A Cleaner Transition: Why CAT Should Expand Using Diesel-Hybrid Buses
In recent years, Charlottesville Area Transit (CAT) and Charlottesville City Council have truly accelerated the City’s transportation justice and climate change mitigation practices. Just this year at C3, we’ve written about how CAT’s equity-focused ten-year Transit Strategic Plan (TSP), authorized in June, sets out a vision for a transit system that meets residents where they’re at with greater frequency and dignity [1]. We also celebrated when City Councilors, informed by their Alternative Fuels Study [2] and community advocacy by organizations including C3 [3], voted in February to abandon fossil fuels altogether as a fuel choice for buses [4], proceeding only with Zero Emission Buses (ZEBs). It is clear that Charlottesville area residents are fortunate enough to have a visionary team of decision-makers at the helm of our transit planning, ready to meet the challenges posed by climate change.
Now, a new opportunity has presented itself for City Council and CAT to prove themselves as visionary leaders for climate justice in our community! In this blog post, we identify and discuss a choice before them: to investigate the purchase of newer diesel hybrids instead of conventional diesel-only buses during the transition to ZEBs.
Why do we have to “transition to ZEBs”?
The path to a zero-emission future is a marathon, not a sprint. While C3 has identified ZEBs such as battery-electric buses (BEBs) as the ideal long-term type for the Charlottesville area [5], it also requires infrastructure investments and route design to accommodate the different needs for these alternative, cleaner fuel types [6]. Coupled with the budgetary considerations for purchasing new equipment [7], this means that replacing the current fossil-fueled bus fleet with new technologies will take time, with CAT’s Director Garland Williams having identified calendar year 2027 as the point after which no more diesel-only buses will be purchased [8].
At the same time, CAT has identified increased frequency and expanded operating hours as a top priority for its service improvements, requiring the purchase of additional buses to allow for increased frequency across all routes [9]. What this means, under the current plan, is that CAT’s fleet of diesel buses is expanding by nearly 50%, from 40 buses to 58 [10].
It is important to note, here, that while no more diesel buses will be purchased from 2027 onward, Charlottesville will still have purely diesel-powered buses emitting greenhouse gases into our community until 2039, at the very earliest, and potentially even later.
Transition is not Binary, and Technology Evolves
As we navigate the path to zero-emission transportation, it's crucial to use transitional technologies that can significantly reduce our environmental footprint right now as well as planning ambitiously for future, total decarbonization. Here is where the new opportunity lies, in a pivotal choice for City Council and CAT: instead of increasing the number of conventional diesel buses by almost 50%, we can and must consider the very realistic and impactful option of switching to reliable diesel-hybrid buses as we move towards an all-electric fleet.
Source: Lukas 3z, Creative Commons Attribution-Share Alike Attribution-Share Alike 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.
Diesel-hybrid buses offer substantial benefits when compared to traditional diesel buses [11], [12]:
Immediate Reduction in Emissions: Diesel-hybrid buses produce far fewer pollution than conventional diesel buses. One study showed that hydrocarbon emissions were reduced by 33%, nitrous oxide by 44%, and particle emissions by 51% [13]. This means cleaner air in Charlottesville, with reduced health risks and immediate and tangible environmental benefits.
Enhanced Fuel Efficiency: Diesel-hybrid buses are significantly more fuel-efficient than their diesel counterparts, which translates to cost savings for CAT, savings can be reinvested into furthering sustainable initiatives.
Technological and Operational Benefits: Hybrid buses offer improved performance, leading to a smoother, quieter rider experience and less wear and tear on the vehicles.
Financially Feasible Transition: Diesel-hybrid buses require less upfront investment compared to ZEBs and no new investment for charging infrastructure updates.
Demonstrating Leadership in Sustainability: Switching to diesel-hybrid buses sends a strong message from CAT and City Council to the community and stakeholders that our leadership is deeply proactive and adaptable in addressing environmental challenges.
Why haven’t we considered this before?
Hybrid buses have taken years of technological advances to reach this state of reliability and low operating cost [14]. As an early adopter of hybrid buses, after 6 years of reliable operability, CAT began to have issues with some of its early-technology hybrid buses, dissuading the agency from pursuing diesel-hybrid as a primary fuel type [15]. However, at a recent exploratory trip to see the hydrogen-powered buses used by Champaign-Urbana Mass Transit District (MTD) in Illinois, City Councilors and CAT staff were surprised to discover that after a similarly rocky start in transitioning from diesel to hybrid, MTD has now been using diesel-hybrid buses for years, with exponentially increasing success and reliability [16].
Source: MTD diesel-hybrid bus photographed by Joey Cao, Creative Commons https://creativecommons.org/licenses/by-sa/4.0/deed.en
In subsequent communications with C3 staff [17], MTD leadership shared its performance data across bus types. The surprising result was that the newest diesel-hybrid buses massively outperform not only their conventional diesel counterparts but also their early diesel-hybrid forebearers, across fuel economy, cost per mile, and average miles driven. While MTD initially experienced similar problems to CAT with their earlier hybrid buses, after pursuing alternative, more modern diesel-hybrid options, they now operate a fleet of over 100 hybrid buses that is more reliable, more cost-effective and - crucially - more environmentally friendly than a diesel fleet could hope to be.
While it is important to incorporate lessons learned from CAT’s own experience, it is also vital that City Council and CAT stay flexible and adaptable, informed by science and peer agencies alike. MTD’s lessons learned could propel CAT into an even more climate-forward position, allowing us to achieve greater milestones even earlier.
Asked what kind of leader he would like to be remembered as upon his election in January this year, Mayor Juandiego Wade expressed the hope that people would say, “He really listened, and he acted on what he listened to. [18]”
By listening to both community advocates and peer leadership in other communities, switching to diesel-hybrid buses, and availing of every tool in the climate toolkit to serve both future and current residents, City Council can set in stone a legacy of inspired, progressive leadership.
SOURCES
[1] Sadhbh O’Flynn (2024), “CAT’s 10-year Transit Strategic Plan: Advancing Transportation Justice”. Available at: https://theclimatecollaborative.org/blog/2024/6/13/cats-10-year-transit-strategic-plan-advancing-transportation-justice
[2] Charlottesville City Council (2024), “City Council Work Session - Alternative Fuels Study - February 27, 2024”. Available at: https://charlottesvilleva.portal.civicclerk.com/event/2073/files/attachment/4778
[3] CBS19 (2023), “C3 Petition Calls on City Council to Act Regarding Cleaner Transit”. Available at: https://www.cbs19news.com/story/49548003/c3-petition-calls-on-city-council-to-act-regarding-cleaner-transit/
[4] Maria Duster (2024), “Charlottesville Moves Forward with Zero-Emission Fuel Choices”. Available at:
[5] Community Climate Collaborative (2023), “Alternative Fuels for Transit Buses: What’s the Best Option For Your Transit Agency? (Vol. 1)”. Available at: https://theclimatecollaborative.org/alternative-fuel-buses-report
[6] FTA & Center for Urban Transportation Research (2023), “Procuring and Maintaining Battery Electric Buses and Charging Systems – Best Practices”. Available at: https://www.transit.dot.gov/sites/fta.dot.gov/files/2023-08/FTA-Report-No-0253.pdf
[7] Charlottesville Area Transit (2024), “Chapter 5: Financial Plan”. Available at: https://www.charlottesville.gov/DocumentCenter/View/12164/CAT-FINAL-TSP-Chapter-5?bidId=
[8] Charlottesville Area Transit (2024), “CAT Transit Strategic Plan: May 21, 2024 Virtual Public Meeting”. Available at: https://www.youtube.com/watch?v=SFz-g0TGB_4, minute mark 26:12
[9] Charlottesville Area Transit (2024), “Chapter 4: Implementation Plan”. Available at: https://www.charlottesville.gov/DocumentCenter/View/12163/CAT-FINAL-TSP-Chapter-4?bidId=, pp.(4-4)-(4-5)
[10] Charlottesville City Council (2024), “City Council Work Session - Alternative Fuels Study - February 27, 2024”. Available at: https://charlottesvilleva.portal.civicclerk.com/event/2073/files/attachment/4778, slide 41
[11] World Resources Institute (2019), “Financing Electric and Hybrid-Electric Buses”. Available at: https://files.wri.org/d8/s3fs-public/financing-electric-hybrid-electric-buses_0.pdf
[12] Email communication between C3 and Karl Gnadt, Managing Director/CEO Champaign-Urbana Mass Transit District (MTD)
[13] Guangju Xu et al (2017), “Study on emission characteristics of hybrid buses under driving cycles in a typical Chinese city”. Available at: https://journals.sagepub.com/doi/pdf/10.1177/1687814017728238
[14] Email communication between C3 and Karl Gnadt, Managing Director/CEO Champaign-Urbana Mass Transit District (MTD)
[15] Sean Tubbs (2024), “Area delegation travels to Illinois to tour hydrogen production used by Champaign-Urbana Mass Transit District to power a dozen buses”. Available at: https://infocville.com/2024/06/14/area-delegation-travels-to-illinois-to-tour-hydrogen-production-used-by-champaign-urbana-mass-transit-district-to-power-a-dozen-buses/
[16] Sean Tubbs (2024), “Area delegation travels to Illinois to tour hydrogen production used by Champaign-Urbana Mass Transit District to power a dozen buses”. Op cit.
[17] Email communication between C3 and Karl Gnadt, Managing Director/CEO Champaign-Urbana Mass Transit District (MTD)
[18] Sonia Montalvo (2024), “Just Call Me Juan: Mayor Juandiego Wade Takes the Helm”. Available at: https://vinegarhillmagazine.com/76271-2/