The nine-county Bay Area region's traffic accounts for about 80 percent of all the congestion in Northern California. 40 percent of that congestion occurs within Alameda County. Supervisor Haggerty has taken a leading role in improving transportation throughout the region. With traffic traveling through Alameda County projected to double by 2030, his goals include making long-needed improvements in major travel corridors including I-580 in the Tri-Valley, one of the most congested roads in the Bay Area; and expanding and enhancing transit service. Scott is currently working to ensure the BART (Bay Area Rapid Transit) extension to Livermore is completed, and also has a key role in an ongoing effort to extend BART to San Jose.

With regional transportation and infrastructure issues a priority, Supervisor Haggerty is active on a number of boards and commissions and has extensive experience in this policy area. He chairs the Metropolitan Transportation Commission (MTC), the agency responsible for allocating state and federal funds to regional transportation projects; related to MTC, he chairs the Bay Area Toll Authority (BATA) which administers the toll program for the Bay Area's seven toll bridges including operations, maintenance and management, seismic retrofit and capital improvements; he is also a member and former chair of the Bay Area Air Quality Management District (BAAQMD) which oversees regional air quality regulations and programs. At the county-wide level, Scott serves as vice chair of the Alameda County Transportation Commission (ACTC), a consolidation of the functions and services of the Alameda County Congestion Management Agency (CMA) (which he formerly chaired) and the Alameda County Transportation Improvement Authority (ACTIA) (served as vice chair) and the Alameda County Transportation Authority (ACTA) which was formed to oversee projects funded through voter-approved Measure B dollars; member and former chair of the Altamont Commuter Express Joint Powers Authority (ACE); chair and member of the Livermore-Amador Valley Transit Authority (LAVTA) which operates the WHEELS bus service in the Tri-Valley; and member of the Board of Supervisors Transportation & Planning Committee.

At the national level, Scott represents Alameda County at the National Association of Counties (NACo) serving as vice chair on its Large Urban County Caucus. He just completed two terms as chair of the Transportation Steering Committee and also formerly served as vice chair of the Rail and Transit Subcommittee. NACo's membership totals more than 2,000 counties representing 80 percent of the U.S. population.

In addition to his leadership in the transportation arena, Supervisor Haggerty places strong priorities in the field of public safety.  Appointed by then-Governor Pete Wilson, Scott formerly served on the California State Seismic Safety Commission. He serves on the board of the East Bay Regional Communications System Authority (EBRCSA) established to provide a fully inter-operable communications system to all public agencies within Alameda and Contra Costa Counties. He is a member of the Alameda County Collaborating Agencies Responding to Disasters (CARD) Board of Directors. Scott formerly chaired the Alameda County Board of Supervisors Public Protection Committee and has been very active on paramedic and trauma issues.

Scott's appointment to other boards and commissions as the representative for Alameda County include: member and former President of the Association of Bay Area Governments (ABAG); East Bay Regional Park District County Liaison Committee; Local Agency Formation Commission ((LAFCO); and the Tri-Valley Transportation Council (TVTC). Appointed to the Commission of the Oakland-Alameda County Coliseum Authority in 2001, Scott currently serves as chair for the second time.

Supervisor Haggerty was raised in Fremont and now resides in Dublin with his family.