This paper shows an in-vehicle radio communications using ultra-wideband (UWB) signals. Based on simulations results considering in-vehicle radio propagation characteristics (path gain and delay spread) obtained by measurement, turbo-coded 8-ary pulse position modulation (8PPM) is employed as transmission scheme. Experiment in an anechoic chamber has been conducted in order to demonstrate the transmission scheme with actual vehicles. It is confirmed that the obtained results in experiment agree with the simulation results.