PHOENIX — Motorists hoping to shave a few minutes off that trip across town or across the state now have two new reasons not to do that.

 They come in the form of the first two mobile photo radar van deployed Thursday by the state Department of Public Safety. So anxious was DPS Director Roger Vanderpool to get the vans on the road that they were sent out to begin issuing tickets shortly after the press conference to announce they are now here.

 And this is just the beginning: Vanderpool said if all goes according to plan, his agency eventually will have 20 of these scattered around the state, parked beside not just freeways but two-lane roads controlled by the state.

 But Vanderpool insisted the aim is not to generate revenues — he said the DPS gets just a small percentage of every fine — or even to penalize motorists. Instead, he called it a “tool’’ to help DPS do its job.

 “It’s aimed at getting people to slow down and pay attention,’’ he said.

 In fact, Vanderpool said there’s no reason for drivers who are keeping their eyes on the road to ever get one of thos  citations. That’s because the agency, as required by state law, will be erecting large portable fluorescent orange signs at least 100 yards ahead of the unit informing oncoming traffic that a photo radar van is there.

 “If you’re not paying attention and you miss the signs, smile,’’ Vanderpool said, as you’ll be getting a picture of yourself in the mail, along with the ticket.

 But foreign motorists driving vehicles from their own countries can ignore the vans with impunity.

 That’s because DPS officials acknowledged foreign governments do not share license plate information with them. And that means there’s simply no place to send the citation.

 Vehicle owners who have purchased one of the many license plate covers designed to thwart photo radar cameras may also get away without being cited.

 That, however, may be just temporary: DPS Commander Tom Woodwar said his agency will be experimenting with infrared technology which can “see’’ through many of the plate covers.

 And Vanderpool stressed the photo radar units will not replace DPS patrol officers. Instead, he said, it will free them up t look for — and stop — reckless drivers and those suspected of drunk driving.

 The vans actually will be operated by Redflex Traffic Systems under a contract where the state pays $4,000 a month per unit.

 That covers the vehicle, the staffer and the cost of generating the citations.

 Gov. Janet Napolitano ordered DPS to begin using photo radar earlier this year to enforce the state’s speeding laws. The governor she was convinced by a nine-month project along the 101 freeway — operated by Redflex for the city of Scottsdale — that the stationary photo radar cameras there cut how fast motorists were driving.

 Several legislators subsequently attempted to block photo radar on state roads until the plan could be reviewed by voters but were unable to gain the necessary votes for approval.

 Woodward said the cameras will be programmed to take pictures — and issue citations — any time a vehicle is traveling at least 11 miles per hour over the speed limit.

 Woodward said those whose speed is just six miles over the limit also would have their pictures taken. But he said they would just get warnings, much in the same way a DPS officer might stop and warn a driver.

 “That’s because the goal of this program is to get people to slow down,’’ he said. “It will enable us to impact people’s driving behavior without citations.’’

 Woodward said, though, the drivers who get these warnings won’t be getting a copy of the photo taken by the photo radar van. He said motorists might see that as a “souvenir.’’

 He said the state opted to go with mobile vans instead of fixed units, like the ones in Scottsdale, to make them more effective.

 “One of the concerns about stationary cameras is that they’re in the same place all the time,’’ he said. “People begin to learn where they area.’’