Drive-by Motor Vehicle Emissions: Immediate Feedback in Reducing Air Pollution

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Organizational Units

Chemistry and Biochemistry


Atmospheric chemistry, Emissions, Pollutants


Using input from the public, a new type of vehicle emissions information system has been developed which utilizes an innovative variable message sign to display individual vehicle emissions information to passing drivers. Called the Smart Sign, the system merged highway messaging and on-road vehicle emissions sensing into a cost-effective public information system. The Smart Sign used a combination of words, colors, and graphics to connect with its audience. During its operational test period the system proved to be a viable technical concept which can be operated dependably and safely in even high traffic areas (in excess of 1000 vehicles per hour). The system was subjected to a wide range of operating conditions including weather extremes (-20 to 100°F, heavy rain, hail, snow) and between May 16, 1996 to May 15, 1997 recorded unattended emissions information of more than 3 million readings from an estimated 250 000 individuals. The ability to operate the system without constant human supervision has created a cost-effective messaging system capable of delivering real-time vehicle emissions information for a long term estimated cost of $60 000/yr or about $0.02 per test and demonstrated the potential for intelligent highways of the future to detect gross polluting vehicles. Using information from a companion license plate reading system a sample of 474 motorists (14% poor, 43% fair, and 43% good) were interviewed by telephone. Seventy-six percent of the weighted population had a favorable impression (5% unfavorable) of the Smart Sign with the majority (61%) expressing its informative nature as the main reason. Eight percent of the total sample planned to do something in response to the sign. Respondents in the “POOR” stratum (31%) were almost twice as likely to respond to the system as those in the “FAIR” stratum (16%) and five times as likely as those in the “GOOD” stratum (6%). Sixteen percent of the poor’s (1.6% of the overall fleet) reported to have already taken corrective action as a result of the Smart Sign. This produces an estimate that more than 4000 voluntary repairs were made as a result of Smart Sign readings during the year.

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Copyright held by the American Chemical Society.

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