Transportation

Warning: Sharp Curves Ahead

By Andrew Plowman, Director of Transportation Design, WSB

Exploring the why behind the twists and turns of road design.

Throughout the COVID-19 era, many Americans have opted out of air travel and are instead packing up their cars and hitting the road for an old-fashioned road trip. A survey conducted by Farmers Insurance found that more than 60% of people are planning to travel by car or RV over the next few months.  But as we weave and wind our way through the mountains or travel over the hilly plains, our minds can wander into the why behind the infrastructure that’s bringing us to our destination. We ask, why do roads curve?

There may seem like there is no rhyme or reason to the sharp curves or slight turns along interstates or highways, but there are many reasons roadways curve.

Right of Way

If you’re a rancher, you certainly wouldn’t want a highway slicing down the center of your land. In many cases, Right of Way causes a road to curve around a piece of property rather than through.

Subgrade Conditions

The subgrade is the existing soil located below the pavement and aggregate layer of the roadway.  At times, the existing subgrade is made up of organic material or clays that will continue to settle. As the roadway settles it can crack causing damage over time. Rather than dig very deep to remove this material, a roadway alignment may curve out of the way to miss the bad soil conditions.

Profile Considerations

Profile considerations become increasingly important in states where roads need to climb to different elevations.  To maintain a grade that isn’t too steep, a road will curve from Point A to Point B to gain distance which flattens the slope. 

There are many reasons a road may curve that extend beyond this list. The technical aspects of roadway design are vast. As you make your way to your next destination, see if you can spot the reason a road may curve.

Bret Weiss, WSB president & CEO, appointed to Governor’s Council on Connected and Automated Vehicles

Bret Weiss, WSB president & CEO, was appointed to the Governor’s Council on Connected and Automated Vehicles. Formed in 2019, the Council studies, prepares and assesses the opportunities and challenges associated with the widespread adoption of connected and automated vehicles and other intelligent and emerging transportation technologies.

Weiss joins 13 appointed members, twenty ex-officio members and co-chairs Margaret Anderson Kelliher, Minnesota Department of Transportation (MnDOT) commissioner and VSI Labs President, Phil Magney. Each appointed member must have relevant experience in the automotive industry, technology, cybersecurity and data privacy, business and finance, transit, higher education, workforce training, insurance, mobility, freight, labor, public safety, bicycle and pedestrian advocacy, elder care, or tort liability.

“I am thrilled to join such an esteemed group of innovators and trailblazers that will help advance Minnesota’s connected and autonomous vehicle efforts,” said Weiss. “The future of intelligent transportation systems is much closer than we think. As a state, we’re at the forefront of developing strategic solutions that will only help strengthen Minnesota’s infrastructure.”

Weiss’ experience with infrastructure-related engineering and transit systems will assist the Council as they work together to review connected and automated vehicle development and trends, explore partnership opportunities, propose policies to safely test and deploy connected and automated vehicles and consult with communities experiencing transportation barriers.

As a firm, WSB has partnered with MnDOT on several initiatives related to connected and automated vehicles including the current CAV Strategic Communications, Engagement, and Relationship Building Framework Plan, the Minnesota CAV Strategic Plan and the 2017/2018 testing of connected and automated vehicles in winter conditions.

Gov. Tim Walz and Lt. Gov. Peggy Flanagan announced the appointments in a press release earlier this month. The full announcement is available at https://mn.gov/governor/news/?id=1055-442968.

WSB hires Christie Saenz to growing right-of-way team

Saenz will lead the firm’s right-of-way efforts in Texas

Austin, Texas – Engineering and consulting firm WSB announced today that Christie Saenz is joining the organization as a senior right-of-way specialist. Saenz joins the firm’s Austin office where she will lead WSB’s right-of-way efforts throughout Texas.

“I am thrilled to welcome Christie to WSB,” said Jay Kennedy, WSB’s vice president of Texas operations. “In the last year, we’ve been working to expand our expertise in the Texas market and the addition of Christie will continue to drive momentum.”

Saenz joins WSB with over 25 years of experience in the right-of-way industry. Throughout her career, she’s managed the acquisition of over 1,000 parcels for the Texas Department of Transportation and central counties and cities. Most notably, Saenz worked on the SH 99 Grand Parkway, Segments F-2, G-1 & G-2 for Texas Department of Transportation in Harris and Montgomery Counties, SH 36 for Texas Department of Transportation in Brazoria and Fort Bend Counties, the Bell Boulevard Realignment for the city of Cedar Park and Dacy Lane Phase II for Hays County in Kyle, Texas.

“I am really looking forward to joining WSB’s fast-growing Texas team and expanding the firm’s right-of-way services,” said Saenz. “Investment in infrastructure and development is strong throughout the state and I see many opportunities to support our client’s right-of-way needs.”

As part of WSB’s right-of-way team, Saenz will support clients with their right-of-way projects by providing project management, acquisition and relocation services. As a consulting engineering firm, WSB provides transportation planning and design, water/wastewater utility work and community planning services throughout the state of Texas.

WSB Selected to Design TH 169, Rebuilding Gateway to Greater Minnesota

WSB is thrilled to partner with the Minnesota Department of Transportation (MnDOT) to provide final roadway and bridge design services for the Highway 169 (TH 169) Reconstruction Project.

TH 169 is a significant north-south highway in Minnesota. It serves rapidly developing communities and is a gateway to exploring recreational areas in Greater Minnesota. The highway is heavily traveled by both vehicles and pedestrians. Expanding the highway is intended to improve safety and reduce the average rate of collisions in the area.

Jody Martinson, vice president of transportation at WSB, anticipates this project will have a lasting impact and looks forward to delivering a safer commute for surrounding communities.

“This project is incredibly important to users of the TH 169 corridor,” said Martinson. “Being able to work side-by-side with MnDOT to improve the safety and mobility for motorists and pedestrians is extremely gratifying. WSB is excited to utilize technology and innovative solutions to improve the efficiency of design and construction.”

The reconstruction will address operational, infrastructure and mobility issues, all important elements considered when the project was selected for the Corridors of Commerce (CoC) program. The project will replace four signalized intersections with interchanges and consolidate access points, drastically improving safety and mobility. Local roadways will be reconstructed to create ADA accessible routes at the interchanges. The TH 169 project is expected to reduce roadway delay by more than 1,000 hours per day, eliminate $1.7 million in annual crash costs, and provide more reliable travel times for the public.

The project is also a CMGC project. As a CMGC (Construction Manager/General Contractor), the process will involve several stakeholders and team members throughout the design and construction process. The project will also require strong coordination and communication with MnDOT. Project manager, Peter Muehlbach formed an expert team to ensure the CMGC process is efficient, effective and economical for reconstruction.

“When fully utilized, the CMGC design process allows for a more collaborative work environment between designer and contractor,” said Muehlbach. “I am excited for the opportunity to make design decisions together with our MnDOT, Sherburne County, city of Elk River and Ames Construction partners.”

Additionally, the project team will leverage state-of-the-art and emerging technologies to provide sustainable solutions during the design phase. By utilizing modeling tools, WSB will streamline construction management, drainage and utility relocation processes.

Planning for the TH 169 Reconstruction Project is underway with final design set to begin this summer. Phased construction will begin in fall 2022 with project completion set for 2024.

Fallon Avenue Overpass receives APWA Honorable Mention

The Fallon Avenue Overpass project recently received an honorable mention for this year’s 2019 Minnesota Chapter APWA Project of the Year Awards. The APWA Awards program recognizes excellence in public works. We were honored to partner with the city of Monticello on a project that connects the community.

Southwest LRT Groundbreaking

One of Minnesota’s largest infrastructure projects officially moves into construction.

WSB acted as West Segment Water Resources Lead for Metro Transit. 

Federal, state, and local officials gathered in Hopkins to break ground on the Southwest LRT project in late November. The $2.003 billion project will be the largest infrastructure project in the state’s history and is expected to create 7,500 construction jobs, with an estimated $350 million payroll.

Our Water Resources and Environmental Compliance teams assisted Metro Transit as the West Segment Water Resources Lead. We completed the erosion and sediment control design, storm sewer design, permitting, bridge and wall drainage work. Our team was also responsible for identifying and designing Best Management Practices (BMPs) to meet permitting requirements and designed the storm sewer infrastructure that will connect existing municipal and Minnesota Department of Transportation (MnDOT) systems to one another. Additionally, we prepared water resources-related documents, including preparing plans and specifications, quantifying wetland and floodplain impacts, completed hydraulic analysis for risk assessments and performed water quality analysis of the proposed BMPs.

The Roundabout Craze

Roundabouts have been used throughout Europe and Australia for decades but have only gained popularity in the United States in the past 20 years. There are currently more than 3,500 roundabouts in the United States. Minnesota has also joined the roundabout craze, with more than 140 roundabouts built as of 2014, and upward of 20 additional roundabouts built each year.

Some jurisdictions, such as the New York State Department of Transportation and the City of Bend, Oregon, have implemented a “roundabouts first” policy. These policies require that a roundabout be analyzed and, if feasible, should be the preferred option.

To understand why roundabouts have become so popular, it is important to understand what a roundabout is and why roundabouts perform so well compared to other intersection alternatives.

What is a roundabout?
A roundabout is a type of intersection that includes a circular central island and lane(s) traveling around the central island in a counterclockwise direction. A roundabout is different from traffic circles and rotaries.

There are four main differences between rotaries/traffic circles and modern roundabouts:

Right of way

• In a roundabout, vehicles already within the circle have the right of way.
• In a rotary or traffic circle, entering vehicles have the right of way.

Size

• Roundabouts are comparatively smaller (typically 80-180 feet in diameter).
• Rotaries and traffic circles can be as big as 300-400 feet in diameter.

Changing lanes

• Changing lanes within a roundabout is not allowed. Lane integrity must be maintained through to exit.
• Changing lanes is allowed in rotaries and traffic circles (though sometimes this is difficult, as shown in the famous scene from National Lampoon’s European Vacation).

Deflection upon entry

• Deflection is crucial to appropriate roundabout design, as it promotes lower speeds and encourages yielding.
• In a rotary or traffic circle, entering traffic aims to the right of the central island, which does not promote lower speeds or yielding.

How to drive a roundabout
Roundabouts can have a variety of configurations, depending on the capacity requirements on each approach. Driving a single-lane roundabout is easier than driving a multi-lane roundabout, but the basic concept is the same. The primary concept to understand for a single-lane roundabout is this: yield to pedestrians at crosswalks and to vehicles to your left within the circulating lane.

Multi-lane roundabouts add one more step to the direction listed above: choose the appropriate lane. For example, choose the left lane if you are going left or through, and choose the right lane if you are going right or through. (Yellow line: left or through; Blue line: right or through)

Benefits of roundabouts
Compared to standard intersections, roundabouts offer significant benefits.

• Safety: This is one of the primary reasons roundabouts have become so popular. Research shows that roundabouts reduce fatal and injury accidents by as much as 76%, due to slower speeds and the existence of fewer conflict points.
• Capacity and reduced delay: Due to the continuous flow of traffic, roundabouts can handle larger volumes than signalized intersections in the same amount of time. It is a common misconception that intersections are more efficient.
• Better fuel efficiency and air quality: There is less idling by vehicles in a roundabout than in an intersection where vehicles must wait through red lights. This equates to a reduction in fuel consumption and vehicle emissions.
• Landscaping opportunities: The central island of a roundabout is a great place to provide landscaping and can serve as a gateway to a community or district.
• Safety for pedestrians: This is another common misconception about roundabouts. It is often thought that because a pedestrian crossing at a roundabout is uncontrolled, that it is not as safe as a signalized crossing. The figures below illustrate why the roundabout crossing is safer than crossings in standard intersections.

Roundabouts are being implemented in communities throughout Minnesota and continue to score well on many federal grant programs. We continue to stress the importance of educating drivers about how to properly navigate a roundabout, through ongoing communication with the public across multiple platforms.