Updated at 7:45 p.m.

Making it easier for people to pay for street parking has been a win for Minneapolis' coffers.

Data from the city's public works department show that since the implementation of credit card parking payment began in 2010, net profits have nearly doubled from $4.7 million to $8.6 million in 2014.

My colleague Kelly Smith requested the information for her Sunday story on parking around Lake Minnetonka, though it did not make it into the final draft.

Revenues have been tempered somewhat by rising expenses due to credit card fees, however. The figures also do not account for ticket revenues, which have declined in the past three years.

Other factors impacting revenues include the ability to vary meter rates for events, adding more meters and payments from carsharing companies, said Jon Wertjes, the city's director of traffic and parking services.

The money is funneled into the city's municipal parking fund, which largely pays for operations and debt service on city-owned parking ramps. The rest was expected to go to the general fund ($4.1 million) and Target Center ($3.5 million) in the 2015 budget.

While the implementation of credit card machines began in 2010, it wasn't complete until November 2012 at a cost of about $7.3 million. Most of the city’s meters now consist of poles with numbers that drivers enter into solar-powered multi-space payment machines nearby. 

Those machines also accept coins, but credit card users spend more on average. A city report found that while credit cards comprised 57 percent of transactions at the new machines in the last quarter of 2012, they accounted for nearly 75 percent of the meter revenue.

In most areas of the city, the hourly rate falls somewhere between $.50 and $2. On Vikings game days, rates around the former Metrodome site skyrocket to $15 an hour. Twins games bring more modest increases to the North Loop and Farmers Market areas, which typically offer some of the cheapest street parking in town.

The next innovation in on-street parking is expected to come this May, when the city begins its roll-out of a pay-by-phone parking option. The city will start by offering the service at 500 meters, gradually expanding the rollout through the fall.

St. Paul also converted many of its machines to accept credit cards in 2012, though some older machines remain, according to city spokeswoman Sara Thatcher.

The city — which has far fewer meters than Minneapolis — saw revenues rise from about $1.5 million in 2011 to $2.2 million last year. The precise profits after expenses were not immediately available Monday afternoon.

Other factors may have played a role in the increase, since St. Paul also raised parking rates and expanded enforcement hours in late 2012.