Flags will fly at half-staff Friday for fallen Colorado State Trooper Cody Donahue, who was killed a week ago when a truck hit him.

Donahue was working the scene of an earlier accident on Interstate 25 near Castle Rock. Deputies say the truck driver didn’t move over – and crossed the yellow lines and went into the shoulder, hitting Donahue.

Thursday, state troopers, deputies and police officers are out looking specifically for drivers ignoring Colorado’s “Move Over” law.

This requires drivers to move over at least one lane when approaching emergency vehicles with their lights on. If that’s not possible, drivers need to slow down dramatically.

9NEWS sat down with CSP and the Castle Rock Fire Department for a refresher course on the rules of the road, and to learn what we can do to make our first responders safer.

One thing they touched on was making sure driving has your full attention.

“I think there was a time when multitasking is doing two things at the same time, and now, technology gives us the opportunity to do lots of things at the same time,” Chief Art Morales with the Castle Rock Fire Department said. “Really, driving is a singular activity. You need to pay attention, and operate the vehicle.”

Trooper Josh Lewis with Colorado State Patrol wants to remind people that laws are there for a reason.

“It’s actually Colorado law,” Lewis said. “If you see an emergency vehicle such as the fire department or police vehicle, as well as maintenance crews and they have the lights illuminated, you’re required to move over at least one lane. If you are unable to do so, slow down significantly. That does not mean slow down to the speed limit – it means slow down significantly.”

He wants to remind people that first responders are people – and they also have families they want to go home to.

Morales suggests using the five-second rule. This means keeping a distance of five seconds behind the car in front of you, which gives you time to react and break in time.

To do this, pick a spot up ahead and count to five. That’s the distance you’re shooting for. But remember: The faster you’re going, the more space will be required.

This information and more will be shared in a PSA that will run in 13 Colorado movie theaters. At 11 of those theaters, there will also be a large cardboard display to continue to drive the message home.

You can see the PSA at the following locations:

Bel Mar 16 with XD 440 S TELLER ST LAKEWOOD CO 80226
Bowles Crossing 12 8035 W BOWLES AVE LITTLETON CO 80123
*Cherry Creek 8 3000 E 1ST AVE DENVER CO 80206
Cinema Latino Aurora 777 PEORIA ST AURORA CO 80011
Cinema Saver 6 2525 WORTHINGTON AVE FORT COLLINS CO 80526
Colorado Center 9 with IMAX 2000 S COLORADO BLVD UNIT D DENVER CO 80222
Colorado Mills Stadium 16 with IMAX 14500 W COLFAX AVE LAKEWOOD CO 80401
Greenwood Plaza 12 8141 E ARAPAHOE RD GREENWOOD VILLAGE CO 80112
Meadows 12 9355 PARK MEADOWS DR LONE TREE CO 80124
Regal River Point 3565 S PLATTE RIVER DR ENGLEWOOD CO 80110
*South Glen Stadium 14 6901 S VINE ST CENTENNIAL CO 80122
West Village Stadium 12 14225 W COLFAX AVE LAKEWOOD CO 80401
Canyon View Stadium 14 648 MARKET ST GRAND JUNCTION CO 81505