Const. Ian MacDonald says the roadblock was set up around downed trees after a storm and an SUV sped past an officer before crashing.
He says the occupants escaped before two people in another SUV were seen crouching in their seats as they drove by.
Twenty-nine-year-old driver Brian Stephan and 27-year-old passenger Stephanie Glaister were arrested after the vehicle was stopped with a spike belt.
MacDonald says they are accused of stealing both SUVs and face multiple counts and that charges against Stephan include breach of probation and driving while suspended.
Stephan and Glaister are known to police.