Pedal Power: How two engineering Ph.D.s founded the Tartan Bike Project

Carnegie Mellon has a strong cycling culture, with many students, faculty, and staff biking to campus or simply riding around Pittsburgh for exercise and recreation. In recent years, the university has invested in making campus more accessible and safer for cyclists and pedestrians alike with new policies, maps and bike paths, infrastructure, and dismount zones. Still, for some students, something core was missing.

For Kenedy Sánchez and Hosea Santiago-Cruz, that “something” missing was community. They founded the Tartan Bike Project (TBP) at CMU to change that.

The two Ph.D. researchers in the Department of Civil and Environmental Engineering (CEE) are members of the same lab and share an advisor: Greg Lowry, department head and professor of civil and environmental engineering. As friends and lab mates, they both discovered that the other was an avid cyclist and had been involved in student-led bike co-ops during their undergraduate years​​—Sánchez at University of Texas at Austin and Santiago-Cruz at the University of Puerto Rico at Mayagüez.

 

The point of TBP is to offer affordable, sustainable transportation options and to build community. It’s for everyone.

Kenedy Sánchez, Ph.D. Candidate, Department of Civil and Environmental Engineering

At UT Austin, Sánchez learned how to fix bikes and found a new community that became central to her life and her identity. Before college, Santiago-Cruz learned how to repair bikes by helping out in his parents’ bike shop as a teenager. As they began having discussions about how to make a bike shop happen at CMU, they both got more excited about the concept.

“We didn’t just want to sell and repair bikes. We wanted to be a source of community and activism,” said Santiago-Cruz.

Joe Moore, assistant teaching professor of civil and environmental engineering, introduced Sánchez and Santiago-Cruz to Rocky Cristobal, the owner of Kraynick’s Bike Shop in Pittsburgh. Cristobal donated some tools and equipment to get them started. Sánchez and Santiago-Cruz decided to test the appetite for their idea at CMU with a pop-up event at the Fence offering free bike repairs. They didn’t know what to expect.

“People just started lining up,” Sánchez said. “We were thinking maybe we’d see five people show up, but we helped more than 40 people.” In addition to the in-person demand that day, Sánchez and Santiago-Cruz had the forethought to gather some data about interest in an on-campus bike shop. With those numbers in hand, as well as some prospective locations, they proposed the Tartan Bike Project to the Graduate Student Assembly and were awarded $20,000 to seed its launch as a student organization.

Setting up shop was about much more than securing the funds, though. Sánchez and Santiago-Cruz spent months meeting with local biking organizations and advocates, as well as campus partners including Michelle Porter and Karen Brooks from CMU Parking and Transportation, to ensure the project was thoroughly planned and fully supported.

Today, TBP rents and sells bikes, as well as offers bike repairs, education, social rides, community outreach, and advocacy for the entire CMU cycling community. Currently, the bike shop’s co-founders are focused on ensuring the sustainability and longevity of the project, even after they finish their Ph.D. programs and move on from CMU. As he approaches the end of his time at CMU, Santiago-Cruz said he decompresses from his research by popping down to TBP’s physical home in the Gates Garage.

“Being in the bike shop and helping people—that fills me up,” he said. “It’s student-oriented and student-led. That feels good and we want to preserve that.”

While the Tartan Bike Project grew out of the College of Engineering and many engineering students are involved, both Sánchez and Santiago-Cruz remark that it has grown organically into a resource for all of CMU, with volunteers and participation from across the university.

“The whole point of TBP is to offer affordable, sustainable transportation options and to build community. It’s for everyone,” said Sánchez.

From the bike lane to the lab

As researchers, Sánchez and Santiago-Cruz have made significant contributions in the sustainability field as well.

Santiago-Cruz’s Ph.D. work has centered on researching methods of destroying per- and polyfluoroalkyl substances (PFAS)​​, commonly known as “forever chemicals.” They earned that moniker through their persistence as environmental pollutants that are notoriously challenging to remove from soil and water and to subsequently destroy.

“We’re finding ways to better remove PFAS and then break them down,” said Santiago-Cruz, whose research has explored ways to use ultraviolet light to break the chemical bonds of different types of PFAS. Currently, water treatment plants are focused on the removal part of the equation, using separation and filtration technologies that can effectively remove PFAS from water. However, that process creates solid wastes that then must be managed, and none of those management options are ideal.

“That’s where my research comes in. How can we treat these materials that we’re using to separate the PFAS in the water so that we’re actually breaking down all those bonds to make it safer?” said Santiago-Cruz. While he notes that there are still many open questions in the science and scalability of PFAS solutions, his research is a step in the right direction.

Sánchez’s initial research focused on nano-enabled agriculture, using nanoparticle systems to improve antibiotic delivery in citrus trees. Her project concerns Florida orange trees in particular, which have been devastated in recent years by citrus greening disease, a bacterial infection spread by the Asian Citrus psyllid. Sánchez’s role in the project—which was a collaboration with Purdue University, University of California Riverside, and University of Florida—involved analyzing how nano-antibiotics move in citrus trees after delivery, and how much of the antibiotic was reaching the tree’s phloem/inner bark.

“We found that with our nanocarrier, we were able to target the phloem, the site of disease,” said Sánchez. “Not only were we able to deliver these nanocarriers to the phloem through the leaves, but we can also do it through the trunk, through these openings called lenticels. That was novel; no one has done that before.”

The project’s field trial in Florida resulted in higher fruit set and crop yields—nearly eight times greater—compared to non-nano-antibiotics.

“What makes this cool is that nano-antibiotics can be scaled up into a real solution that can be used by farmers,” said Sánchez.

We didn’t just want to sell and repair bikes. We wanted to be a source of community and activism.

Hosea Santiago-Cruz, Ph.D. Candidate, Department of Civil and Environmental Engineering

Future work in this area could improve the phloem-loading efficacy of various treatments and nutrients, potentially reducing the amount of chemicals needed to achieve desired results and, in turn, reducing pollution such as nitrogen runoff. Sánchez’s current research is focused on how nanoparticles interact with plant cell walls.

Amidst the success of her research at CMU and the potential impact it could have in the agricultural industry and in society, Sánchez has also developed a greater interest in public policy and science communication.

In that sense, her experiences co-founding the Tartan Bike Project with Santiago-Cruz and participating in bike advocacy in Pittsburgh have been instructive, giving her insight into how an idea gains traction, working with stakeholders and civic leaders, gathering feedback, and focusing on local impact. For Sánchez, that approach holds true whether you’re fighting for a new bike lane or explaining why an engineering solution will be beneficial.

“Our solutions should lift up our community, and to do that we need to meet people where they are and be able to both listen to what they want and communicate why our ideas may help,” she said.