Will Smart Cars Drive on Smart Roads? About Sensor Systems in Asphalt Concrete

Developments in smart and automated driving raise questions about the future requirements of infrastructure. It
is highly likely that advances in transport will require close to real-time information on the condition of roads.
The recent, speedy development of sensors may lead to the development of Smart Roads and in so doing,
provide the necessary real-time data. It is within this context that passive RFID sensors were tested in a series of
experiments to ascertain their suitability to measure asphalt concrete mix temperature during construction and
afterwards during the life of the pavement.
Laboratory tests focused on the proper placement of the sensor in the asphalt concrete layer and
studying the latter’s influence on the sensor. Field experiments focused on the suitability to measure temperature,
traceability, robustness, and accuracy of the technology. The results show that reliable temperature measuring
with passive RFID tags is possible. The sensors are robust, portable, accurate and can be integrated into existing
measuring regimes such as determining asphalt concrete cooling rates during construction. While the cost of
passive RFID sensors is relatively low, the major disadvantage is that they cannot be read automatically, which
is crucial if the information is to be used to follow temperature developments over time or even provide asphalt
concrete temperature information to vehicles in order to warn for extreme road conditions. Ongoing experiments
with fiber optic sensors indicate that there may be other ways to measure temperature and possibly combine this
with performance indicators such as strain.