We have a Constitutional Amendment referendum on just such an issue in Illinois.
If passed it will require that any taxes, bonds or other measures passed to build or improve roads and other transportation infastructure be used only to build or improve roads and other transportation infrastructure and not Blagojevich'd* to pay for other .gov projects.
*- The term I use for .gov Bait and Switch when it comes to revenue. Blagojevich turned it into an art form while bankrupting this state to pay for his pet projects and bullshit contracts to pay off political friends and donors. As an example, Blago damn near zero'd out the DNR budget leaving them to operate for several years on nothing but Pittman-Robertson% funds from the feds. He tried to even take those funds to use elsewhere in his budgets until the Feds slapped him down and prevented it. IIRC, I think he even took the moneys raised by selling Hunting and Fishing licenses and the various stamps associated with those licenses to use for other non-DNR purposes.
%- If you don't know what they are, google it. Chances are you pay them, and probably a lot of them. My Hunter Ed Students, along with deer, turkeys, songbirds and everyone else who enjoys public lands thank you.