According to the Chicago Tribune, ParqEx said investors in the round include Venture Management and Wisconsin Investment Partners, both based in Madison, Wis., where ParqEx formally expanded its service earlier this month. It also said it received funding from participating in two accelerators, $90,000 from Gener8tor in Milwaukee, and $20,000 from Elmspring in Chicago.

Founder Vivek Mehra, who serves as ParqEx's CEO and CTO, said he wants people to see his company as an 'Airbnb for parking.'

Unlike other Chicago-based parking-booking services ParkWhiz and SpotHero - which let people prepay for spots in commercial lots and garages, often at a discount - Mehra said his service focuses on private parking spaces.

SpotHero moved into private spots in 2015 by acquiring ParkPlease, a San Francisco-based platform that let residents rent out their parking spots. It integrated ParkPlease's sellers and customers onto its platform and shut ParkPlease down after the acquisition.

Mehra said he started ParqEx to help drivers park closer to their destinations and to help people make money by renting out the parking spots they own. Many of these spots are in protected areas, such as the parking garage of a condo building.

'What we learned is that although that was a great idea, one of the biggest challenges we were facing was a lot of these parking spaces were locked up behind gates and garage doors,' he said.

Earlier this year, ParqEx introduced technology that lets parking spot renters open the door to a parking garage using the app. Mehra said building ownership must approve installation of special hardware that lets the app control the garage door.

He acknowledged that residents or building management may not like the idea of strangers parking in their lot. It's a problem Airbnb has faced in some condo buildings as well. But Mehra said ParqEx validates the identity of its parkers, and can require them to provide information or to fill out a lease application, if the building requests it. Mehra said this makes using ParqEx more secure than other sites owners might use to list their parking spaces, including Craigslist.

Mehra said ParqEx focuses more on long-term rentals, in part because it gives parkers access to private property, where owners may prefer to keep track of fewer strangers using the facility.

He said more than 60 percent of ParqEx's revenue comes from people who book spots monthly. Some parking spot owners list their spots only during work hours, when their spots lie empty, or nights and weekends. He said the app, which is available for free on iOS and Android, currently has 9,200 active users. A company spokeswoman said ParqEx currently has about 600 spots for rent.

It's free to list parking spots on ParqEx. The company takes a 20 percent commission on every booking, and the renter pays a $1 fee per transaction on top of the spot's cost, Mehra said.

ParqEx has eight full-time employees in Chicago and nine contractors in other cities, Mehra said. He said the funding will support hiring and further expansion.

Andrea Dlugos, co-manager at Wisconsin Investment Partners, said her firm hasn't previously invested in the parking market but that she thought Mehra presented an 'exciting opportunity.'

'A lot (of companies) do seem to be focused on existing commercial parking availability,' Dlugos said. But she said ParqEx is 'uncovering other parking that wouldn't otherwise exist.'