Staff and Board

Tarrell leads MCBC’s team of active transportation professionals and guides the organization as it grows, continuing to make Marin a safe and accessible place to ride a bike.

Tarrell comes to MCBC with 25 years of non-profit experience, including seven spent as Senior Director of Development for Cascade Bicycle Club, the nation’s largest statewide bicycle organization. While at Cascade, she increased the total annual fundraising income by over 500 percent, enabling the construction of a new headquarters and community gathering space, as well as a “bicycle playground” for inner-city youth.

Tarrell holds a BA in Communications from Lewis & Clark College and several advanced certificates in fundraising and non-profit development, including as a Certified Fundraising Executive (CFRE).

Sandy joined the MCBC team in July 2021.  She is responsible for sponsorship, events, and volunteer management. Please contact Sandy for sponsorship opportunities, MCBC events, bicycle parking requests, and volunteer-related questions.

Growing up an Army brat, Sandy has lived all over the United States. Moving to Marin County in 2011, she has enjoyed hiking with her dog, volunteering for Wildcare, and cycling all over Northern California. Before joining MCBC, Sandy owned a jewelry store in Sausalito for nine years, sold real estate in San Diego, managed web services for Total Gym, and worked as marketing director for a corporate relocation company.

Sandy has a degree in Art with a concentration in Photography from San Jose State University.

Liz joined MCBC in 2020 as a volunteer on the Major Donor Committee. She joined the MCBC Staff in October 2022 as the Individual Giving Director. Her responsibilities include working with our Spoke Donors and fundraising for MCBC’s programs.

Liz is an avid cyclist who has ridden in various states and countries. Before joining MCBC, Liz organized charity bike rides in Marin County for over 15 years. You will find her most often on a road bike. She also loves riding and running the amazing trails in Marin.

Liz holds a degree in Environmental Science from Sonoma State and spent a year studying in the UK. She has a Master’s in Business Administration from the University of Phoenix.

Gwen joined Safe Routes to Schools in 2008. Promoted to Director in 2015, Gwen leads SR2S’s education and encouragement programs toward making active transportation safe and accessible for all Marin children.

Her accomplishments include developing one of the first Safe Routes to Schools Teen Programs in the country. In 2016, she received the Community Partnership Award from the Marin School of Environmental Leadership in recognition of her innovative work with students.

Gwen’s dedication is inspired by her passion for healthy living. She believes that exercise is key to physical and academic success, and that it is a right, not a privilege. Gwen is often seen riding from MCBC’s Fairfax office to schools throughout Marin, or on her mountain bike, where nature invigorates her creativity for working with children.

Before joining MCBC, Gwen served as the Chairperson and Business Manager for the Ross Valley School District’s YES Theater Program, and Co-Chaired Manor School’s Winter Faire, directing volunteers to raise over $100,000 for programs that benefit children. Gwen earned a Bachelor’s in Biology from Mount Holyoke College in Massachusetts.

The son of Colombian immigrants, Dan Hernandez, is Safe Routes to Schools’ Lead Instructor. He brings over 20 years of experience in bike education from the East Bay, where he played a key role in developing REI Adventures’ national bicycling curriculum. Dan also worked with Bike East Bay, progressing from instructor to lead instructor and eventually co-manager. A certified League of American Bicyclists Cycling Instructor and Coach, he is excited to bring his expertise to Marin County.

As the youngest child in his family, the love and transformative power of cycling began early as Dan used to bike to keep up with his older siblings. His biking adventures helped him develop the necessary confidence to pursue broader horizons. A Master’s in Ecology led him to a career in conservation for ten years domestically and internationally. It was then that he began to see the power of recreation to change lives, communities, and ecosystems, as people want to protect where they recreate.

Today, he sees all the benefits of biking as spokes on a wheel: the vehicle for personal growth, joy, and smiles it brings to kids, the climate change solution, the community unifying, the pollution prevention, the parents’ dividend returned in time from not being in traffic, and multi-generational health benefits. All that moves forward with each pedal revolution. Dan is excited to contribute to this effort in every interaction with kids, both in classroom presentations and on the blacktop in bike rodeos.

Lou has been with Safe Routes to Schools since 2008. She teaches young people – ranging from 2nd graders to high school students – to safely navigate Marin’s roads, streets, and crossings. As the Teen Coordinator, Lou inspires teen clubs to promote green transportation to their student bodies, saying, “There’s nothing that compares to a teenager’s enthusiasm!”

Lou grew up riding her bike through the streets of Chicago, but was destined to live in California. You’ll regularly see her on local roads with her panniers full of Safe Routes supplies, or other times “way the heck out there” in the mountains around Fairfax.

After 13 years spent working at the University of California, San Francisco, and the Meyer Friedman Institute on heart disease research, Lou decided she would rather concentrate on the health and vitality of younger generations. Lou holds a Master’s in Cardiac Rehabilitation from the University of Wisconsin, La Crosse, and a Bachelor’s Degree in Exercise Science from Northeastern Illinois University.

A lifelong mountain biker and Marin native, Krista Hoff is deeply rooted in off-road cycling culture and committed to making trail access more equitable and sustainable for all riders. She holds a degree in Environmental Biology from Barnard College and brings over a decade of public land management experience, most recently serving as Supervising Park Ranger at Marin County Parks.

Krista has built trusted working relationships with all of Marin’s major land agencies, and she’s known for her hands-on approach, whether coordinating stakeholders or wielding a chainsaw during trail work days. Since joining MCBC in 2024, she has led the Off-Road Program’s advocacy, education, and environmental stewardship efforts. Her work supports the long-term vision of a continuous trail network from the Golden Gate Bridge to Point Reyes, while helping shape signature events like Dirt Fondo that build community on and off the trail.

Monica joined the Safe Routes to Schools team in 2014 as Bilingual Volunteer Coordinator. She promotes Safe Routes at schools with large Hispanic student bodies. Through events and competitions, Monica pursues the goal of steadily increasing the number of walkers, bikers, and carpools in Marin’s bilingual schools.

Biking is an important weekend activity for the Leifer family. Monica and her family frequently ride to Phoenix Lake. Monica’s bike is also her primary mode of transportation to the Larkspur Ferry Terminal and the Downtown San Rafael SMART Station.

Before her role with Safe Routes, Monica was Assistant Director of Media Relations at the University of San Francisco. Previously, she worked as a television reporter for the Colombian national news, as the Press Secretary to the Minister of Finance of Colombia, and as a Sales/Marketing Manager at Latin Finance Magazine in Miami, Florida. Monica holds a Bachelor’s Degree in Communication Studies and Journalism from the Pontificia Universidad Javeriana in Bogota

Cooper joined MCBC in the summer of 2021 as the Volunteer Coordinator for Safe Routes to Schools. Cooper is passionate about building community with parents, students, and educators in Marin County. Cooper now manages the Cory’s Ride Program.

In his day-to-day activities, Cooper works with Cory’s Ride students in the Canal neighborhood, Novato, and Marin City.

Cooper is an avid cyclist and lover of all things two-wheels. In his free time, he can be found riding his road or mountain bike on the myriad of great roads and trails throughout the county. Before joining MCBC, Cooper worked for Backroads, selling cycling and hiking adventure trips. He is also an active coach with the National Interscholastic Cycling Association (NICA) and spends time coaching and mentoring high school athletes.

Cooper holds a BA in Business Administration from the University of Baltimore.

Warren joined MCBC in early 2021. Serving as the Policy & Planning Director, he is responsible for coordinating advocacy campaigns associated with the Streets & Roads Program, aiming to complete the North-South and East-West Greenways and to make bicycling and walking in Marin safer and more convenient.

Warren sees widespread bicycling as a key part of addressing issues of public health, economic justice, and climate change. He is a car-free commuter, giving up his keys in 2015. Since moving to the Bay, he has taken up recreational riding and has ridden hundreds of miles on Mount Tam and in the Marin Headlands.

An East Coast native, Warren has experience as a local organizer, coach, and mediator working in restorative justice. He moved to California to earn a master’s degree in Urban and Regional Planning from UCLA and, after receiving his degree, served as a transportation planner for a private firm developing transit and bike/pedestrian projects across the Bay Area.

Katy started with Safe Routes to School in September 2022 as an Instructor and stepped into the Education Coordinator role in November, replacing long time Education Coordinator Peggy Clark.

Katy has been teaching elementary students for 15 years in Marin County and in the East Bay. She is an advocate for experiential learning and for teaching habits that promote public health and fitness. She believes that by learning cycling early, children will have the skills and enthusiasm to ride in many situations in life.

Katy will be scheduling Safe Routes’ indoor and outdoor safety education provided to 10,000 2nd through 12th grade students at 50 Marin schools annually. Her focus will be fostering connections with teachers to bring the Safe Routes team, bikes, and courses for students to hone their skills and practice following the rules of the road.

Leading up to teaching in the Bay Area, Katy worked in various roles, including an Art and Sports volunteer teacher to children in Belize. She loves cycling challenges such as sprint triathlons and the 3 Bears ride. She obtained her League Certified Instructor certificate in 2011. She grew up in the San Francisco Bay Area and lives in San Rafael with her husband and son.