The presence of HOT lane projects is an indication that a state is amenable to charging tolls on their highways, which is a common method of revenue collection under the more private PPP models. Many states have HOT lane projects in place or under consideration, and these variable toll facilities are the only allowable way to toll existing free HOV lanes (Gougherty 2005b). It should be noted that many states have traditional, non-HOT toll lanes, and these are not accounted for in the "HOT Lane Projects" column.