Vision Zero is the elimination of all traffic deaths and injuries. Vision Zero is attainable, but achieving it in San Antonio is not easy, nor could it happen without significant change. Eliminating traffic fatalities and injuries means changing our transportation habits and land use.
The Comprehensive Plan now under development is not only the opportunity to accommodate growth through 2040, but the chance to plan for growth while achieving Vision Zero.
In two studies, researchers from Texas A&M University and the University of Utah found that traffic crashes, fatalities, and injuries are more attributable to design of the built environment than random error of road users. In an extensive review of pedestrian safety research literature, Reid Ewing and Eric Dumbaugh noted environmental designs that promote higher speeds, more driving, and more four-way intersections systematically cause more pedestrian and cycling fatalities and injuries. The study reported the American Association of State Highway and Transportation Officials (AASHTO) Green Book, the standard for highway and street design, recommends improving safety by using the highest design speed possible. The result of greater design speeds is greater operating speeds. Greater design speed causes more traffic fatalities and injuries in urban environments, however.
Dumbaugh and Wenhao Li examined traffic crashes in San Antonio from 2003 to 2007. They found land use, design speed, and intersection design influenced traffic crashes. Streets with greater design speeds had more crashes, streets with slower design speeds had fewer crashes. Strip malls and big box stores were associated with more crashes, while pedestrian-scaled retail decreased crashes. Three-way intersections reduced crashes, while four-way intersections increased crashes. This study confirmed earlier research that greater speed causes more crashes.
The World Health Organization (WHO) design manual on pedestrian safety restates findings from multiple research studies. Pedestrian and cyclist safety has been neglected throughout the world, but more importantly, improving pedestrian and cyclist safety improves safety for all road users.
The relationships between design speed, operation speed, crashes, fatalities, and injuries is well understood. That explains why we reduce speed in school zones, on residential streets, and other situations where we expect there could more likely be a traffic crash, and especially a crash with a pedestrian. Yet research finds roads designed for high speeds remain the most dangerous to pedestrians and cyclists in urban environments, because pedestrians do not restrict themselves to schools, residential areas, and parks.
Vision Zero is attainable by reducing speed. Research shows speeds are reduced when the built environment communicates the need for slow speed, which in urban areas means narrower lanes, fewer lanes, and smaller clear zones next to streets. Slow speeds can also improve pedestrian safety by encouraging more courteous driving. Dumbaugh and Li reported that motorists driving at walking speed yielded to pedestrians 100% of the time.
The WHO reported that greater numbers of pedestrians improve pedestrian safety. Dumbaugh and Li link slow speeds to better walkability, and better walkability to better livability. Judging by the frequent request for better walkability in community plans, it seems that San Antonians agree.
However, making slow speeds practical, improving walkability city-wide, and mitigating the inherent hazards of highways and arterial streets in the urban environment means a very different built environment than today’s San Antonio. Achieving Vision Zero in San Antonio requires significant transportation and land use policy changes, and doing so would benefit not only community safety, but also sustainability.
Decisions made during the comprehensive planning process can set the foundation for a built environment and transportation system that lives life at human speed and provides the environment to achieve Vision Zero. Alternatively, the comprehensive planning process can perpetuate life at automobile speed, expand arterial streets and highways, and expand a built environment that ensures Vision Zero will not be achieved in San Antonio.
Built environments where Vision Zero can be achieved offer high quality of life, are walkable and encourage cycling, and are more sustainable than auto-dependent, sprawl communities. Achieving Vision Zero in San Antonio requires more than changing driving habits or transportation policy. It requires comprehensive planning to build an environment that is walkable and sustainable.
The alternative to Vision Zero is accepting traffic fatalities. We do not and should not have to accept traffic fatalities. Vision Zero should be a fundamental principle during comprehensive planning. It cuts across the entire comprehensive planning process, and it should be integrated into the process from the very beginning.
A comprehensive plan built with traffic safety and Vision Zero as the driving standard will be very different from a plan built with mobility or level of service as the transportation standard. A comprehensive plan that moves the city toward zero traffic deaths and injuries will also move the city toward more walkability, better multi-modal transportation, more mixed-use development, less driving, improved air quality, and slowing growth at the boundary.
*Featured/top image: Narrow streets and wide sidewalks in Brooklyn, N.Y., encourage more pedestrian activity and slower drivers. Photo by Kevin Barton.