PORT ANGELES — A four-car chain reaction collision sent two people to Olympic Medical Center with neck injuries and tied up traffic on U.S. Highway 101 in front of Wal-Mart for about 30 minutes on Thursday afternoon.

According to Washington State Patrol, four vehicles were stopped eastbound on Highway 101 at East Kolonels Way.

According to State Patrol, a 2001 Isuzu Rodeo driven by Naomi L. Riggins, 51, of Port Angeles was the last car in a row of four idling vehicles.

Riggins is the manager for PenCom, the 9-1-1 emergency dispatch center that handles dispatching duties for law enforcement agencies throughout Clallam County.

Riggins apparently took her foot off the Rodeo’s brake, which allowed her car to roll into the back of a 2001 Mazda 626 driven by 83-year-old Sequim resident Edna Bolinger.

When she realized her mistake, State Patrol said, Riggins stepped on the accelerator instead of the brake, pushing Bolinger’s Mazda into the back of a 2000 Mercury Villager driven by 65-year-old Port Angeles resident Charles Hahn, which in turn pushed Hahn’s minivan into the back of a 2002 Dodge Caravan driven by 67-year-old Forks resident Berit Cole.

The collision tied up the left eastbound lane of U.S. Highway 101 for about 30 minutes beginning at 3:29 p.m., said State Patrol spokesman Brian George.

Edna Bolinger and her passenger, Parker Bolinger, also 83 of Sequim, were transported to Olympic Medical Center for neck injuries.

The Bolingers were treated in the emergency room, but not admitted, a hospital spokeswoman said Thursday.

Hahn was treated for neck and back injuries at the scene.

Riggins and Cole were not injured, State Patrol said.