The science of stop and go traffic starts long before projects are completed
By Val Beerbower
The year was 2006. The Pirates of the Caribbean sequel was the blockbuster hit of the summer. A new social media startup called Twitter made its debut. And road construction projects just completed this year in the Miami Valley had barely begun their planning phase.
Street-building projects average about 12 years from concept to completion, according to Brian Martin, executive director of the Miami Valley Regional Planning Commission (MVRPC).
But how does a traffic project help us get from point A to point B the fastest? And what’s the science between what makes us all stop and go on the road?
It all starts with collecting data. All long-range planning for new streets, widening projects and other major infrastructure alterations begin with collecting information such as: Where is new development occurring? Does this require new roads? What is the current land use and how might that change?
Data provide a snapshot of how streets are currently used and that information is overlaid with statewide and national trends to determine a long-range plan. This infrastructure has to serve populations and businesses that might not exist yet.
Where regional groups like the planning commission coordinate large-scale projects like building new roads or widening streets, individual municipalities are responsible for ongoing maintenance and traffic management within each community.
John Zelinski, a senior engineer for the city of Dayton’s Department of Public Works, says one of his objectives is improving traffic volume along thoroughfares and through intersections. “We observe traffic volumes at different times of day, at different locations,” Zelinski says. “Traffic light timing is optimized for quickly moving people through.”
He says most signals also communicate with a central server, which allows engineers to monitor their status. Meanwhile, filling potholes, resurfacing roadways and other maintenance issues keep public works employees on their toes.
Civil engineers like Zelinski also work with different departments to assure roadways are adjusted to the most appropriate application for nearby activities. “We have to understand land use in order to plan for traffic,” he says.
Residential areas, commercial districts and industrial zones have different users that rely on the surrounding infrastructure. Layering in routine maintenance, plus water, sewer and power lines means dozens of factors contribute to any roadway project.
As a recent example, routine street maintenance had to dovetail with the schedule for a multijurisdictional gas pipeline project. “There are potholes to fill and curbs to repair, but it doesn’t make sense to do that only to have another team come in after you and rip everything out,” Zelinski says.
But vehicular traffic is only one use for city streets. Jon White works in the city of Dayton Department of Planning and Community Development and his job revolves around the people who live, work and play along these streets.
“Engineers design the roads and planners design the community,” White says. Together with civil engineers, planners design the roadways from sidewalk to sidewalk—the full space within the public right-of-way. “I’m thinking about quality of life issues rather than just zipping cars through an intersection.”
Again, land use plays an important factor, including historical context. “In a dense urban environment, like in downtown Dayton, we had streetscapes and infrastructure that were built before automobiles,” White explains.
“Then as you introduce more vehicles you see modern transportation policies focusing on cars. The question we face today is how do we ameliorate the auto-centric design and create an environment best suited for everyone, including bicyclists, pedestrians and mobility-challenged?”
Historically, new infrastructure often ignored quality of life, particularly for those in disadvantaged social status. Angela Schmitt is a Cleveland-based correspondent for Streetsblog, a nonprofit advocacy group for transportation issues nationwide. She says when most highways were built communities suffered.
“When the federal highway system was built in the 1950s and ’60s it did a lot of damage. It damaged the competitive position of cities,” she says. “Many black, ethnic and low-income neighborhoods had their homes leveled… More than 1 million people were forced from their homes by urban renewal policies in 993 U.S. neighborhoods.”
Federal urban renewal policy included “slum clearance.” Most people living in these areas lacked the means to combat highway planning the way wealthier, typically white neighborhoods did. Once built, the highways opened vast suburban areas for development.
“That allowed a lot of white people to flee cities and establish relatively homogenous communities in the suburbs,” Schmitt says. Meanwhile, the marginalized communities, now displaced from their homes, found themselves with limited mobility—limited further by the highway itself.
But progressive communities are changing how transportation affects residents and taking steps to create equity. White says reviewing how streets are used today can generate streetscape plans that are more consistent with how people currently use the space and optimize travel for the greatest number of people. “Road diets” reduce the number of vehicular traffic lanes to increase space for bike lanes and wider sidewalks for pedestrian travel.
Contrary to what one might assume, removing lanes of traffic doesn’t lead to further congestion. “Reducing speed doesn’t impact drive times if you’re going from 35 to 25,” Schmitt says. “Stopped traffic is what’s going to have the biggest impact.”
Likewise, supporting pedestrian and cycling infrastructure doesn’t necessarily mean congestion gets worse. “If people feel safe using alternate modes of transportation, even with reduced lanes and slower speeds, we can still feed volumes of vehicular traffic in and out because there are fewer cars,” White says.
Investments in public transit also help reduce congestion and have an environmental benefit. One MVRPC project acquired funds to upgrade some RTA buses to hybrid vehicles. “We’re a mid-sized city but we think bigger,” Martin says. “I think we do some pretty cool stuff.”