Designing the Intersection of the Future
What is an intersection?
The intersection is a study of human physical interaction, of space, motion, speed and time. Contemporary society is characterized heavily by intersections, as seen in the work of Piet Mondrian. Mondrian was one of the earliest artists inspired by the pattern of organizing the modern world in a system of grids and perpendicular intersections. His paintings during the 1930's and `40s document the age of the metropolis and the conscious structuring of society for the interaction of information and people. As reflections of the rectangular grid system at the basis of computers or city streets, Mondrian's visions are metaphors for any system of communications or travel in contemporary society.
However, the idea of the intersection has always existed. Long before cars and traffic lights, travelers had to direct themselves as they clustered together to form the first villages and cities. Even in the natural world, the concept of intersections plays a crucial role in the harmony of life. Our own bodies serve as incredible systems of intersections, networking sensory and response information, nutrient distribution, excretion collection and expulsion, and the ultimate information processing unit--the brain. Human life is completely dependent on the efficient and effective operation of these "intersections".
Why today's intersections need to be redesigned
Intersections are aptly called that because they are locations where many different modes of transportation cross. But while a tremendous amount of engineering and design has been advanced for motor vehicles, when it comes to pedestrians there's far less research. Disabled people have their own set of design needs and these differ and may even conflict depending on the disability. Therefore, our project will be to design the urban intersection that takes into account all the different modes of transport that pass through it. A special emphasis will be placed on persons with physical difficulties such as paraplegics and the blind, as well as persons with mental disabilities, such as retardation. The intent is to maximize safety, efficiency, and aesthetics, while staying within a reasonable budget. (taken from Gateway handout)
Our focus: Rt. 9A at the intersection of Liberty and West Streets, Battery Park, NYC
Special Considerations for NYC intersections
While Paris is a combination of a radial city plan as well as a grid system that allows for radial expansion, NYC is almost exclusively a grid system because of the special constraints that being an island creates. Most importantly, Manhattan is restricted from expanding radially by geographic barriers, specifically the Hudson and East Rivers. As a result, land in NYC is particularly valuable and must be conserved. Our intersection design needs to take this factor into account.
Another special concern will be NYC's many different travel modes and the incredible density of human population. With so many different types of travel, there is a wide range of speeds, motions, and special physical requirements, such as wheelchairs. Therefore, special attention must be directed towards a strict regulation of travel, while giving the population a feeling of space and freedom.
Three factors we will consider in our design:
1. How people move through intersections:
It's a procedure we take for granted--step off the curb, step into the intersection, then step on to the curb on the other side. But moving through intersections really can't be dismissed that easily. We videotaped the Astor Place intersection for fifteen minutes, and in even that short amount of time, identified eleven different types of movement:
3. Groups of Pedestrians
6. Skate Boarders
8. Visually Impaired
9. Disabled (wheelchairs)
10. Baby Strollers
We also was noticed that several of these groups had distinguishing movement requirements, which often conflicted with the needs of other groups. Here are some of our most important observations:
A. Bikers frequently ignore traffic rules. It's amazing how many bikers flagrantly ignored basic traffic conventions. For example, three bikers on the video were riding against the flow of traffic. And another sped around a curve so fast that he nearly collided with oncoming traffic. Bikers on the tape also had a tendency to weave in and out of traffic, which is understandable, since bikes are more maneuverable and the riders are naturally tempted to take advantage of that benefit. But clearly, these practices can be hazardous to pedestrians.
B. Wheelchair pedestrians depend on sidewalk ramps. The most dramatic moment on our video is when a woman in a wheelchair crosses the street from Starbucks to K-mart, but instead of getting on the curb at K-mart, makes a left turn into oncoming traffic. We later realized that she was forced to literally endanger her life because there was no ramp on the K-mart curb.
C. Skaters take up greater width than pedestrians (because they jut out left and right, unlike pedestrians who walk in a straight line for the most part).
D. Pedestrians tend to use crosswalks, but not always.
E. Groups walk slower. By groups, we mean groups of people who know eachother. This is probably because of conversations.
F. Strangers spread out. There are cultural implications in how people walk through intersections. People who don't know eachother tend not to walk next to eachother. Therefore, the space in an intersection is taken advantage of to the fullest.
When you think about it, an intersection has quite a job to do: Eleven different types of movement, simultaneously, at different speeds, requiring different amounts of space. The question for our class this semester will be: How do you make sure all eleven types of people make it to the other side of the street without colliding or infringing on eachother's needs?
2. Land Use:
In New York City, space is the number one commodity. Therefore, land use becomes a very important intersection design specification. We have researched several intersections in NYC and Brooklyn and have discovered some trends in good and bad land use.
In Manhattan, we noticed first that many intersections use triangular islands to divide traffic. These triangles are created from several different scenarios. One is the joining of two streets moving in the same direction. For a safe intersection, there must be a gradual merge between the two. Therefore, a triangular island is created in the middle. If these intersections form a large enough triangle, it can be built upon. A good, and very famous example of this is where Broadway and Fifth Avenue cross at 23rd street. Here the Flatiron Building takes up the triangle. At another site, the Lafayette/Cooper Square merge into 4th Avenue, several little islands are created due to cross streets. They are too small to build on, but create an open atmosphere for pedestrians.
In Brooklyn, we noticed that streets are still organized in a grid, but several streets run on an angle to the grid. Therefore, many small triangular cross sections are created. We noticed that along Flatbush Avenue from Atlantic Avenue to Grand Army Plaza every cross street forms one if the triangles. They are a huge waste of space in terms of building and expanding, but they do liven up the neighborhood by providing benches and a place for pedestrians to relax. In addition to triangular intersections, at Grand Army Plaza we also observed a very large, European style, circular intersection. It encircles the Grand Army Plaza Memorial Arch and connects many streets and Avenues as well as Prospect Park, the Brooklyn Botanical Gardens, and the Brooklyn Museum. This intersection functions very well, but uses a tremendous amount of space. For a pedestrian to travel across, he/she needs to be in very good physical condition.
3. Street Furniture:
Street furniture usually implies permanent objects, such as traffic lights, parking/standing signs, street lights, street signs, phones, bus stops, newspaper/magazine boxes, and hydrants. But it can also include temporary items like construction barriers/signs, newspaper stands, and hot-dog vendors. In designing and placing street furniture, we realize that four main factors need to be taken into account:
How does the object serve the street or intersection? Is it needed? What effect will it have in the area it is being placed?
The streetlights in Greenwich Village are designed differently than those on Madison Avenue around 86th Street. This is because each area wants to create a particular image. A street furniture designer should ask: What does the area want people to think about it? Does the object suit the essence of what the area is about?
How much space does the object take up? Does it get in the way of movement?
Is the street to small for this object?
E. Quality, Maintenance and Repair:
What will the furniture be made of? How long can it last? Will it have to be repaired frequently? Who will maintain it? How does it need to be maintained?
4.Street signs and signals
Since two bodies cannot be at the same place at the same time, whenever two bodies try to come to the same point at the same time with a high velocity, something disastrous is guaranteed to happen. To avoid this, some order must be maintained. This is the basic function of the signs and signals we see on the street. There are four major categories of signs: Regulation Signs, Be Aware Signs, Information Signs, and Pavement Markings.
Regulation signs: The Regulation Signs are the signs that regulate the traffic across an intersection. Traffic lights, Walk signs, Stop signs, and Yield signs are examples of Regulation signs. They usually have a red background and white letters printed on them. The message they carry are often in a tone of command, such as "STOP", "DON'T WALK", and "DO NOT ENTER". The red background makes them easy to notice. The combination of the color and tone of the message make people aware of the seriousness of the sign.
The Warning Signs warn drivers of unexpected road conditions. They usually have a yellow background and black picture or text print on them. The message they carry is generally brief and combines a picture for a clearer interpretation. Because of their bright background, these signs are easy to notice. However, because they show up based on the road conditions ahead, people are not looking for them ahead of time. Therefore, they are more likely to be missed by the driver than Regulation Signs, especially if there are distractions like trees or other signs. This is why they are not used to convey messages about actions that result in punishable acts.
Information Signs:The Information Signs provide vital information about the place around the signs. They come in various backgrounds and shapes. Green background and white lettering are one kind. Parking signs with white background and red letters are another. Usually, Information Signs are smaller than other signs, since they aren't as vital.
Pavement Markings: The Pavement markings are symbols painted on the street to divide the space or state its purpose. They are generally in white or yellow paint, and some contain special reflective materials for clearer night time viewing. Only simplistic symbols can be used, since it is difficult to read words on the street at 40mph.