Delivery precision and fleet optimisation are highly prioritised within the ready mix concrete industry. Introducing a Global Positioning System (GPS) for logistic steering and planning provides a tool to make improvements on these areas. Such a system is presently under evaluation at a ready mix concrete supplier in Stockholm, Sweden. The system consists of GPS receivers in the trucks that send relevant information via the General Packet Radio Service (GPRS) net to a server. A direct effect of implementing a GPS system is that the plants and the order central will be able to better control the whereabouts of the concrete trucks. As a result it will be possible to decrease the waste time at the plants. Another result is that the ratio of usage of concrete trucks will increase, leading to cut-downs in the truck fleet. It is further believed that the lead-time at work sites can be reduced as the delivery precision is improved. By eventually letting the contractor be a part of the system the possibilities for a good production planning at the work site will increase and the non-value adding activities will decrease due to reduced waiting time. The article presents findings from a pilot study in Stockholm, Sweden. An important ambition is to find out if the system gives the expected benefits. The customer value is evaluated through interviews and time measurements.