Autonomie

POLARIS (Planning and Operations Language for Agent-based Regional Integrated Simulation) is an open-source transportation simulation framework developed by Argonne National Laboratory. It enables dynamic traffic assignment and high-resolution agent-based simulation of urban mobility patterns. POLARIS can generate realistic traffic flows, vehicle trajectories, and travel demand patterns for entire metropolitan regions.

Its outputs (traffic volumes, speeds, and vehicle routing) can be directly linked to emission estimation tools like AMBER and used in air quality assessments.

AMBER (Automated Model for Beneficial Evaluation of Roadway air quality) is a tool developed by Argonne National Laboratory to estimate vehicular emissions in urban and suburban road networks. It uses traffic data (such as vehicle flow, average speed, and fleet composition) to calculate hourly emissions of air pollutants such as NOx, CO, PM, among others.

Emissions are spatially distributed by road segment and can be exported in formats compatible with atmospheric dispersion models such as AERMOD.

Autonomie is a vehicle simulation environment, also developed by Argonne. It allows modeling the energy performance and emissions of vehicles with various technologies (internal combustion, hybrids, electric), in response to defined driving cycles (e.g., FTP-75, WLTP, or real GPS data).

With Autonomie, detailed emission factors (as functions of speed, acceleration, and vehicle type) can be generated and used in traffic models like AMBER.

The integrated workflow among POLARIS, AMBER, and Autonomie includes the following steps:

1. POLARIS simulates traffic dynamics in the study area, generating traffic volumes, speeds, and vehicle trajectories per road segment and per time step.
2. Autonomie is used to simulate emission factors by vehicle type and operating condition (speed, acceleration).
3. The emission factors from Autonomie are fed into AMBER, which applies them across the network generated by POLARIS.
4. AMBER calculates hourly emissions per road segment, considering traffic variation and fleet composition.

To model atmospheric dispersion of traffic emissions, AMBER outputs must be formatted for AERMOD input. The typical process is:

1. Define the road network and area of interest.
2. Simulate traffic with POLARIS to generate hourly flow and speed data.
3. Use Autonomie to generate vehicle-specific emission factors.
4. Use AMBER to compute hourly emissions by road segment.
5. Convert road segments to line source compatible with AERMOD input.
6. Apply hourly emission profiles using EMISFACT or TEMPORAL files.
7. Run AERMOD using meteorological inputs processed with AERMET.

• MOVES (EPA): an alternative to Autonomie for emission factor generation in the U.S.
• GIS tools (QGIS, ArcGIS): for mapping and exporting road segments.
• AERMET/AERSURFACE: for preparing meteorological input data for AERMOD.
• Python or R: useful for automating traffic/emission processing and format conversion.

The integration of POLARIS, Autonomie, AMBER, and AERMOD enables:

• High-resolution spatial and temporal emission estimates.
• Emission factors aligned with the local vehicle fleet and operational behavior.
• Evaluation of urban policy scenarios (fleet electrification, traffic restrictions, dynamic routing).
• Detailed air quality assessment of vehicular pollution in urban environments.
• Support for decision-making on transportation planning and environmental health.