Actually, it doesn’t cost anything to Adopt a Highway, but that’s because adopters do all of the maintenance work using safety equipment issued by their state’s Department of Transportation. They are also required to attend safety training, also hosted by the Department of Transportation. This program saves taxpayers money on road repairs by relying on volunteers instead.
If you just want to contribute to your local roads financially, you’ll be better off with the Sponsor a Highway program. This is a monthly payment service with contribution amounts ranging from $200 to $600 per month. This is often done by major corporations as a form of advertising, as billboards visible from the highway cost closer to $7,000 to $14,000 per month.