When Jacksonville drivers ask how fast mobile charging is, they are really asking two questions: how long until the truck arrives, and how long until the car can drive. Both deserve straight answers, because this is the largest city by land area in the contiguous United States and any service that quotes one flat number is not being honest with you.
Response time tracks the map on the Jacksonville hub. The urban core and the Southside sit closest to the middle of the zone, so San Marco, Riverside, Downtown, and the Town Center corridor land in the 30 to 50 minute band. The Beaches and Arlington add a bridge crossing. The Northside adds distance. St. Augustine adds both.
Two Jacksonville-specific variables matter more than anything else. First, the bridges: a stall on the Buckman or an opening of the Main Street drawbridge reroutes everything near it. Second, events: when EverBank Stadium lets out, the sports complex grid and the Arlington Expressway approaches crawl for an hour. Dispatch accounts for both when quoting your ETA, which is why the quote is live rather than a printed promise.
Once on-site, the session behaves like a fast-charging stall that came to you. The equipment negotiates with your car's battery management system, which sets the rate it will accept based on state of charge and temperature. In practice a Jacksonville emergency session delivers 20 to 80 miles of range in 15 to 45 minutes, enough to reach the Town Center Superchargers, a home charger in St. Johns, or wherever you were headed.
Compare the alternatives from, say, a dead battery on Merrill Road in Arlington. A tow means waiting for the flatbed, riding to a fast charger on the Southside, hoping a stall is open and working, then charging. Limping to a charger you might not reach risks a shutdown on a bridge approach. The truck coming to you turns all of that into one wait, and the emergency service runs 24/7, so the math holds at 2 AM exactly as it does at noon.