  We consider a one dimensional ballistic random walk evolving in a parametric
independent and identically distributed random environment. We study the
asymptotic properties of the maximum likelihood estimator of the parameter
based on a single observation of the path till the time it reaches a distant
site. We prove an asymptotic normality result for this consistent estimator as
the distant site tends to infinity and establish that it achieves the
Cram\'er-Rao bound. We also explore in a simulation setting the numerical
behaviour of asymptotic confidence regions for the parameter value.
