A sign warns drivers not to speed during certain hours in a school zone on Esplanade Avenue in New Orleans, Tuesday, April 2, 2019. People were surprised with speed tickets after New Orleans officials lowered the speeds that trigger traffic camera tickets without informing the public.

Months before Mayor LaToya Cantrell’s administration trimmed the excessive speed that triggers New Orleans' traffic cameras last month, officials determined that doing so could result in tens of thousands of additional tickets worth up to $7.5 million a year to the city.

The analysis, obtained by The Advocate through a public records request, was intended to “estimate the additional revenue that would be generated in a year” by reducing the speeding threshold for tickets.

The report was presented to city officials in December, two months before the thresholds were changed. The administration announced in November that it would be getting rid of some of the city’s lucrative cameras but keeping those in school zones.

City officials have been taking heat in recent days for the changes to the speed thresholds, which were dropped on Feb. 4 from 26 mph to 24 mph in school zones and from 10 mph over the speed limit to 8 mph over elsewhere.

The higher thresholds had been officially acknowledged by former Mayor Mitch Landrieu’s administration, but Cantrell’s administration did not warn motorists of the change, leaving many to find out when they received tickets in the mail.

The Cantrell administration has defended the reduction as a way to improve safety in the city. But the fact the financial analysis was done suggests the money the city was bringing in from the cameras was a top concern.

A similar analysis was not put together to analyze whether tightening the rules on traffic cameras would increase safety, according to Cantrell spokesman Beau Tidwell, though he pointed to other studies showing faster cars cause more serious injuries.

“This analysis was used to determine how many drivers would be impacted by the proposed change,” Tidwell said in an email. “It was one of several factors considered, including knowledge of external studies that closely link vehicle speeds and fatality rates.”

According to the analysis, the cut in speeds would yield between $5.7 million and $7.5 million in new revenue a year from between 76,000 and 100,000 new tickets in school zones. At the high end, that would increase the $25 million the camera program was projected to bring in this year by almost a third.

If the city hit those revenue figures, it would also more than make up for the money it lost when Cantrell agreed to scrap about 20 cameras outside of school zones. Removing those cameras, which followed on a campaign pledge by the mayor to eliminate the whole traffic camera program, was expected to cost the city about $4 million a year.

The analysis did not take into account mobile cameras or remaining cameras outside school zones, all of which mean more revenue for the city.

On Tuesday, reported that data it obtained on school zone tickets showed that 51,170 camera citations were issued in February, a 79 percent increase over January.

The December analysis was based on a database of all vehicles clocked driving more than 20 mph in school zones last September and October.

The analysis calculated how many of those drivers would be ticketed if the trigger was reduced to various speeds ranging from 21 mph to 25 mph. Those figures were then adjusted based on the rate at which tickets are found to be valid and then further reduced to account for the roughly 48 percent of violations that are never paid.

Ticketing anyone who creeps over the 20 mph limit could potentially yield a windfall of roughly $40 million a year, according to the report. On the other hand, reducing the threshold by only 1 mph would have brought in only a bit more than $2 million.

It’s not clear how well the analysis would play out in reality. The report assumes no changes in driver behavior or traffic volume, though motorists typically learn quickly to slow down or avoid locations with speed cameras.

City officials had originally considered including a warning about the change in a press release about some traffic cameras' removal in early January, but it ended up scrapping that language. As a result, for about two months drivers were being ticketed without any official warning about the need to change their habits.

New Orleans nearly warned drivers before changing speed camera rules; here's what we know

City officials recognized there would likely be a change in driver behavior due to the new thresholds, but they were not able to quantify it, Tidwell said.

State Sen. Troy Carter, a New Orleans Democrat who has been critical of the traffic camera program in the past, said he had concerns about using cameras to bring in cash rather than deploying them to improve safety.

Last year, he sponsored a bill that would have required all governments in the state to give a pass to drivers caught by cameras while traveling less than 9 mph over the limit, but he withdrew it when assured that the thresholds across the state were already at least that high, he said.

“Ratcheting them down in school zones to 4 mph, if it’s for public safety I could support that,” Carter said. “What I can’t support is if we’re only doing it for money. I think we send the wrong message to the electorate if we say in any way we’re doing this to increase revenues; it should purely be done for public safety.”

Although a safety study was not conducted, Tidwell said there is “a significant amount of existing literature on this subject and many studies ... find very strong relationships between vehicle speed and fatality rates.”

However, the reports show only a small difference between the fatality rates at the old trigger of 26 mph, which one report found gives a pedestrian a 13% chance of being killed, and the new threshold of 24 mph, where the fatality rate is 11%.

Follow Jeff Adelson on Twitter, @jadelson.​