Road pricing has become a common policy tool to address urban transportation problems. Whether through highway tolling or congestion charging, it's a way to ease peak traffic volume, fund infrastructure maintenance and encourage ridepooling. But road pricing has a close cousin that doesn't get as much attention, though it is arguably as important: curb pricing.

It follows the same principle as road pricing: Curb space should be charged for, using technology that can calculate a curb's current occupancy rate, its latent demand and what its market price should be. This would help prevent overcrowding and suboptimal curb use, and, like road pricing, attack the skewed status quo in U.S. cities, where car use is underpriced.

For an example of this status quo, take New York City. Many curbs in residential areas are set aside for free 24-hour parking. This adds to traffic as drivers circle the block looking for open spaces, and is a subsidy for car-owning residents, who are being given the use of prime urban land for free.

Curb pricing makes the philosophical point that such land has value and shouldn't be given away. But it's also a pragmatic step to better mobility and placemaking, because many public and private interests have the potential for more innovative curb uses than free car storage. Here's some I would anticipate in a different system:

Bus lanes: The most intuitive use might be to increase road capacity by running additional travel lanes along curbs. If those lanes were subject to tolls, they could function as an express toll lane. Better yet would be high-occupancy bus lanes that transit agencies and private bus companies use.

Bus shelters: Even if lane mileage dedicated to buses isn't expanded, the bus-riding experience could be improved by using curb space for permanent bus shelters. The best shelters I've seen are large, well-lit structures that have maps, seating and more. They're too big for most sidewalks, but become feasible when curb space is available.

Micro-mobility lanes: Various companies have introduced the sharing-economy concept for bikes, scooters and mopeds. But often they're squelched when trying to operate in cities. Part of the issue is that there's no designated right of way for these modes to use, and they don't mix well with automobiles. Using curb space to install protected micro-mobility lanes would make things safer.

Micro-mobility parking: The other excuse cities use for squelching shared micro-mobility is "litter." Because many services are dockless, their equipment gets scattered along sidewalks, parks and elsewhere. Curbs could be used to store this equipment, and it wouldn't even require using the whole curb. Some industrial-grade storage racks consume the equivalent of one parking space but house dozens of bikes. If a city placed these on every block, it would solve the micro-mobility storage problem without taking many car parking spots.

Dropoff zones: Cities have an increasing problem with double parking due to companies like Uber and FedEx that rely on space for dropoffs. They could alleviate this by designating some curb space as paid dropoff space, charging per minute.

Paid parking: Of course, there's nothing wrong with using curb space for old-fashioned traditional paid parking, by the hour or even the day. Charging for it eradicates the problems that result from making parking free, such as people hogging curb space for permanent car storage.

Carshare parking: Companies like Zipcar and Enterprise CarShare are designed to reduce car ownership altogether. But they have the same problems as other forms of shared mobility: In too many cases, city governments haven't designated anywhere for their vehicles to be stored. A curb pricing program could allow carshare companies to lease a certain amount of curb space for their operations.

Trash dumpsters: This may be New York City-specific, but is worth mentioning. The city has minimal alley space and lots of trash. So on trash pickup days people pile bags on sidewalks, attracting vermin and blocking pedestrians. Dumpsters could be used on those days to store trash, but that requires curb space.

Outdoor dining: This has become a common response to the COVID-19 shutdown: Because cities had less car traffic and restaurants couldn't legally serve indoor patrons, they adjusted by allowing more al fresco curbside dining. Cities could make this permanent post-pandemic.

General street beautification: Above all, better curb management means nicer streets. Space that isn't used for free parking can go for everything from wider sidewalks to more seating, parklets, trees and flower beds. Cities could even use the added space to build elaborate road medians, pushing traffic flow away from sidewalks and pedestrians.

Not all of these uses involve literal free-market pricing of curbs; some involve a city government transferring usage rights based on larger social and environmental goals. But many of the uses could have a market component, from restaurants that lease more café space to bikeshare companies that pay for curbside storage as part of their operating agreements with cities. Municipal governments, using their natural monopoly over curb space, could determine the market value of given curbs and lease them to the highest bidders.

Getting public value out of curb space could be even more ambitious, as described in the 1997 book Curb Rights: A Foundation for Free Enterprise in Urban Transit. Say a private bus company needs curb space to pull over and pick up passengers. So it leases curb space and the adjoining sidewalk, where it builds a bus shelter. Having sunk value into what is traditionally considered public space, it can then operate there or sell it to other bus companies, treating the curb like a tradable commodity.

The biggest challenge to this — and the reason market-based curb management isn't common — is the difficulty of determining the real value of a specific stretch of curb space. Dynamically priced parking meters are a primitive version of this. Companies such as Coord, a New York City-based startup, are taking the idea to another level, using software tools to determine how curbs can be better used. But as Coord's head of policy, Dawn Miller, pointed out in an interview, no company has yet determined the true market value of curbside real estate.

Discovering that value feels like one of the great policy frontiers of 21st-century urban America. In the process of testing new curb uses, city officials can determine which users exist, what they'll bid and what a curbside's intrinsic value is. This can be a step toward using the space to better address cities' needs.

[This article was originally published by Governing.]