A vehicle communications system comprising: a first communications device configured for attachment to a vehicle comprising: a first antenna group comprising at least one antenna, a first receiver circuit configured to receive a first instance of a message via the first antenna group, a decoder that partially decodes the first instance of the message after receipt to create a partially decoded message, an encoder that encodes the partially decoded message to create a second instance of the message, a first transmitter circuit configured to transmit the second instance of the message via the first antenna group, and a first controller configured to cause transmission of the second instance of the message via the first transmitter circuit, in response to the first receiver circuit receiving the first instance of the message; wherein the first controller is further configured to: determine a current congestion of a wireless medium accessible via the first antenna group; and refrain from causing the transmission of the second instance of the message when the current congestion exceeds a threshold; and a second communications device configured for attachment to the vehicle comprising: a second antenna group comprising at least one antenna, a second receiver circuit configured to receive data via the second antenna group, wherein the second receiver circuit receives both the first instance of the message and the second instance of the message, and message combination circuitry configured to generate a combined message by combining the first instance of the message and the second instance of the message. a first communications device configured for attachment to a vehicle comprising: a first antenna group comprising at least one antenna, a first receiver circuit configured to receive a first instance of a message via the first antenna group, a decoder that partially decodes the first instance of the message after receipt to create a partially decoded message, an encoder that encodes the partially decoded message to create a second instance of the message, a first transmitter circuit configured to transmit the second instance of the message via the first antenna group, and a first controller configured to cause transmission of the second instance of the message via the first transmitter circuit, in response to the first receiver circuit receiving the first instance of the message; wherein the first controller is further configured to: determine a current congestion of a wireless medium accessible via the first antenna group; and refrain from causing the transmission of the second instance of the message when the current congestion exceeds a threshold; and a first antenna group comprising at least one antenna, a first receiver circuit configured to receive a first instance of a message via the first antenna group, a decoder that partially decodes the first instance of the message after receipt to create a partially decoded message, an encoder that encodes the partially decoded message to create a second instance of the message, a first transmitter circuit configured to transmit the second instance of the message via the first antenna group, and a first controller configured to cause transmission of the second instance of the message via the first transmitter circuit, in response to the first receiver circuit receiving the first instance of the message; wherein the first controller is further configured to: determine a current congestion of a wireless medium accessible via the first antenna group; and refrain from causing the transmission of the second instance of the message when the current congestion exceeds a threshold; and determine a current congestion of a wireless medium accessible via the first antenna group; and refrain from causing the transmission of the second instance of the message when the current congestion exceeds a threshold; and a second communications device configured for attachment to the vehicle comprising: a second antenna group comprising at least one antenna, a second receiver circuit configured to receive data via the second antenna group, wherein the second receiver circuit receives both the first instance of the message and the second instance of the message, and message combination circuitry configured to generate a combined message by combining the first instance of the message and the second instance of the message. a second antenna group comprising at least one antenna, a second receiver circuit configured to receive data via the second antenna group, wherein the second receiver circuit receives both the first instance of the message and the second instance of the message, and message combination circuitry configured to generate a combined message by combining the first instance of the message and the second instance of the message.