Motorists head north on US 1, Wednesday, Sept. 6, 2017, in Key Largo, Fla., in anticipation of Hurricane Irma. Keys officials announced a mandatory evacuation Wednesday for visitors, with residents being told to leave the next day. (AP Photo/Alan Diaz)

The threat of Hurricane Irma is prompted a mass evacuation of the Florida Keys Wednesday, and state officials say they are not taking any chances, urging residents and visitors in South Florida to be ready to evacuate as the storm moves closer in the next couple of days.

“Do not sit and wait for this storm to come,” Florida Gov. Rick Scott (R) said in a tweet. “Remember, we can rebuild your home–not your life.”

Transportation crews on Wednesday were “aggressively clearing evacuation routes,” officials said, moving construction equipment, barriers and signs from many highway projects and city streets.  As officials rushed to prepare for Irma, construction had been suspended on all state road projects and tolls had been waived.

Scott said the suspension of all tolls in the state would help keep traffic flowing, and make it easier for residents and visitors to evacuate safely and quickly.  The governor declared a state of emergency in all 67 counties to give local governments “ample time, resources and flexibility” to prepare for the storm.

Tolls will remain suspended “for the duration of the storm’s impacts to Florida,” Scott said.

State transportation and emergency officials urged residents to fill up their vehicles’ gas tanks, get familiar with local and state evacuation routes, and have a plan on where to stay during the storm. Heavy traffic is expected as Florida residents in the storm’s path flee to safety.

The city of Key West had ordered mandatory evacuation to tourists starting Wednesday morning, followed by residents’ evacuation Wednesday night.

About 1,000 National Guard troops were on duty Wednesday and an additional 6,000 on standby in Florida, Scott said.

By mid-day Wednesday traffic backups were reported heading north out of the Keys. And there were reports of long lines at gas stations across South Florida, with some stations running out of gas.