Once just a place for parking near your destination, today’s urban curbs have become a lively, non-stop interaction of countless modes of transportation, from cars, delivery trucks and ride-hail app vehicles to bicycles, e-scooters and pedestrians. Cities are exploring new methods of gathering, exchanging, and interpreting data to set regulations that manage curbside demand and make efficient use of space.

Why Everyone Wants a Piece of the Curb

There are many factors that make curbside space a more precious commodity than ever:

1. More modes are competing for it. Cars, trucks, and taxis have long vied for those nearby parking spots and pick-up/drop-off zones, but curbside management today is a more complicated, dynamic, and debated story than ever. Shared mobility options like e-scooters and bikes add new types of movement to curbsides. And increasing urbanization means more people are using these modes. The UN projects that 68% of the world’s population will live in urban areas by 2050, so the volume of network users will continue to increase.

2. The e-commerce boom has exponentially increased the number of delivery vehicles. “The growth in e-commerce is fueling a commensurate rise in the number of delivery vehicles – box trucks, smaller vans, and cars alike – on city streets,” says CityLab. The National Capital Region Transportation Planning Board estimates that on average, every person in the U.S. generates demand for roughly 60 tons of freight each year. Although you can order everything from TVs to groceries with one click on Amazon Prime, the world outside your door still experiences impacts, and they are felt keenly on the curb.

3. Ride-hail apps… period. While ride-hail app companies (also known as Transportation Network Companies, or TNCs) provide more transportation options, the sheer volume of TNCs and their erratic interactions with the curb bring a new set of challenges. Uber and Lyft usage can mean a lower parking demand, and thus the possibility to reimagine curbside space, but we need to account for their high demand of pick-up and drop-off spaces needed, especially as we look ahead to a future of more automated TNCs and the regulations they’ll need to follow.

Curbside Management on Urban Streets

Curbside management today is a more complicated, dynamic, and debated story than ever.

Curbside management today is a more complicated, dynamic, and debated story than ever.


What’s the Value of the Curb?

“Curbside management exists at the nexus of transportation, land use, and economic development,” writes ITE in the Curbside Management Practitioners Guide. Every city is staring at the question of how to make curbs – a limited resource meeting a seemingly infinite range of needs – more efficient and productive.

We know that curbside space is valuable. The question is, “How do we quantify this value so we can make fair and objective decisions?” A study released by Uber cites a new metric, the “curb productivity index,” which seeks to determine the value of the curb in terms of passenger throughput for each curb use (i.e. number of passengers served per hour per 20 feet of curb). Consensus on measures like this one will be important for establishing decision-making criteria.

Understanding the unique needs of each corridor is fundamental for determining the best value of each space and how to designate use. The way we use the curb in every corridor has important implications for the rest of the network. No street operates in isolation, so along with determining strategies to manage curbs, cities should seek to understand how curbs can manage network demand.

Recent Innovations to Hit the Curb

Curbside management presents an opportunity to advance broader transportation goals, including enhanced safety for pedestrians and cyclists, and better and easier ways to take public transit.

What's available on the curb will impact which modes can proliferate in the network, giving cities the opportunity to clarify the roadway environment that surrounds the curb and make all modes more predictable.

“To make corridor-level changes possible, leading cities are adopting and acting on policies that prioritize reliable transit and safe bicycling infrastructure first, followed by other important uses of the curb like deliveries, passenger pick-ups, green stormwater infrastructure, and small public spaces – as well as managed parking,” CityLab reports.

Here are some of those policies in action on urban streets.

Curb Space –> Flex Zone

Seattle’s curbside management policies caught attention in 2016 when they swapped the term “curb space” for “flex zone” to acknowledge the need for every curb to adapt to its corridor’s needs differently.

“On Seattle streets, buses, cars, streetcars, bikes and trucks move people and goods. Sidewalks provide space for pedestrians to move and wait for their bus and get to where they want to go,” writes the Seattle Department of Transportation. “In between the two is the flexible space where people find their bus, park a car, hail a cab, drop off a passenger or make a delivery.” Flex zones are prioritized by the needs of each street. The move resulted in a major payoff, as CityLab has reported: a boost in bus ridership at a time when, nationally, fewer people are taking mass transit.

Parking-Protected Bike LanesParking Protected Bike Lane in San Francisco

The volatility of car and truck drivers pulling in and out of curbside spaces can be dangerous for cyclists, who have to react quickly and can be forced to swerve into oncoming traffic. So San Francisco is separating the two. Instead of the bike lane being placed between parked cars and the traffic lane, San Francisco’s “parking-protected bike lanes” (pictured right) run curbside between the sidewalk and parked cars. The first of these bike lanes was completed in March 2017.

Kittelson is working with SFMTA to develop concept designs for some of the city’s busiest corridors, such as 5th Street, which is currently a two-way, four-lane undivided street with on-street parking and curbside loading/unloading. The 5th Street Improvement Project will incorporate parking-protected bike lanes and bus loading islands to improve safety for people taking public transit.

Performance-Based Pricing

Washington, D.C. is managing curbside parking demand with a data blend that enables them to forego sensors in every parking spot. parkDC: Penn Quarter/Chinatown was a pilot of an “asset-lite” demand-based parking program. Using data from spatial and temporal sampling, including partial sensor coverage, payment data, fixed and portable cameras, computer vision algorithms and other data inputs, parkDC is able to update pricing in real time using fewer resources than other demand-based pricing programs. At the end of the pilot, the number of block faces at target occupancy (70-90% in use) increased by 31%. Among other important outcomes, better management of curbside parking mitigates congestion and dangerous driving maneuvers associated with circling downtown blocks for parking spaces.

Toward More Efficient and Productive Curbs on Urban Streets

Ultimately, cities need to go curb by curb, street by street to determine priorities and policies. A data-driven approach to reconfiguring curbside space will reduce conflicts between modes and identify the most productive uses of space in each corridor. Read the second installment in this article series to learn about collecting and interpreting data to make safe and smart curbside decisions.