Value pricing, or congestion pricing, includes a range of different tools that center on the theme of using peak-period tolls to reduce urban traffic congestion. Because tolls are charged only on congested roads and only during peak periods, drivers are given a direct financial incentive to find different routes, modes, or times of day to travel. Current implementations of this idea include varying tolls by time of day on existing toll roads and bridges; and allowing solo drivers to buy access to high-occupancy vehicle lanes, at a toll that varies so as to keep these lanes free flowing.