A few years ago the speed limit was 150km/h for all vehicles, and for TMP and it's congestion in some places it was not really suitable. In some places the limits of 60 and 80 are understandable (like in cities or smaller roads leading to them), but on highways near cities with at least 2 lanes the limit should always be min. 90km/h. Some limits are really ridiculous, take Athens for example.