05485520 is referenced by 252 patents and cites 11 patents.

One or more roadside collection stations (RCS) communicate over a short-range, high speed bidirectional microwave communication link with one or more in-vehicle units (IVU) associated with one or more respectively corresponding vehicles in one or more traffic lanes of a highway. At least two up-link (IVU to RCS) communication sessions and at least one downlink (RCS to IVU) communication session are transacted in real time during the limited duration of an RCS communication footprint as the vehicle travels along its lane past a highway toll plaza. Especially efficient data formatting and processing is utilized so as to permit, during this brief interval, computation of the requisite toll amount and a fully verified and cryptographically secured (preferably anonymous) debiting of a smart card containing electronic money. Preferably an untraceable electronic check is communicated in a cryptographically sealed envelope with opener. Transaction linkage data is utilized in each phase of the complete toll payment transaction to facilitate simultaneous multi-lane RCS/IVU operation. A plaza computer local area network and downlink plaza controller is also used to facilitate simultaneous multi-lane transactions.

Title
Automatic real-time highway toll collection from moving vehicles
Application Number
8/132984
Publication Number
5485520
Application Date
October 7, 1993
Publication Date
January 16, 1996
Inventor
Peter L Hendrick
Jupiter
FL, US
David Chaum
Sherman Oaks
CA, US
Agent
Nixon & Vanderhye
Assignee
Amtech Corporation
TX, US
IPC
H04L 9/00
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