The rapid progresses made in the area of intelligent transportation systems (ITS) call for high rate intra-vehicle wireless communications. Ultra wideband (UWB) and multi-antenna are both promising technologies providing high data rate. This paper evaluates the channel capacity of intra-vehicle single-input multiple-output (SIMO)-UWB using the measured signals in the experiment. The channel measurement is carried out in two vehicles, a sedan Ford Taurus and an SUV GM Escalade, with different transceiver placements, beneath the chassis and inside the engine compartment. Both channel state information available to the transmitter (CSIT) and channel state information available to the receiver (CSIR) cases are involved in our results. The results reveal that the channel capacity remain unchanged although experiment settings changes, including vehicle type, engine status, and transceiver location; and that water filling fails to demonstrate its advantage as the number of receiver antenna increases.