Transportation monitoring system for detecting the approach of a specific vehicle

A means for alerting a person to a proximity of a transmitter at a first instant of time, comprising:

• a transmitter and a receiver spatially disparate to said transmitter, said transmitter and receiver tuned to a common transmission signal;
• a threshold of said common transmission signal detectable by said receiver;
• a code carried by said common transmission signal identifying said transmitter and detectable by said receiver;
• a means within said receiver for comparing said code to a plurality of stored values and responsive to a match therewith generating a signal indicative of a match;
• and
• a means to prevent at least one of said plurality of stored values from being included in said match signal generating.

A system for detecting the approach of a vehicle, comprising:

• a vehicle transmitter which operatively transmits at least one code beyond said vehicle transmitter;
• a code generator that generates a representative code selected from a plurality of codes which is representative of and uniquely identifies said vehicle transmitter and is discernable from others of said plurality of codes, said code generator operatively coupled to said vehicle transmitter to couple said representative code to said vehicle transmitter for transmission of a Manchester coded signal therefrom;
• a receiver remote from said vehicle transmitter having a signal receiver operatively monitoring transmitted signals from said vehicle transmitter at a signal strength at said receiver of at least a first threshold and having a code demodulator responsive to said signal receiver extracting said representative code from said signal;
• and
• a code detector comparing said representative code to a plurality of user-selected codes and generating an indication of identity with any of said plurality of user-selected codes;
• and
• a lock-out for preventing said indication of identity with at least one of said plurality of user-selected codes for a first time interval.