The first accident happened early on Saturday morning along the Tampines Expressway.

Miss Siti Hajjar Yaakub, 19, was riding pillion on a motorbike ridden by a 22-year-old National Serviceman along Pan Island Expressway when it skidded at about 1.25 am.

She was flung off the bike before it burst into flames. The motorcyclist suffered fractures to his lower limbs and was taken to Tan Tock Seng Hospital by an ambulance.

Miss Siti, who sustained serious head injuries, died before Singapore Civil Defence Force parademics arrived at the scene.

At around the same time on Sunday, a 29-year-old motorcyclist died after he was thrown off his vehicle at a slip road on Clementi Avenue 6.

The motorcycle was travelling on the PIE towards Changi Airport when it skidded, throwing Mr Muhammad Faizal Abdul Kasim and his pillon rider off. Mr Muhammad Faizal died shortly after at the scene.

His pillon rider fractured his right arm and had abrasions on his body. He was taken to the National University Hospital.