To avoid the need for transponders, some systems, notably the 407 ETR (Electronic Toll Route) near Toronto and the A282 (M25) Dartford Crossing in the United Kingdom, use automatic number plate recognition. Here, a system of cameras captures images of vehicles passing through tolled areas, and the image of the number plate is extracted and used to identify the vehicle. This allows customers to use the facility without any advance interaction with the toll agency. The disadvantage is that fully automatic recognition has a significant error rate, leading to billing errors and the cost of transaction processing (which requires locating and corresponding with the customer) can be significant. Systems that incorporate a manual review stage have much lower error rates, but require a continuing staffing expense.