Complete Streets Design in High Volume Corridors

August 18, 2021
Rick Tipton, PE, PLS &

High-volume local corridors are usually thought of as busy, congested streets. That’s correct for not only vehicular traffic but bicyclists, bus passengers, and pedestrians as well. Busy streets mean citizens are mobile and active, necessitating increased transit options for everyone. Thus, municipalities across the U.S. are asking transportation professionals to move more people in more efficient ways.

Nearing the quarter-century mark of the new millennium, our need for safe, efficient, and sustainable transportation alternatives and roadway connectivity continues to grow. Active transportation mandates from communities looking to increase bicycling and walking access along our streets coupled with municipalities’ requirements for safer intersections create complexities for 21st century transportation planners.

Advanced technologies to develop those plans and operate sophisticated multimodal networks create opportunities to progress many of the items on transportation advocate’s wish lists, with the goal oftentimes to connect motorists, pedestrians, bicyclists, transit users, and vehicles into a connected transportation system. But challenges to achieving complete streets in high-volume corridors await those tasked with integrating these diverse modes of transport.

Learn from the Past

Our country was founded on the ability to travel vast distances as quickly and efficiently as possible. The building of roads often took precedence over concerns for other modes of transit due to the profitability of trucking and the need for commercial growth. Planning for all travelers took a back seat until economic, social, and environmental factors merged into the complete streets movement early this century.

In the mid-2000s, divergent advocacy groups from bicyclists, seniors, minorities, and even realtors started coalescing around the idea of smart street planning. Although federal complete streets legislation failed to pass into new laws, its central tenets filtered to local, regional, and state agencies that saw a groundswell of support for more complete street projects. The National Complete Streets Coalition reports that 448 regional and local jurisdictions, 27 states, Puerto Rico, and Washington, D.C. have adopted complete streets policies, with many more adopting non-binding resolutions supporting smarter transportation planning.

Takeaway: Complete streets is a movement that is increasing in popularity and so transportation planning will need to accommodate a more mobile citizenry

Lanes for Everyone

Approaching a new or upgraded street design often starts with creating space for all desired transportation modes. Creating street zones in roadways for pedestrians, bicycles, and vehicles (including public transit) can be a challenge in narrow corridors. Deciding when and where these priority street elements should exist, their minimum and preferred widths, and other design elements that can or should be included require coordination and diligent planning.

Part of the planning starts with assigning street designations for each roadway in the plan. For example, mixed-use streets have access to vehicles, people, parkland, commerce, and public transportation. This is contrasted with residential and green-style parkways that offer more opportunities for pedestrians, bicyclists, and landscaping. Other considerations for each street designation include lane widths, right-of-way allocations, and typical traffic volume.

Another challenge in achieving balance is where to place the pedestrian zone (sometimes called the public realm) in relation to other street elements including the roadway, parking, greenspace, and frontage, i.e., shops and homes along the street. Another frequent request of smart street planners is to incorporate more greenery into our communities, both for aesthetics and cleaner air. The increased shade opportunities are also recognized as a benefit to provide relief to citizens in extreme heat conditions.

Takeaway: We need to balance the needs of disparate multimodal stakeholders using more technology-driven and innovative design and planning systems.

Keep Traffic Moving

Achieving optimal traffic flow of vehicles, bicycles, and pedestrians should be a part of any connected city design. Taking a holistic approach to how all the elements move within a traffic grid by considering how turns, signals, walkways, and signals interact is vital for the safety and free flow of all types of traffic.

One aspect of achieving an optimal traffic flow pattern is target speed – the pace you want a person to drive. Target speeds should balance the needs of all anticipated street users. Matching design to driver expectations, the target speed should match the posted limit. Traffic studies are helpful to determine the volume and safe speeds.

There are smart street design elements that help speed up or slow down traffic depending on what is needed. For example, coordinated traffic light patterns will efficiently move traffic through crowded downtown streets. Slowing down traffic can be accomplished using chicanes, pinch points, corner islands, turn wedges, and roundabouts. There are also opportunities to add more green space and parkland to communities while calming traffic in these plans.

Safety Concerns

Safety is of utmost concern for complete street designers and engineers. Citizens need to feel they can move about knowing they and their families are safe. But what do transportation professionals look for in safety improvements while building complete streets in high-volume corridors?

Along with studying and implementing road designs that provide optimum speed limits and other speed-related elements like roundabouts, designing streets for pedestrians and bicyclists, including sidewalks, raised medians, curb extensions, and bus pullouts all improve safety. Pedestrians benefit from crossing an intersection in a single cycle, rather than two cycles for example. And providing safe bicyclist accommodation needs to consider how to accommodate cyclists who don’t feel safe or comfortable on streets shared with motor vehicles.

Finally, one of the most critical policy effects from the Americans with Disabilities Act (ADA) is the proliferation of design elements for seniors and the disabled. High-volume corridors need more comprehensive public transportation access points, bulb-outs, pedestrian refuges, and smaller curb radius to reduce vehicle access and improve pedestrian-friendly areas.

Takeaway: Slow and steady wins the race to move everyone (and everything) efficiently. Think creatively to find safe solutions for multimodal traffic in high volume areas.

Room to Grow

While much of the focus of complete streets is on cities or busy commercial areas, growing suburban and exurban zones is where smart planning can significantly impact the future. Planning for population growth in the beginning phase of road design, including bike paths, walkways, and green space is frequently requested by municipalities. Adding additional road lanes is also top-of-mind when creating a holistic plan for complete streets to anticipate higher volume in growing areas. Even existing, high-volume corridors can benefit from full street design to widen walking and cycling lanes where additional space is available.

These new transportation corridors can also see improved connections to urban areas. The need for bus, rail, and commuter parking lots connects residents to urban cores while keeping cars and trucks off the roads to improve air quality and overall traffic conditions. Planning for these commuter services like light rail or bus rapid transit is increasing in popularity but can be challenging due to the involvement of multiple governmental agencies and municipalities.

Anticipating innovative technologies to improve interlinked transportation networks is being added to many connected streets designs. Intelligent transportation systems (ITS) are a growing planning method as Mobility as a Service (MaaS), and smart vehicle technologies merge with traditional transit operations. ITS challenges complete street designers to envision advanced multimodal transportation systems using automation and electric mobility options to improve the efficiency and sustainability of transportation networks.

Takeaway: Coordination with municipalities and their stakeholders is key to accommodating transportation growth and connectivity. Look for ways to incorporate multimodal systems into plans while anticipating how to best leverage technology.

Invite the Public

One of the core philosophies of complete streets is that all citizens should have safe, comfortable, and convenient access to transportation – whether walking, driving, bicycling, or using public transportation. Thus, soliciting community input on transit planning and investment has grown along with the complete street movement.

Gaining public support is especially important with traditionally underserved groups like people living with disabilities, minorities, and older adults. Historic division of urban neighborhoods can be partially addressed with elements of complete street designs such as improved public transportation opportunities and greenway access.

Meeting with community groups and local business owners via open forums and online surveys can determine collective goals for broader access to all residents. Gaining input from all citizens benefits both the project and improves community relations. Local communities learn the complete streets’ benefits and trade-offs, and those stakeholders can advocate for other smart street investments within and beyond their neighborhood.

Takeaway: Municipalities are looking for transportation planners to gain their constituents trust and buy-in during the planning phase of complete streets projects.