As reported last night, three vehicles were involved in the collision, which was reported to the emergency services at 6.21pm yesterday.
A police spokesman added that her next of kin have been informed, adding that several people remain in hospital and are receiving treatment for their injuries.
The man who was arrested remains in custody this morning.
The police spokesman added: "Officers would like to renew the appeal for any relevant dash cam footage captured by motorists.
"They would particularly like to hear from anyone who witnessed or captured footage of the Mercedes GLA prior to the collision in the Burwell area."