Rhode Island is trying once again to keep a trucking industry lawsuit that could tear down the state’s truck toll system out of federal court. At issue in the appeal is whether truck tolls are a user fee or a tax. The Tax Injunction Act bars federal courts from blocking state taxes. U.S. District Court Judge William Smith ruled last March that the tolls are a tax, and dismissed the case, but the appeals court decided the tolls were fees and reversed the decision. Lawmakers authorized tolling tractor trailers on Rhode Island highways in early 2016 and, despite the lawsuit, the state has begun collecting tolls at five locations across the state. The next toll expected to launch is on Route 95 where it crosses Route 117 in Warwick.