A group of Colorado senators is frustrated by the slow pace of a House bill to ban cities from using red-light enforcement cameras. So they’re forwarding a rival measure to compel towns to get voter approval to keep the cameras. The Senate is scheduled to vote this week on the bill, which takes a new approach to getting rid of the hated cameras. Instead of banning the cameras, the state would tie transportation funding to a requirement that cities with the cameras seek voter approval. Efforts to ban the cameras have stalled for years in the state Legislature because cities say the use of the cameras should be up to them. A red-light camera ban has been pending in the House for weeks.