When the road was upgraded, the route was changed to bypass the section from Kyubeme to Kadykchan via Tomtor, and instead pass from Kyubeme to Kadykchan via a more northern route through the town of Ust-Nera. The old 420 km section via Tomtor was largely unmaintained; the 200 km section between Tomtor and Kadykchan was completely abandoned.[6] This section is known as the Old Summer Road, and has fallen into disrepair, with washed-out bridges and sections of road reclaimed by streams in summer. During winter, frozen rivers may assist river crossings. Old Summer Road remains one of the great challenges for adventuring motorcyclists and 4WDers.