vehicle separation

Failure of vehicle separation gear has been the bane of automatic toll collection. And the toughest 'separation' challenge is detecting a towbar, whether the equipment deploys overhead or sidefire lasers or video, or uses in-pavement electromagnetic sensors. They all work fine in detecting the mass of a continuous vehicle, but can have trouble 'seeing' a towbar.

A failure in vehicle separation may, or may not, give the following vehicle a toll-free ride. In a commentary on the controversy in Massachusetts we wrote that an overcharge due to a failure in vehicle separation will lead to an overcharge of the leading vehicle and a toll-free trip for the follower.

Boston Herald recently (8/11) led off a frontpager: "Tens of thousands of Turnpike motorists have been socked with falsely inflated Fast Lane bills because the company that provided their transponders violated its multimillion-dollar contract by failing to inspect the system, a state audit has found. (Fast Lane is the Massachusetts Turnpike's brandname for E-ZPass IAG compatible electronic tolling - editor)