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How a 5-Step Preliminary Design Process Improved a Street Project

This 5-step preliminary design process used by one project team helped answer the question, “Rehab or reconstruct?” with a solution that worked for all stakeholders.

When the time comes to stop patching our streets and start looking for a longer-term solution, we’re faced with an age-old infrastructure question: rehab or reconstruct? 

In this article, we’ll examine a preliminary design process that helped officials in Washington County and the City of Marine on St. Croix, Minnesota, discover a solution that aligned not only with their goals, but community members, too.

“The Marine on St. Croix community is very strong and connected. The project team knew we couldn’t design a solution that left out a critical piece of the picture: We needed participation in the design process, and acceptance, from community members who would be living with the solution every day,” says Sue Mason, PE, SEH project manager.

1. Beginning with the end in mind

After years of patching and routine maintenance, the pavement along a corridor traveling through residential areas of Marine on St. Croix, Minnesota, and into the rolling countryside of Washington County, needed to be updated.

Knowing a design process that integrated comprehensive public engagement would help resolve key issues and gain community acceptance, a team of city and county staff and their consultant set out to understand the long and short-term goals and objectives for the corridor.

Given the project’s sensitivities, the project team solidified a short list of key goals that will resonate with anyone undertaking street projects today. The goals included:    

  • Achieve community acceptance through stakeholder engagement process
  • Improve safety and pavement condition in the corridor
  • Identify and implement storm drainage improvements that balance all needs
  • Improve multimodal facilities
  • Capitalize on available funding
  • Protect (avoid, minimize, mitigate) natural resources and wetlands
  • Consider (protect, maintain, enhance) area's rural and historic character

With the length of the corridor and its varying character, however, the project team knew a one-size-fits-all solution would fall short of these goals. In this case, the best solution would be, in fact, many solutions. 

The segment of the corridor in Marine on St. Croix, Minnesota, that was due for updates.

2. Considering constraints and opportunities using context zones

To meet each of the key goals consistently, and to help communicate design constraints and opportunities to the public, the team divided the corridor into three segments or “context zones.” Each segment in the corridor was defined by its varying character and unique constraints. 

Zone One

Near MnDNR park land, Zone One is defined by its rolling hills and wooded areas. Importantly, the section has many vertical and horizontal curves that don’t conform to Minnesota State Aid for Local Transportation requirements.

Zone Two 

Zone Two, with nearby wetlands, and running through a residential neighborhood, has sidewalk with some curb and gutter. A portion of this segment has poor underlying soils and needs improved drainage.

Zone Three

Zone Three, in a residential neighborhood area with a church and also near a trout stream, has some existing curb and gutter and a sidewalk gap. It also has challenging terrain with steep slopes and curves.

3. Designing alternatives for each zone

Once the project area was segmented into zones, the team began designing options for each. For this project, the team designed four alternatives for each of the zones, with the exception of zone one (more on that below).


Rehabilitate Existing – Surface water flows directly into nearby property or wetlands. Does not improve water quality or flooding issues.


Reconstruct, Ditch Drainage – Improves water quality and flooding issues, but has widest construction footprint.


Reconstruct, Curb & Gutter Drainage – Improves water quality and flooding issues, and has narrowest construction footprint.


Reconstruct, Hybrid Drainage – Allows flexibility for context-sensitive design. Improves water quality and flooding issues.

Why four solutions? Drainage. 

“Water ages pavement as much as traffic. So, good drainage design is important for a long-lasting road pavement,” says Mason. “We designed alternatives, for the most part, based on the different ways to capture and provide water quality treatment before discharging into the nearby environmentally sensitive wetlands or trout stream.”

To that end, preliminary designs for each segment included one rehabilitation option along with three reconstruction options each handling drainage differently: ditch drainage, curb and gutter drainage, a hybrid drainage solution combining ditch on one side of the road and curb and gutter on the other. 

Zone one, as mentioned, was an outlier on this project. No alternatives were designed other than simple replacement of the pavement due to right of way limitations, environmental factors and budget constraints. Also, a pavement rehabilitation was the only option that kept the rolling hills and curves valued by the community.

Unable to make any fundamental changes to the roadway, the team was still able to make some improvements. They addressed safety by designing slightly narrower lanes, adding a slightly wider shoulder, improving ditch and culvert drainage, and including an intersection connection.

One of the zone three challenges was the curve and hill near 5th Street with historic retaining walls nearby. Design standards required flexibility so they didn’t impact property and drastically change the existing character of the area. The County pursued and won a design variance for the horizontal curve, which then avoided impact to the existing wall. The new, proposed retaining wall in front of the church will be natural kasota stone, also in keeping with the historic character of the neighborhood.

4. Evaluating and refining the options

The designs were refined over a period of time through a feedback loop created by formal and informal stakeholder engagement. Whether public meetings or conversations with individual property owners, the project team continued collecting input that was used to improve and enhance the design options. 

Design options finalized, the project team needed an organized method for comparing the trade-offs of each. The team kept scoring simple, by giving each design a pass or fail rating based on whether or not it met the project goals. The design team and community members could glance at the alternatives, and quickly understand which alternatives best aligned with project goals. Scores tallied, the hybrid system (offering a mix of ditch and curb-and-gutter drainage solutions) came in first, with curb and gutter coming in a close second. 

Pass or fail? Each design option within each zone was weighed against initial criteria developed by the project team with community input. Hybrid drainage first, with curb and gutter a close second.

5. Selecting the best alternative with community help

Finally, and in order to ensure that the community had another opportunity to provide feedback, the project team invited the public to weigh in on the alternatives at an open house. Attendees were able to voice their opinions and provide comment. 

What did they prefer? 

Much to the surprise of the project team, the solution preferred by the community also brought the most change: curb and gutter.

“If we would have suggested curb and gutter at the outset, the community might have pushed back,” adds Mason. “The preliminary design process, which included so many touchpoints with the community, who was very engaged and respectful, helped everyone come to a solution together.”

That sentiment was echoed by Kristin Petersen, SEH engagement specialist on the project. 

“Resistance to change is a powerful force in any collective decision,” says Petersen. “We knew from the outset that a high level of communication, with both the greater community and individual property owners, was needed. In the end, the focus on engagement throughout the process built trust and allowed the community to embrace change.”

A rendering of the curb and gutter solution that scored well with the community as well as City and County officials.

4 Tips for Better Preliminary Design 

1. Start at the end. You won’t get anywhere without first determining the purpose and need for your project and then developing a clear vision for success. Kick off the project with a meeting (or series of meetings) that involves an inclusive goal-setting process where necessary stakeholders weigh in. Understand what each stakeholder needs then work toward it.

2. Give yourself options, but not too many. The preliminary design process is, in part, about selecting the best option from the shelf through a series of refinements. Too many options, however, will slow down the decision-making process and make communication with the public difficult. Follow your gut and intuition. You’ll know you have too many when they become difficult to explain from one another.

3. Save a seat at the table for the community. When the community is left out in the beginning, they can show up at the middle or end of your project with significant opposition, resulting in expensive delays. Invite them to weigh in at important stages of the project and, through your dialogue, you’ll gain the acceptance you need to move forward.

4. Be flexible, but firm. By letting stakeholders weigh in, preliminary design implies a flexibility toward other possible solutions. It’s okay to help everyone understand what design details are non-negotiable and that the City Council and County Board, with recommendation from staff, make the final decisions. Hopefully, you have developed enough respect and trust through the process so that even those are accepted.

Bringing it all together

Today’s reconstruction projects are different from those undertaken years ago. Where engineers used to design for cars and vehicular safety, they now also design for pedestrians, bicyclists and other users. We also have more regulations and best management practices in place, along with more tools to address or manage surface water runoff. A well-executed preliminary design process can make the most of these challenges and opportunities, while legitimizing your project for all your stakeholders, as was the case in Marine on St. Croix, Minnesota.

This was no ordinary County Highway project — we knew that from the start. Because Marine on St. Croix has such an incredible history meant that the design team had to craft a preliminary design process that gave residents a comfort level and a confidence that we would protect the character of their city. I truly believe what was delivered was a reasonable, sensible and responsible approach that was accepted and appreciated by the>– Frank Ticknor, Design Engineer, Washington County Public Works Department

Thanks to the CSAH 4 (Broadway Street/Ostrum Trail) Project Management Team who made this project a success!

About the Experts

Sue Mason

Sue Mason, PE, is a civil engineer and SEH regional practice center leader who helps cities and counties make sensible infrastructure decisions.  Contact Sue

Kristin Petersen

Kristin Petersen, AICP, NCI, LEED AP®, is a senior planner and engagement specialist dedicated to helping clients build projects the community loves. Contact Kristin