Technology Services to maintain its network of CCTV cameras.
"We're delighted to have signed this new customer focused and greener contract with Yunex Traffic and Telent Technology which will ensure that infrastructure across London is well installed and maintained for years to come," Eddleston added.
Wilke Reints, MD of Yunex in the UK, said: "Having worked closely with colleagues at TfL over a long period, we have developed a deep understanding of the requirements of this unique traffic environment, and look forward to helping keep the city's road network operating safely and efficiently and improving the air quality for those who live, visit, study and work there."