Local environmental leaders fear that without the implementation of RTA Next (RTA Next), crucial wildlife linkages will lose funding. The original RTA plan was passed in 2006, with voters approving a half-cent-per-dollar sales tax to fund a 20-year, $2.1 billion package of road and transit improvements. The plan includes $50 million for wildlife crossings between now and 2046, less than 2 percent of the overall spending, but these projects are vital to connecting Pima County’s sensitive lands and allowing wildlife to move across the region. Critics argue that the RTA's plan would spend too much on roadways and not enough on buses and bikepaths. Some opponents argue that it would result in more sprawl and the city should abandon the regional RTA entirely, with its own sales tax plan more heavily weighted to transit and alternative approaches.