SAFE STRIP has developed an On-Road Unit (ORU) which includes all the hardware systems installed on the road, necessary to acquire data from the sensors and to transmit data to the passing vehicles. More specifically, it consists of on-road sensors (e.g. humidity, ambient light detector, temperature, etc.), of a communication module and of an energy management and harvesting system that is responsible for the sustainability of the system. The ORU is shielded by an encapsulation package which protects all the electronic components, batteries, sensors and antennas from vehicle load, temperature extremes, corrosive agents (gas, oil) and water. SWARCO’s cold plastic material will be applied on top of the ORU to ensure safety and tire traction. The integration of the various sensors into the infrastructure will be invisible to the road users, as a grey asphalt colour has been chosen to cover the encapsulation package.
Figure 1: Sample of SAFE STRIP encapsulation package and SWARCO’s material
The combination of the encapsulation material with the cold plastic material has been recently tested at SWARCO labs. In particular, chemical resistance, adhesion and abrasion resistance have been tested to evaluate fulfilment of standard requirements. The chemical resistance test showed that a very good chemical resistance can be assumed between the materials, with no impact on the materials properties. The pull-off test for adhesion highlighted a very high adhesion of the encapsulation with primer and top coat of the material.
Finally, the wheel wear simulator test was only partially performed, due to the very high thickness of the encapsulation material. The system was tested with limited 1000 wheel passing. However, it showed that SAFE STRIP can handle the load of the passing wheels and that the adhesion is enough. These tests have been successful, and the combination of encapsulation material and grey cold plastic material showed excellent performance in all laboratory tests. It is expected that the material will fulfill all requirements regarding adhesion, abrasion resistance and persistence under real-traffic conditions. SAFE STRIP system will be soon applied at the project’s test fields for on road validation.
