What the Route 66 means to U.S., the road 409 means to Slovenians. Before the A1 motorway was built this was “The Road” most Slovenians used to travel to the coast for their summer vacation. Perhaps that’s why it grew so close to our hearts, but I suggest you take it as the A1 alternative simply because the road is well maintained, with nice scenery, and sparse traffic. It offers plenty of opportunities to switch to A1 in case you accidentally caught a glimpse of the clock.
