Two years in a row, showdowns in state government have centered on the use of red-light or photo-radar speed cameras to police traffic, which rakes in serious money in the process. And two years in a row, Gov. John Hickenlooper, Denver’s former mayor, has used his veto pen to protect cities’ ability to use the devices.

Now that the dust has cleared, Denver is getting ready to ink a new five-year contract with its photo-enforcement vendor that could lead to expansions of the programs that catch red-light runners and speeders in the act.

The Denver Police Department says any expansion probably would be measured and isn’t yet assured. DPD, which has red-light cameras at four central Denver intersections and sends out up to four photo-radar speed vans each shift, doesn’t appear to aspire to match cities such as Chicago or Washington, which have installed cameras at dozens and dozens of intersections.

But some City Council members are eager to see more cameras installed at crash-prone intersections or more photo-radar units available for setup along speeding-prone neighborhood streets.

The red-light tickets cost $40 for stopping past the white line and $75 for blowing through the light, while speeding costs $40 or $80 (if it occurs in a school or construction zone).

“This is not something that, for me, is a political or philosophical issue, in terms of violation of privacy or something like that,” Councilman Paul Lopez said during a committee meeting last week. “When you’re in the public realm, you have a responsibility for the safety of others.”

Philosophical debates — and skepticism about whether the cameras truly improve safety, as city officials say, or merely the bottom line — are exactly what state legislators have had. Some Democrats have sided with Republicans who see them as government overreach.

“Red light cameras do not warn people,” unlike signs posted far ahead of speed vans, said Sen. Lucía Guzmán, a Denver Democrat who voted to ban them this year. “Therefore, the camera is there to get you — it’s a ‘gotcha.’ … It just seems to go against the grain of safety to me.”

The lawmakers have bristled at how much cities such as Boulder, Pueblo, Aurora and other Denver suburbs take in from photo enforcement.

Denver’s figures show the city collected $43.7 million from 2010 to 2015 — $36.4 million from photo-speed citations and $7.3 million from the red-light camera program, all pouring into the city’s general fund. The programs cost DPD $2.6 million to run last year.

As Denver police and public works officials consider expansion of red-light cameras, they are proceeding cautiously.

“We’re not just going to start putting them up all over the place,” Cmdr. Patrick Phelan said in an interview, adding that more analysis of traffic and crash data is needed. “It’s a tool we like to use, along with engineering and education, to solve problems at intersections.”

Officials portray the cameras as a vital tool in the city’s efforts to increase pedestrian and bicycle safety through its Vision Zero initiative, which calls for reducing fatal crashes each year.

In the council, members including Jolon Clark laud DPD in responding to residents’ speeding complaints along problem stretches by sending out vans.

DPD says it has identified 808 locations that would qualify for speed cameras under state law, which allows photo radar in school and construction zones, near parks and on residential streets with a speed limit of 35 mph or below. DPD has sent the vans to about 150 of them, some more often the others. (Eastbound First Avenue before it turns into Speer Boulevard is popular.)

The full council will hash out the sometimes-contentious use of the cameras when it votes on the new contract with Xerox State and Local Solutions as soon as Sept. 19. That company has provided Denver’s equipment and mailed out citations going back to 2008.

Not all members are necessarily sold. Kevin Flynn, who cast the sole committee vote against advancing the contract, voiced concern that yellow lights at the four intersections with red-light cameras weren’t long enough to account for the speeds people actually drive, as one national standard advocates.

“If we make this commitment and stop giving $75 tickets to people driving normally,” he said, “then I can support this.”

Photo enforcement unit supervisor Ted Porras said his observation has shown that changes in yellow-light timing typically result in an initial reduction in drivers running red lights, but the violations rise again as people become used to the new intervals.

The city had extended Xerox’s contracts on a short-term basis while legislators debated potential changes. Beginning in August 2015, DPD sought bids for a combined contract and considered five companies, Phelan said, ultimately scoring Xerox’s proposal highest this year.

The proposed $6.4 million contract would last through September 2021. It includes technology upgrades intended to improve accuracy and photo resolution while making the red-light camera setups more portable, Phelan said, although a draft of the contract had not yet been filed with the council.

Xerox would provide new mobile speed units that are outfitted police cruisers, replacing the vans now run by operators in DPD’s speed unit. The vendor also would be responsible for a public education campaign to increase drivers’ awareness of photo enforcement, he said.

Adding a new red-light camera intersection would cost the city $30,000 to $40,000, Phelan said, but he and others say traffic engineers typically look at other options to improve safety first, such as adjusting light timing or design.

This time, as DPD officials have briefed the council, they have addressed questions surrounding past contracts by putting pointed emphasis on the safety impact of the cameras.

Porras presented the council committee with research showing a clear safety improvement at the four intersection approaches with red-light cameras. At the same time, he showed video clips of recurring T-bone crashes at those intersections, although crashes have fallen by nearly half on the approaches with cameras since their installation in 2008.

Citations at the four intersections have dropped consistently each year, with overall decreases ranging from 6 percent to 61 percent. The cameras monitor eastbound Sixth Avenue at Kalamath Street, eastbound Sixth at Lincoln Street, westbound Eighth Avenue at Speer Boulevard and northbound Quebec Street at 36th Avenue.

The picture isn’t as consistent for the photo-radar vans, perhaps because they move around more. But Porras’ data shows speeding has become less frequent in recurring stakeout spots, including along First Avenue and in school zones.

It’s still not clear whether legislators will take another stab next year after this year’s bill to outlaw red-light cameras was met with a veto.

Hickenlooper has said he would support a law that restricts red-light cameras to intersections in school and construction zones as well as those with high traffic volume that are especially prone to crashes.

In the meantime, Rep. Alec Garnett, a Denver Democrat who opposed this year’s bill to outlaw red-light cameras, said Denver residents seem “comfortable with the balance that Denver has currently struck.”

But he cautioned: “I would hope that there would be a robust public process if they were to expand.”