Traffic authorities work hard to improve resource utilization in traffic. But these efforts do not consider that the valuations of waiting time can be different for each driver, e.g., a driver of a courier service delivering express mail typically has a higher valuation of reduced waiting time than other motorists. We propose that traffic-control mechanisms should be valuation-aware and propose and describe such a mechanism called Time-Slot Exchange. The idea of this mechanism is that vehicles are assigned time slots to cross the intersection, and vehicles, or, more specifically, agent-based driver-assistance systems of the vehicles can then trade these time slots. Simulations show that our mechanism increases overall satisfaction considerably, compared to a state-of-the-art traffic-control mechanism.