According to the Chicago Tribune, the Illinois Tollway Authority planning to sell advertising space on the sides of its HELP (for Highway Emergency Lane Patrol) trucks that, well, help drivers whose cars have become disabled.
The revenue from the ads will be used to defray the $2 million a year it costs to provide the service, according to the Tribune. But they're only the first step. The state department is also looking into selling naming rights on the tollway oases (like rest-stops but above the freeway), ads on the website and leasing space on the domes that store road salt.
Apparently, the program is modeled after a similar venture in New York, which raises $2.2 million a year. The first Illinois contract may be awarded in April.