A green wave on a road enables a driver to negotiate a sequence of signalized intersections without hitting red. This is accomplished by the coupling of a series of signalized intersections. This is an advantage for driver comfort, for flow and safety on the road network, and for the environment. Providing speed advice may help the driver to benefit successfully from a green wave. Variable message signs are being used in several green wave situations, the use of an in-car display for this is new. In this driving simulator study the effects on driving behavior, workload and user acceptance were measured by comparing an in-car display with a variable message signs (VMS) roadside system. Green wave speed support resulted in a change in driving behavior compared to no support system. Using the in-car display, participants drove more slowly and at a more constant speed compared to the baseline condition. Participants had to stop less for traffic lights using the in-car display than VMS. Compared to the baseline condition, using the in-car display did not result in a higher workload whereas VMS did, though most participants found the VMS system more satisfying than the in-car display and preferred VMS. Participants followed the green wave advice because it would reduce fuel consumption and benefiting from a green wave was considered pleasant. Green wave speed support is promising for improving traffic flow and driver comfort on a road network. Based on the findings of this study, the in-car display performed best.