Laminar flame speeds of n-decane/air mixtures were determined experimentally over an extensive range of equivalence ratios at 500 K and at atmospheric pressure. The effect of N-2, dilution on the laminar flame speed was also studied at these same conditions. The experiments employed the stagnation jet-wall flame configuration with the flow velocity field determined by particle image velocimetry. Reference laminar flame speeds were obtained using linear extrapolation from low to zero stretch rate. The determined flame speeds are significantly different from those predicted using existing published kinetic models, including a model validated previously against high-temperature data from flow reactor, jet-stirred reactor. shock tube ignition delay, and burner-stabilized flame experiments. A significant update of this model is described that continues to predict the earlier validation experiments as well as the newly acquired laminar flame speed data and other recently published shock-tube ignition delay measurements.