Vehicular communication systems can be used to improve the safety level of road users by exchanging safety/warning messages. In this paper, we propose an antenna for a pedestrian-to-vehicle (P2V) device that provides a safety service to road workers on the highway or the road environment. A metasurface antenna system was fabricated and tested first in a controlled laboratory environment in an anechoic chamber. The device is designed to be worn close to the body of the road worker and in this framework the specific absorption rate (SAR) has to be evaluated and compared to the threshold values recommended by standards. Field tests results in an environment representative of the highway are conducted at the Transpolis test tracks are also provided to validate the performances of our system. It is shown that the proposed antenna system consisting of two monopoles backed by a metasurface reflector is an excellent candidate for P2V communications based on IEEE 802.11p systems with desirable radiation pattern, polarization, and safety limits.