Localities Must Carefully Manage Emergence of Connected and Automated Vehicles to Reduce Risks of Exacerbating Congestion and Increasing Emissions.

A Study of the Potential Effects of Connected and Automated Vehicles on Travel in California.

Date Posted

Emissions Impact of Connected and Automated Vehicle Deployment in California

Summary Information

Although, most Connected and Automated vehicles (CAVs) are still in the prototype stage CAVs could make driving a much more pleasant task by automating most of the driving experience and easing traffic congestion. An easier driving experience could greatly improve the utility of vehicles and fundamentally reshape transportation preferences for travelers. Because of this, public authorities must begin planning for the widespread adoption of CAVs and better understand how travelers might utilize CAVs.

To advise the planning process for CAVs, a research team based at the University of California, Davis conducted  a modeling study on what the potential impacts of CAVs on transportation in California might be. To do this the team first reviewed existing literature on CAVs to inform their modeling assumptions and parameters. The team then built detailed models of a range of CAV deployment scenarios using the California Statewide Travel Demand Model Version 3.0. Specifically, the team modeled six different scenarios for CAV deployment which were:

  • Private CAVs
  • Private CAVs with Road Pricing
  • Private CAVs with Zero Emissions Vehicles
  • Shared CAVs
  • Shared CAVs with Road Pricing
  • Shared CAVs with Zero Emissions Vehicles

On the whole, CAV adoption will likely sharply decrease use of public transit and in-state air travel, and increase total Vehicle Miles Traveled (VMTs) along with associated emissions based on this modeling study. However, the use of road pricing and ZEVs mitigate some of these effects.

Overall, this study has important implications for planners and public authorities as CAVs become more widely deployed. Most notably if CAVs significantly improve the motorist experience they will also likely increase vehicle use. Thus, planners must work to mitigate negative externalities associated with CAV deployments. Planners may employ a range of strategies including:

  • Establish programs that result in driverless vehicle deployment as shared rather than privately-owned vehicles, such that they will be subject to the Clean Miles Standard and considerably reduce emissions by 2030.
  • For privately-owned CAVs, adopt a rapid timeline for vehicle electrification.
  • Develop a clear incentive system for pricing the climate impacts of travel—consider charging drivers using a GHG/passenger-mile basis.
  • Create programs that deploy CAVs to address first-last mile gaps connecting more riders to line haul transit.
  • Ensure CAV fleets include a range of vehicle types, so that demand can be right-sized and consume less energy.
  • Encourage local planning jurisdictions to work to integrate CAVs into complete streets planning, so that CAVs improve livability, safety, and comfort on surface streets.
  • Ensure local planning efforts are rooted in direct community engagement so that community members can weigh in on how the introduction of CAVs can improve accessibility and affordability to goods and services, particularly among historically underserved populations.

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