You can reach Roadside Assistance from anywhere in the US, Canada where there is cellular service via the Tesla App or by phone call. In most locations Tesla Roadside Assistance can dispatch a contracted tow service with a flat bed carrier to your location and have your Tesla vehicle towed. You will need to arrange your own transportation, i.e. Uber, etc. In some locations the tow service can bring you a loaner wheel/tire, otherwise your vehicle will need to be towed. (I believe that Tesla will only send a tow service if your location can be reached in two hours (this could vary by region.)