When it comes to HD maps, there are different types of accuracy to be considered – and several different factors that can contribute to errors.
The short answer to this question is that we achieve a local/map relative accuracy of 5cm or below for objects within a 10m corridor of the drivable route.
Global/absolute accuracy is determined by GNSS/GPS, which cannot be bound. Conditions sometimes vary quite a lot, particularly in areas with poor satellite reception (e. g. urban canyons or tunnels), so this number needs to be taken with a grain of salt: For areas where the GNSS quality is good and proper base station correction data available, the global accuracy will deviate by an additional 3cm or below.
For a more detailed answer, information on how we achieve this accuracy, and how we mitigate errors in GNSS-denied areas please give our article “How Accurate Are HD Maps for Autonomous Driving and ADAS Simulation?” a read.