The flooding was most severe near 300 Nguyen Thong Road in Phu Thuy Ward, where fast-flowing water carried large amounts of red sand and mud onto the road.
Nguyen Thong is a major route linking central Phan Thiet with the Mui Ne tourist area and carries heavy traffic.
A thick layer of sand left the road slippery, causing several motorcyclists to lose control and fall.
Local authorities cordoned off the affected section, diverted traffic and helped residents through flooded areas. After the rain eased, excavators were deployed alongside local forces to clear sand and mud from the road.
Residents said the area had experienced similar "red sand floods" during heavy rain in the past.
The same section was repeatedly affected in September 2024, prompting authorities to install drainage pipes and reinforce parts of the area. However, the measures have yet to fully prevent sand from washing down from nearby hills during intense rainfall.
Heavy rain is continuing across Lam Dong Province, raising the risk of flooding, landslides and fast-flowing runoff on roads near hills and mountain passes.