As increasing amounts of intercity freight are transported by trucking firms, the possibility of constructing truck-only lanes along selected rural Interstate highways warrants consideration. On heavily traveled sections, there is potential for improvements in safety and productivity if such lanes were added. In this paper, we explore the conditions under which investment in truck-only lanes could be considered and what sorts of benefits may accrue to both occupants of passenger vehicles and to operators of heavy trucks. Then we examine the available evidence regarding the nature and magnitude of these benefits to gain insight into the willingness of highway users to pay for these lanes. We conclude that the willingness to pay for truck-only lanes on the part of occupants of passenger vehicles appear to be quite limited and that support for these lanes on the part of trucking firms is likely to depend upon their being allowed to operate longer-combination vehicles (LCVs) on them. Trucking firms could be assessed tolls to travel in truck-only lanes, with these tolls representing some fraction of the increased productivity gained through being allowed to operate LCVs. Finally, we pose several questions that would need to be answered before an investment in truck-only lanes might be considered along a given Interstate segment.