With the “efforts” of various companies and trends, autonomous driving is indeed getting closer to us. But this may not only be a relationship between people and cars; road transportation itself will also undergo necessary and important changes with the arrival of autonomous driving.
Recently, the National Association of City Transportation Officials (hereinafter referred to as “NACTO”) issued a report on the blueprint for future autonomous vehicle cities. This report provides a comprehensive and detailed introduction to how future automated transportation will integrate into the entire urban built environment, and how these changes will be accepted and popularized.
Why will roads occupy less area in the future? Why will roads look more like gardens in the city? What changes will our personal lives undergo? All of these are mentioned in the report. Leiphone (WeChat public account: Leiphone) has conducted key compilation and analysis based on the original report. The following is the exciting content.
Introduction to NACTO
The National Association of City Transportation Officials (hereinafter referred to as “NACTO”) is a non-profit organization and also an alliance of city transportation departments. It aims to provide safe, sustainable, convenient, and reasonable transportation options to support the needs of a strong economy and convenient life. It represents the opinions of large cities on local, regional, and national transportation issues. At the same time, it is also committed to establishing a common vision, sharing data, and conducting regular exchanges with member cities in seminars and conferences to improve the state of street design and transportation practice.
Currently, NACTO has more than 20 “member cities” in the United States, including Atlanta, Austin, Boston, Chicago, Houston, New York, San Diego, and others. Internationally, it also includes Toronto, Vancouver, and others.
1. Vision: Roads are no longer restricted zones but living spaces for humans
At the beginning of the report, Janette Sadik-Khan, chief commissioner of the NACTO Executive Committee and commissioner of the New York City Department of Transportation, first put forward her vision for autonomous transportation in cities—people-oriented, which is also the foundation of the entire blueprint for autonomous vehicle cities.
Through new transportation technology, streets will be redesigned to first meet human needs: sidewalks will become shared commercial spaces rather than just for parking; driving lanes will only occupy the road space they need, but at the same time can efficiently carry passengers. Finally, urban space will focus on the ‘mobility’ that truly makes cities move, such as public transportation, walking, cycling, and shared rides.
Most importantly, the blueprint actually regards the upcoming autonomous driving as a good opportunity to transform streets for humans, not just a technological revolution.
2. Policy concepts and actions
1. Six principles for building an automated city
Undoubtedly, every city needs strong policies to guide the future of autonomous driving. Based on the six principles mentioned above, the following are the key steps that NACTO member cities are taking and implementing to build the future of automated cities.
Safety
1) Set sidewalk and speed limits (20 mph) for bicycles and vehicles.
2) Use third-party platforms to anonymize and aggregate data of vehicles operating in the city to identify dangerous areas and redesign streets for safe operation.
3) Establish operational and geometric principles for city streets to determine the safe operation of driven and autonomous vehicles.
Mobility
1) Create a citywide AV working group, and all municipal departments must participate in autonomous vehicle planning.
2) Stimulate active modes: Build streets to prioritize sustainable and active modes such as transit, walking, and cycling.
3) Regional collaboration and promoting internal operability: Comprehensively cover all areas of the city, integrate them on one platform, and facilitate customer use.
Balancing right-of-way
1) Stop road expansion: Update existing transportation modes and reduce road demand by improving automation efficiency.
2) Ride transit lanes: Design travel routes specifically for high-volume transit services to increase passenger throughput on key corridors.
3) Repurpose underutilized roads to ensure the safety and comfort of pedestrians walking along sidewalks.
Real-time street management
1) Data-driven street management: Use third-party data platforms to safely and seamlessly exchange street data and support real-time street management.
2) Curb pricing: Create delivery and pick-up/drop-off management plans to maximize user experience and reduce potential hazards for pedestrians.
3) Optimize curb access: Maintain a dynamic, digital, and visual sidewalk inventory to democratize sidewalks.
Carrying more passengers with fewer vehicles
1) Prepare for a future without parking: Reduce parking restrictions in zoning; develop prototypes with adaptable parking lots and infrastructure for future conversion.
2) Enhance electrification: Support shared electric vehicle use by allocating space for charging stations and adopting congestion pricing based on occupancy.
3) Strategic investment: Modernize partnerships by laying out extensive routes.
Public interest guiding individual actions
1) Clarify obstacles to public-private cooperation: Use “ride-sharing clauses” to create replicable eligibility requirements so that public and private sectors can eliminate obstacles that once hindered work in American cities.
2) Engage the public: Increase transparency in technology development and pilot projects.
3) Cities are part of automated operations. Discussions about future technology operations are indispensable.
2. Practices during the transition period and future prospects for city streets
Although the pace of technological change is fast, the changes in urban infrastructure during the process of embracing autonomous vehicles are gradual. For example, city streets and sidewalks become important places for testing new policies, technologies, materials, and street types. In fact, in 2017, many American cities were investing local funds into public transportation infrastructure and services through major voting initiatives.
In the future, urban automation will go through a process from partial automation to full automation. In the early stage, cities will make strategic investments to prepare for connected automated technology and will greatly promote cycling and walking. Speed limits will be reduced to 20 mph, and dynamic pricing will be set for sidewalks. This pricing method will also be first implemented in American cities. Under the combined effect of the above factors, the demand for walking, cycling, and core transportation will surge, and cities will enter an era of shared vehicles. More and more cities will implement VMT (Vehicle Miles Traveled) pricing to reduce urban congestion. In the final stage, when city vehicles achieve full autonomy, VMT will further decrease, achieving true people-orientedness.
3. The future of autonomous vehicles and city streets
In detail, the following twelve key points should be noted for building future city streets:
Two-way operation: In a connected vehicle environment, streets can operate in both directions. However, two-way operation should not come at the expense of pedestrian flow, and intermediate or transit platforms should be established.
Only one direction per lane: Outside of highways, streets should be limited to a single lane in a single direction, excluding dedicated transit lanes; residential streets can be designed as “yield to pedestrians” streets; major streets should provide high-capacity bus or rail services.
Lane width: Lanes should be kept to a minimum width. In most cities, lanes of 10 feet or less can meet lane guidance needs. In the long run, lanes should not be divided by markings but should be relatively flush with sidewalks and center lines.
Integrated design for freight and transit vehicles: In the future, limited street space and coordination with surrounding infrastructure can be used to accommodate passenger and freight business needs.
Managing sidewalk demand: Future cities can more conveniently manage the sidewalk environment dynamically. Sidewalks may provide various functions throughout the day, such as public space, bike-sharing stations, information kiosks, etc.
Flexible mobility hubs: Passengers can get on and off at designated hub points.
Managing vehicle gaps: As more passengers are integrated into multi-purpose vehicles, pedestrians will have frequent crossing opportunities and safety will be greatly improved.
Street technology: Sensors and other real-time mobility management technologies will be embedded in vehicles as much as possible, bringing greater convenience.
Mode-specific street management: Shared spaces can define the future of street operation. Motor vehicles will be restricted to low speeds on many streets, reducing pressure on freight corridors.
Time management: At different times, streets can be actively managed according to different needs. For example, pedestrian activity may trigger closures when reaching certain thresholds, and streets may temporarily operate at 10 mph.
Lower and more stable speeds: In city centers, speeds will be limited to below 20 mph.
Pedestrians should be detected, not connected: People do not need to carry sensors or signals to ensure safety. Vehicles should be able to detect pedestrians in all situations and ensure they do not harm pedestrians on the street.
City streets in the automated era should prioritize pedestrians, cyclists, and transit riders. Smaller and fewer lanes can reduce conflicts between vehicles and pedestrians and leave space for bike lanes on all streets. Buses should run with priority on dedicated lanes, becoming the backbone of the urban transportation system. Sidewalks can be more flexible, supporting more public and private uses. After speed limits are set at 20 mph, the overall lanes for private cars will be greatly reduced. As a result, the capacity of dedicated transit lanes and public vehicles will be greatly improved. Future city streets will bring value to every user through sound design and wise policies.
With the implementation of these policies, we can imagine the “picture” of future city streets, such as:
Seamless street management: Future cities can manage streets seamlessly to reduce the negative impact of private cars on urban life. The space occupied by vehicle infrastructure will be greatly reduced, bringing streets back into people's lives (as shown below).
Minimizing crossing distances: The size of driving lanes and intersections will be greatly reduced to minimize crossing distances and improve pedestrian experience (as shown below).
Fully separated bike lanes and wide sidewalks can enhance the feeling of street space. Low speeds allow pedestrians to safely switch to any lane (as shown below).
Every inch of future streets will prioritize pedestrians. Under the implementation of rules, vehicles at short-distance intersections will create safe and pleasant street environments for pedestrians (as shown below).
Frequent vehicle gaps give pedestrians opportunities to cross the street without spending too much time. Complex signal lights can also delay vehicles and pedestrians to some extent (as shown below).
In the future, each different type of street will play a different role to achieve more efficient and more humanized urban street management. For example, multi-way boulevards will have only one through lane in each direction; central city highways will prioritize providing unobstructed passage space for vehicles; major transit streets will concentrate pedestrian activities; residential streets can become the heart of the city through flush sidewalks and green infrastructure; secondary intersections can become hubs for bicycles, cars, and other mobility services.
4. Safety design and considerations
The transformation of transportation technology provides an opportunity to rethink how streets operate and how cities manage traffic flow. To this end, NACTO proposes a series of considerations and assumptions about road design in this report.
1. More frequent and safer street crossings
In current city streets, traffic movements are mainly concentrated near intersections or crossings. Pedestrians can only cross at intersections, causing significant delays when reaching their destinations. Sidewalks are very narrow, and cyclists often have to share a lane with vehicles.
In the automated era, vehicles will be optimized for low-speed driving. Fewer lanes and shorter crossing distances will make “direct street crossing” (technically known as mid-block crossing) a normal behavior again. Frequent and formal mid-block crossing points (every 50-100 feet), combined with sufficient gaps in vehicle lanes, will reduce the burden on intersections.
2. Stopping distance
To provide a safe street environment for street users, speeds can be actively programmed and managed in city centers (e.g., speed limits below 20 mph). For example, the current stopping distance is 60 feet with a speed limit of 35 mph; in the future, it may be possible to have a stopping distance of 11 feet with a speed limit of 15 mph.
3. Vehicle gaps
In the future, cities can avoid impassable highway-like arterials and instead have multi-lane roads with simultaneous traffic. As more passengers are integrated into multi-purpose vehicles and there is sufficient space between vehicles and multi-lane roads, pedestrians will have a safer and more efficient crossing experience.
4. Intersections to roundabouts
In an environment with autonomous vehicles, intersections can accommodate more fluid traffic flow. Some small intersections may also become slow-moving roundabouts rather than continuous stops and starts.
5. Pick-up and drop-off
Currently, to drop off passengers, vehicles on major streets should first turn right, which inevitably causes some traffic congestion. In the future, parking spaces on major streets can be closed, which not only reduces congestion in main lanes but also frees up more space along sidewalks for other uses.
6. Shorter crossing distances
Narrower lanes allow for shorter crossing distances. When paired with short medians, the distance for crosswalks and vehicle delays can be minimized. For example, the current crossing distance is 40 feet; in the future, it can be reduced to two 8-foot short medians.
5. New mobility system—maximizing vehicle carrying efficiency
In the future, cities can leverage technology to maximize the carrying capacity of travel lanes, allowing more people to move in limited space. However, if single-occupancy vehicles dominate, cities will find it difficult to achieve maximum capacity. Bicycles and high-capacity transit must be key components of streets, with dedicated areas to meet the mobility needs of large numbers of residents.
Taking the above figure as an example, the upper part shows the current hourly capacity of city streets, while the lower part shows the future hourly capacity after applying the new mobility system. It should be noted that both are based on the assumption of a lane width of 10 feet and a capacity standard of 1,000 people per hour. First, the most obvious comparison is the addition of dedicated bus or rail lanes in future cities, with a capacity of 10,000-25,000 people per hour. As for bike lanes, the capacity of protected bike lanes may be four times the current level—4,000 people per hour. However, there is no difference in the capacity of sidewalks, mixed lanes, and private car lanes between the two; both have 9,000 people per hour on sidewalks, mixed lanes have a capacity of 1,000-2,800 people, and private car lanes (the upper part is private cars, the lower part is autonomous vehicles) have a capacity of 600-1,600 people per hour.
Conclusion
NACTO shows us the blueprint for future city streets and automation through a report of over 60 pages. One particularly interesting point is that, based on the people-oriented premise, through a series of management of city streets, people in future cities may return to the era of ‘arbitrarily’ crossing the street. Whether it is AI, the Internet of Vehicles, automation, or autonomous driving, these technologies will ultimately maximize the release of human nature, allowing everyone to live comfortably.
