WORLD RESOURCES INSTITUTE – Cities Safer by Design
Summary:
- Connected and compact urban design.
Cities can be safer when they have more compact and connected urban form that reduces the need for driving and fosters shorter trips. In a study from the United States, urban sprawl—places with less density, long blocks, and a lack of street connectivity—has been “directly related to traffic fatalities and pedestrian fatalities” (Ewing, Schieber, and Zegeer 2003).
- Safer vehicle speeds. Enhancing safety depends on lowering vehicle speeds and reducing conflicts. Lower automobile speeds, especially those below 30 kilometers per hour (km/hr), have been found to drastically lessen the risk of fatalities (Rosen and Sander 2009). The fatality risk for pedestrians with vehicles traveling at 50 km/hr is more than twice as high as the risk at 40 km/hr and more than five times higher than the risk at 30 km/hr (figure 1.2). For example, bringing traffic speeds down to safer levels can be achieved through a set of evidence-based traffic calming measures (Bunn et al. 2003).
- Walking, bicycling, and mass transport emphasized. Cities with lower levels of vehicle travel have connected networks of high quality walking, bicycling, and mass transport infrastructure. Cities can make bicycling practical and safe, reducing injury rates as bicycling increases (Duduta, Adriazola, and Hidalgo 2012). U.S. and European cities with higher rates of bicycling have fewer overall traffic crashes. These cities also have good cycling infrastructure, high street connectivity and compact urban form (Marshall and Garrick 2011).
Safer City Attributes:
▪▪Block size
Longer block faces allow higher vehicle speeds, placing pedestrians at higher risk. Longer street blocks are unsafe for pedestrians. Long blocks commonly have crosswalks only at intersections, indirectly encouraging unsafe midblock crossings. Long blocks also encourage higher vehicle speeds due to fewer junctions that interrupt travel. More junctions mean more places where cars must stop and pedestrians can cross.
▪▪Street connectivity
Connectivity refers to the directness of links and the density of connections in a street network. A highly connected network has many short links, numerous intersections, and minimal dead ends. As connectivity increases,
travel distances decrease and route options increase, allowing more direct travel between destinations and creating more accessibility (Victoria transport Policy Institute 2012). It affects the need to travel and the attractiveness of walking and cycling.
▪▪Street widths
Street width often means the roadbed width, which is the distance between curb edges on opposite sides of a street, or, where no curbs exist, from pavement edge to pavement edge. The width of space allowed for vehicle
travel on streets greatly influences pedestrian crossing distance and the roadway width potentially available for other uses, such as bike lanes, parking lanes, or landscape curb extensions. This is separate from the width of the space between buildings or the total public right of way, including sidewalks and other areas not dedicated to vehicles.
▪▪Access to destinations
Pedestrian destinations or points of interest are normally places that people find useful or interesting or where employment, retail, and leisure uses concentrate. High-quality networks should be provided particularly between key destinations such as residential areas, schools, shopping areas, bus stops, stations, and places of work.
▪▪Population density
Population density refers to day and nighttime population per square kilometer or other unit area. Density is not directly related to safety, but can play a role in complementing other design factors. Locating more people within walking distance of services, public facilities, and transport can help reduce the need for driving.
Things a City Can Do to Improve Travel Safety
- Tap into the expertise of all road users. To build a successful safe and friendly city, consultations with all the road users are imperative. Different users are the experts on their own needs.
- Engage multiple sectors. Government cannot do it alone. Encourage public and private partners from multiple sectors to take part in the effort to be more inclusive of all road users, both as a business opportunity and a moral imperative. Museums, theaters, grocery stores, banks, pharmacies, churches, and block associations can all be leaders in creating safe and friendly cities.
- Recognize that a safe travel environment is a contributor to the economy.
- Ensure that pedestrians, bicyclists, transit and bus passengers know about existing opportunities and resources.
- Adopt a “safe-in-everything” approach to community planning and the design process. Redesign street intersections with the safety of all road users in mind. Focus on areas near shops and services and on areas with high rates of pedestrian injuries. Add public seating on streets in accordance with location recommendations from pedestrians.
- Advocate for improvements in public transportation. Focus on making transportation safe, accessible, and welcoming to all users. Good lighting, clear signage, and courteous drivers can be just as important as having an appropriate infrastructure in place.
- Increase accessibility to opportunities that promote health and socialization. Expand efforts to make parks, walking trails, swimming pools, beaches, recreation centers, and public events accessible and welcoming to all groups. Offer fitness and recreational programming designed for and of interest to all users.
- Last but not least, plan for safety through mobility plans, city plans, traffic safety action plans, and other plans to prioritize safety in city designs.
Quick Facts
- Road crashes are the leading cause of death among young people ages 15–29, and the second leading cause of death worldwide among young people ages 5–14 (WHO 2003).
- People from lower socioeconomic backgrounds are more likely to be involved in traffic crashes, and often live in areas with low-quality infrastructure (WHO 2003).
Older pedestrians and cyclists can account for up to 45 percent of pedestrian fatalities and up to 70 percent of cyclist fatalities (Oxley et al. 2004).
- The needs of bicyclists should be considered throughout the road network. A well- connected bicycle network should consist of interconnected bike lanes, cycle tracks, and traffic-calmed streets with priority for bicycles, and special considerations at junctions and intersections, which are designed to prioritize cyclists’ needs.
- Shared bicycle streets—also known as bicycle boulevards—are low vehicle
-volume and low speed streets that have been optimized for bicycle travel through treatments such as traffic calming, vehicle reduction and redirection, signage and pavement markings, and intersection crossing treatments.
- A safer intersection for bicyclists may include elements such as colored pavement, markings, bike boxes, bicycle signals, and simultaneous green phases for cyclists. Special attention to bicycle facilities at intersections and driveways should be given to maintain visibility of the bicyclists to motorists and to reduce the risk of turning conflicts with motor vehicles.
- For public transport to have a positive impact on safety, it requires a well-organized system and priority. Our research shows that when cities give this priority, they have a better safety impact than conventional or informal transit. Data from the implementation of Bus Rapid Transit (BRT) systems—such as Macrobus in Guadalajara, Transmilenio in Bogotá, and the Janmarg in Ahmedabad—show a significant reduction in crashes and fatalities on their respective corridors. Research at EMBARQ has focused on identifying risk factors and common crash types on such transit ways to provide safer design guidelines. The main safety risks on transit corridors depend on its geometric design rather than the type of technology used (bus or rail) or the region of the world it is in.
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