Vehicular communications enable information exchange among vehicles including the roadside infrastructure. This has led to applications to primarily increase road safety and traffic efficiency. Standardization efforts on vehicular communications are underway. The physical layer (PHY) is defined based on the IEEE 802.11 family of WiFi standards operating at the 5.9 GHz frequency band and on extensions of long-term evolution (LTE); in both cases orthogonal frequency division multiplexing (OFDM) is the waveform of choice. Since the typical environment of WiFi deployment is very different to the vehicular communication environment, it is a challenging task to adapt the WiFi-based PHY for providing reliable and real-time communications under highly time- and frequency-selective fading channels. In this paper, the employment of an alternative waveform termed generalized frequency division multiplexing (GFDM) for vehicular communication is investigated. Specifically, a GFDM-based packet design is proposed on the basis of the standard-compliant OFDM-based PHY configuration. On the receiver side, this paper focuses on developing synchronization, channel estimation, and equalization algorithms. The performance of the resulting GFDM-based PHY is verified and compared with the OFDM-based one by means of simulation. The obtained results demonstrate that the proposed GFDM-based PHY can utilize the time and frequency resources more efficiently, and outperform particularly under challenging channel conditions. Additionally, the low out-of-band emission of GFDM is a desirable feature for future multichannel operation (MCO) in vehicular communications.