CHARLOTTE, N.C. -- Police are investigating a crash involving three vehicles that caused serious delays Monday morning in northwest Charlotte.

The initial crash occurred around 3 a.m. when a car was rear-ended on WT Harris Boulevard and Technology Drive.

Immediately after the first wreck, some occupants of the vehicles got out while other stayed inside the cars. Then, authorities said a third vehicle came to the intersection and rear-ended the vehicle that caused the first accident.

Three people were transported by Medic to the hospital. One was listed in critical condition.

Alcohol is believed to be a factor in both collision, Charlotte-Mecklenburg Police said. Officers were investigating following the incident.