Road authorities need tools to assess potential impacts on traffic performance due to the introduction of automated vehicles. Extended traffic modelling tools offer possibilities to estimate impacts on traffic performance metrics such as travel time, delay and capacity. However, there are large uncertainties related to the future behavior of automated vehicles, and these need to be carefully handled. The aim of this paper is to present a systematic and sound approach that can be used by road authorities to assess the automation readiness of a specific infrastructure. We present a definition of automation readiness from a traffic performance point of view, and an approach for how to estimate the automation readiness for a specific road design taking the uncertainties in the development of automated vehicles into account. The developed approach is applied to both macroscopic and microscopic use cases, demonstrating the applicability of the approach for automation readiness assessment.