The signing of the contract comes less than two months after the consortium was appointed preferred bidder.
The DHQs and custody facilities will be located in Leeds and Normanton, while the training centre, which will include firearms training ranges, driver training and public order training facilities, will be next to the force's Operational Support Division in Wakefield.
Interserve, which also builds and manages military training facilities for the MoD in the Defence Training Estate, will provide facilities management (FM) services at all the locations for 25 years after completing the construction.
It is anticipated that the Normanton DHQ will be available by the end of 2013, with the training centre and Leeds DHQ following in the first half of 2014. The total design and construction cost will be £100m and the FM cost will be approximately £50m over the 25-year period.
Interserve and consortium partner Equitix, the infrastructure developer and fund manager, will each invest £4.3m in the project.
Interserve chief executive Adrian Ringrose said: "These police facilities represent a key element of regional infrastructure, so we're obviously proud the Authority has entrusted Interserve with creating and supporting them. We're already heavily involved in the region, having worked here for many years. We've built facilities such as the Winter Gardens in Sheffield and the flood defences in Ripon, and we have a 10-year strategic partnership with Leeds City Council through which we're constructing and managing a number of schools and other amenities. Recently we acquired the Leeds-based welfare-to-work business BEST, through which we're helping the long-term unemployed in South and West Yorkshire back into work."
A spokesman for West Yorkshire Police Authority said: "The construction and operation of these new facilities will provide a timely boost for the local economy. At least 85 per cent of subcontracts will be awarded to local companies, and at least 65 per cent of construction staff will live locally. Interserve has also made detailed commitments to support skills and training for young people, including a firm commitment to support 85 young people across West Yorkshire to access apprenticeships."
Photo below shows the new Wakefield divisional HQ.