Police were called to the scene, near the Wat Naka temple, at 2am.
They arrived to find rescue workers using hydraulic cutters to recover Mr Santi, unconscious and unresponsive, from his wrecked Mercedes-Benz, which had slammed into the back of a six-wheeled truck.
Mr Santi was taken to Vachira Phuket Hospital in Phuket Town, where he was pronounced dead on arrival.
Police suspect Mr Santi, 50, fell asleep while driving.
“His body was taken to Vachira Hospital for doctors there to confirm the cause of death,” said Lt Patcharee Wongboon of the Wichit Police.
“ Mr Santi was heading toward his home in Chalong. He probably fell asleep when he was about to make a left turn onto Chao Fa West Rd when his car struck the back of the truck,” she said.
“We are not sure if the truck had stopped at a red light or if it was slowing down to turn at the junction, but the driver, 26-year-old Wanlop Thongked, was taken in for questioning,” Lt Patcharee said.
The Russian Consulate in Phuket is aware of the accident. The Phuket News has been informed that the consulate will likely release a statement later today.
Mr Santi served as a Deputy Honorary Consul of the Russian Federation in Phuket, Phang Nga and Krabi provinces since 2008, reported the Bangkok Post (see story here.)