  Estimates are obtained for the Lebesgue constants associated with the Gauss
quadrature points on $(-1, +1)$ augmented by the point $-1$ and with the Radau
quadrature points on either $(-1, +1]$ or $[-1, +1)$. It is shown that the
Lebesgue constants are $O(\sqrt{N})$, where $N$ is the number of quadrature
points. These point sets arise in the estimation of the residual associated
with recently developed orthogonal collocation schemes for optimal control
problems. For problems with smooth solutions, the estimates for the Lebesgue
constants can imply an exponential decay of the residual in the collocated
problem as a function of the number of quadrature points.
