TULSA, Oklahoma - Tulsa Police are responding to multiple crashes on Tulsa highways Tuesday afternoon as light precipitation and below-freezing temperatures created slick roads. 

EMSA said between 3 p.m. and 5:40 p.m. it had responded to 19 collisions related to road conditions, and nine of those patients were taken to Tulsa hospitals. 

EMSA aid the incidents were more significant on or around the IDL and the Keystone Expressway, primarily on the on-ramps and elevated surfaces. 

A car slid and overturned on the Sand Springs Expressway in the eastbound lanes close to the northwest side of the IDL. 

Shortly after that, emergency responders were on the scene of a crash at Peoria and Highway 75. That crash involved three vehicles, including an ambulance that was off the highway responding to a car wreck. EMSA said that ambulance had a patient in the back of the ambulance at the time of the crash but that patient wasn't taken to the hospital. But, the driver of the car that rear-ended the ambulance was taken to the hospital with non-life-threatening injuries.

Tulsa police wrote on their Twitter account that it has activated Operation Slick Streets as road conditions continue to deteriorate. 

Police said they'd received multiple reports of wrecks on the Keystone Expressway just west of downtown. 

TPD said to slow down and drivers should allow themselves more time to reach their destinations. 

The National Weather Service expanded the travel advisory north to I-44 corridor to include Tulsa County.

The City of Tulsa said crews pre-treated bridges and hills with brine overnight and into the day.

Rogers State University in both Claremore and Pryor canceled evening classes Tuesday.