Living street

The U.S. Department of Transportation's Manual on Uniform Traffic Control Devices focuses primarily on vehicular traffic and how to optimize its movement.[1] Conversely, the concept of a living street focuses on creating healthier, more walkable, and more livable places while optimizing environmental benefits.[1] Living streets aim to prioritize the safety of all street users, especially more vulnerable groups such as pedestrians and cyclists, by improving infrastructure to accommodate all street users.

Daily Traffic Congestion in LA

Urban Design Professor Donald Appleyard's Street Livability Study in the 1970s suggested streets in the United States were often noisy, polluted, and dangerous, and residents and cities both do not feel in control of creating clean and safe street environments.[2] Livable streets aim to create cleaner and safer environments[3] by "greening" streets and creating spaces where cars are guests to pedestrians and cyclists. This concept prioritizes the environment and the community over accessibility and movement of traffic. The Dutch woonerf is an example of this concept: it eliminates exclusive spaces for pedestrians and vehicular traffic, instead encouraging the whole street to be accessible to pedestrians and providing trafic calming measures for vehicles.[4] In their paper Reclaiming the Residential Street as a Play Place, Trantle and Doyle argue that woonerfs increase traffic safety and children are more likely to play near or in the street.[5]

The living street reimagines the role of the street by reconsidering its purpose and who it is intended to serve. When implemented, the street may be a cooler, safer, more walkable, more attractive place that promotes the user’s health and wellbeing.[6] It can serve as a recreational space for the neighborhood and improve the air quality through reduced carbon emissions and other air pollutants as well as improve water quantity and quality. Living streets can also prevent erosion and flooding through storm water management and reuse.[7] It has three major components: being green, cool, and complete.[8]

Green streets can help alleviate water security issues.[8] Green street design involves implementing stormwater management strategies to protect nearby water sources from pollutants, and encouraging water reuse. Managing water at the source reduces the amount of pollutants carried into local water supplies. Pollutants can be harmful to local ecosystems and water quality.[9] Such strategies include building planter boxes, which can absorb stormwater runoff with pollutants, and bioswales which can filter stormwater and recharge groundwater supplies.[10] Trees are another aspect of the green street design: they can reduce the effects of the urban heat island (see "Cool streets" below) since they shade paved surfaces from heat. They also use evaporative cooling and can sequester carbon, improving air quality and reducing carbon emissions.[11]

Cool streets aim to reduce the effects of the urban heat island (UHI). Traditional streets are made of dark impervious materials which absorb energy from the sun and create warmer surrounding temperatures which increase both emissions and stormwater temperatures.[12] Replacing these surfaces with lighter-colored materials lets the street surface reflect solar energy.[13] Consequently, the lower temperatures reduce both emissions, meaning communities may have fewer temperature-related illnesses, and the temperature of stormwater runoff, reducing its impact on aquatic life in receiving waters.[14] These lighter surfaces are also more resistant to heat degradation and their reflective properties allow for more visibility at night.[8]

Complete streets are intended to be accessible, accommodating, and safe for pedestrians and cyclists by implementing strategies to promote active travel. They are intended to provide social equity for all users. Factors such as trip duration, path gradation, and typical weather conditions are assessed to see if active travel is possible.[8] Design strategies in complete streets include raised crosswalks - a traffic calming device that brings motor traffic to the level pedestrians walk at - and curb extensions which increase space for street amenities such as plants, benches, and trees.[15]

Since the late 19th century American planners have faced problems concerning traffic congestion and street safety. The two typical designs of American neighborhoods were the gridiron plan and curvilinear street, but safety concerns regarding motor vehicles brought new street patterns in the 1920s, one being the “neighborhood unit.” The Radburn plan developed by Henry Wright and Clarence Stein in the late 1920s as well as Clarence Perry’s proposal in 1933 used the "neighborhood unit" to try to encourage prevention of traffic on residential streets.[16]

In the 1930s and 1940s, increased highway traffic provoked the publication of the Community Builders Handbook. Written by the Federal Housing Administration, the handbook provided a hierarchy of street types such as arterial, collector and minor access.[16] However, unsafe conditions were still being observed, and street types were not meeting their intent.[17] Following this, cul de sacs and diverters were used in places such as Montclair and Grand Rapids to encourage streets to fulfill their assigned street type.[16] In the 1950s and 1960s, extensive urban development projects concerning housing and highway construction brought increased volumes of traffic and improvements focused on the flow of the motorized vehicle.[16] Colin Buchanan’s Traffic in Towns published in 1963 in England introduced his American companions to the concept of “environmental areas”, places where pedestrians are safe from motorized vehicles.[16] He acknowledged that there was an environmental capacity to every street, and pedestrian safety, air and noise pollution, and lighting were all of particular concern. This report influenced design in countries such as Sweden and Australia as well as San Francisco's Urban Design Plan.[2]

At the national level, the Federal Highway Administration sponsored a study conducted by Donald Appleyard in the 1970s looking at the impacts of traffic on residential streets.[18] From the study (which looked at 500 homes in the San Francisco area in comparison to other international street designs) they found that residents were deterred by the unsafe travel speeds of motorized vehicles.[18] This was a particular concern in areas with child and elderly populations. Noise and pollution decreased the overall livability of the streets, while more social interaction and perceived privacy was found on streets with lower traffic volumes. Stress, occupancy turnover, and adapting to unsafe living conditions were also results of unfavorable traffic conditions.[18] The findings of Appleyard’s Street Livability Study inspired the San Francisco City Planning Board to launch the San Francisco Urban Design Plan in 1971 which introduced the idea of the “protected residential area.”[19] The goal of the design was to slow down traffic to acceptable speeds in residential areas through infrastructure improvements for active transport as well as traffic calming measures. While the city’s focus in street design used to be increasing the flow of motor traffic, this new approach discouraged high travel speeds. Following this plan, San Francisco developed the Protected Residential Area Program (PRA) which allowed neighborhoods to petition for traffic management measures. This encouraged community participation as well as equity and safety for all residents.[16]

Dutch, Danish, and German cities have incorporated several design concepts and policies surrounding traffic management. They have seen improvements in overall street safety and for the more vulnerable modes of transport such as walking and cycling. The focus on active transport in countries like the Netherlands may be attributed to the more car restrictive policies they have had in place since the 1970s.[20] The woonerf, home zone and Spielstraße require motorists to drive at walking speeds and yield to pedestrians, cyclists, and playing children who have the same rights in road use.[21]

These cities have implemented traffic calming measures, have dedicated auto-free zones for pedestrians and cyclists, enforce lower travel speeds, and have limited and more expensive parking compared to the United States. They have no turn on red, a concept the United States has had since the 1970s which has led to a drastic increase in pedestrian and cyclist injuries.[22] Street design in the United States tends to focus more on travel speed of motorized vehicles. In these European countries, the mindset is that motorists should anticipate the actions of pedestrians and cyclists. Their traffic calming measures have had a significant impact on traffic accidents: Dutch neighborhoods have seen traffic accidents reduced by up to 70% in some areas,[23] whereas a study looking at Denmark, the United Kingdom and the Netherlands found that traffic-related injuries in traffic calming neighborhoods fell by about 53%.[24]

These studies and ideas have changed some of the mindsets and ideas of street planning and design in the United States. Some planners and designs in the United States now see the street as a place to live, gather, and play instead of a means to get from one place to another. They have started to address how to make streets clean and safe for everyone, and a place where the community can gather and socialize.[16]

Some cities in the US such as Portland and Minneapolis have increased cycling rates over five-fold from 1990 to 2008 through the implementation of the same practices used in Europe, such as improved cycling infrastructure, public education on traffic safety, integration with public transportation, increased bike sharing, and traffic calming measures.[25] These cities have found that even though the United States has a history and culture associated with using motorized vehicles as a means of commuting, policies and infrastructure can influence people’s actions and habits.[26]

Stormwater management along a sidewalk

Street trees shade surfaces and provide protection from the sun. This can lead to a longer life of the infrastructure, which saves in replacement costs and turnover for the surfaces. They can also reduce surrounding temperatures and improve air quality.[28] Stormwater management is another strategy, that includes permeable paving and bioretention planters and swales. Permeable pavement can be used for sidewalks, bike lanes, parking lanes, and low-volume streets to allow water to infiltrate through surfaces and reduce runoff to nearby water.[29] Bioretention planters and swales are typically used in planting strips or curb bulb outs to treat storm water runoff. Swales can be used where the water can infiltrate the soil, whereas planters should be used when infiltration into the existing soil is not desired.[30][31]

Zebra crossing

In order to reclaim streets as a play area for children and a place for the community to gather and socialize, traffic calming measures can be put in place. This may include introducing speed bumps, changing the surface of the road, or creating artificial chicanes. These measures physically enforce reasonable speeds, rather than signage which can have little effect on the driver’s actions - instead, drivers are forced to be more aware of their actions and the actions of other street users.[32] Other traffic calming measures include raised intersections and pedestrian crossings which bring the vehicles to the pedestrian level, indicating cars do not have full ownership of the road and must be vigilant of other road users. Chicanes, narrower travel lanes, and roundabouts purposefully slow down cars to safer speeds. Extensive car-free areas, wide, well-lit sidewalks, refuge islands for crossings, crossing signals, and zebra crossings provide safe and convenient facilities for more vulnerable road users. The woonerf in the Netherlands incorporates some of these traffic calming techniques but goes further in that it uses the concept of the shared street where separate spaces are not defined and pedestrians have access to the entire street. Developing the street more by filling in the “street wall” is another design measure to encourage walking and cycling. This concept consists of filling in the empty spaces and large parking lots often found adjacent to streets to make the street not only more attractive or inviting but also more accessible to these active commuters.[33] In addition, moving parking lots to the back of the store like found in European countries gives priority to pedestrians and cyclists near the entrance.[21]

Living streets focus on how to best move people and not just the car. The design aims resolve issues such as high-speed traffic arterials, too few intersections, and lack of sidewalks.[33] There may be dedicated transit lanes, sidewalks and bike lanes, and spaces that serve the entire community regardless of age, income, or ability. Measures such as bike lanes and safe, accessible maintained sidewalks will provide the infrastructure for the community to become active commuters.[8] Further design strategies such as medians can serve as a safety net for pedestrians and indicate pedestrian presence for motor vehicles, while reducing lane and land width and bulb-outs can decrease a pedestrian's crossing distance. Speed bumps and traffic circles can make the street seem like less of a highway.[8] Instead, these measures encourage lower travel speeds and therefore bring increased safety for other street users. Adequate signage, signals, and lighting can also be used to make all users aware the street is a shared space.[8] These measures may require even less space to carry more people.[33]

Mixed-use development in Lonsdale St., Braddon, Australia

Compact and mixed-use development is another strategy of the living street since how land is used will determine trip distances and preferred modes of transportation. Cycling is typically done at distances below 3 km and walking is typically done at distances below 1 km.[21] If trip destinations are within walking or cycling distance, people may utilize the sidewalks and bike lanes for their commute. In addition, compact neighborhoods will also make transit a realistic option because the population will exist to provide the necessary ridership.[33] Advocates suggest establishing strong neighborhood centers with local accessibility - instead of creating separate commercial and residential areas, which promote car use through increased trip lengths – that will lead to more sustainable and livable conditions.[34]

The design of living streets makes it easier for people to satisfy the need for daily physical activity since they can walk or cycle as a part of their commute. Walking and cycling provides a form of physical activity and accounts for numerous health benefits that can combat current concerns for public health. In comparing obesity rates with walking and cycling for commuters between countries, studies show that the countries with a greater number of cyclist and pedestrian commuters tend to have lower rates of obesity.[36] Lack of exercise can also lead to other chronic health problems like diabetes or heart disease. In addition, walking and cycling can reduce the number of cars on the street, bringing a reduction in air, water and noise pollution as well as carbon emissions. This cleaner air may also reduce asthma and other respiratory diseases in urban areas.[37] The CLAN study conducted by Carver and Crawford in 2008 revealed that the built environment and street design can also play a role in the health and wellbeing of children.[38]

Government injury rate statistics from Californian cities and European countries show that higher numbers of cycling and walking may increase safety. Public health consultants such as Peter Jacobsen suggest this is because there is a greater awareness of cyclist and pedestrain movements so motor vehicles are more prepared to react and avoid accidents.[39] In addition, motorists may also be cyclists or pedestrians themselves which makes them more sensitive to the needs and rights of these more vulnerable groups.[21] Larger groups of these active commuters may also justify more rights to the road and an increase in improving and enhancing public infrastructure geared toward them. Fewer cars can also reduce traffic congestion.

Living streets give more options for how people travel or get from one place to another and balances options so it is safe for all users. In addition, revitalizing existing areas instead of continuing suburban sprawl helps utilize and build upon past investments in infrastructure. This revitalization may include improved infrastructure that encourages people to sit, walk, and gather instead of being driven away by noisy traffic polluting the air. In addition, more people out and about in the streets can help reduce crime.[33]

The concept of living streets also works to prevent alienation children may have with their surroundings by providing them spaces to play and develop in an outdoor environment. The spaces allow children to experience different environments and communities as well as the ability to develop new relationships with others in these safer spaces.[40] As a result, children living near these streets will be healthier individuals since they have a greater and safer exposure to the environment around them and are able to develop relationships and interact with various individuals.[41]

Living street designs are intended to serve all users. The concept hopes to advance livability for the entire community by envisioning the street as providing multiple benefits for several types of users instead of simply a means for motorized traffic to get from one place to another. This investment in public infrastructure also seeks to provide more economical alternatives for the user since they do not need a car to get from place to place.

Instead of focusing solely on the movement of cars, living streets are designed to move people and focus more broadly on several different modes of transportation that can be accessible to all people.[42] A significant deterrent to active transport is a lack of traffic safety, especially to groups of society like the elderly and children who are more vulnerable to these dangers and, with current streets, often need more protection from car traffic.[43] Increased walking and cycling in these groups would improve their physical activity and expand their mobility and independence.

In addition, current streets may have uninviting landscapes or be unsafe to walk or bike on, meaning driving a car is often the only safe or practical option. There is no place to gather or congregate or for children to play, and it is hard for the more vulnerable groups like children and those with disabilities to travel in anything but the car.[44] Since lower income or senior citizens may not be able to afford or operate cars and rely on other modes of transportation to move around and be independent, living streets provide more economical and independent modes of transport. In addition, implementation of street trees, foundations, and plazas can allow people to gather and enjoy the street in a shared and communal experience.