Title: Telematics data to analyse the real-world efficacy of clean air zones (CAZ), the crossroads of air quality improvement and decarbonization strategies 
Farzaneh Jajarmi, Omid Ghaffarpasand, Junjun Xiang, and Francis D. Pope
School of Geography, Earth, and Environmental Sciences, University of Birmingham, Birmingham, UK
October 2025

## Overview

This repository contains telematics trajectory datasets collected from urban vehicles within the city of Birmingham, UK, for the years 2016, 2018, 2021, and 2022. The data have been formatted and cleaned for reproducible research and are provided as UTF-8 encoded CSV files. 

## File List

- Year_2016.csv
- Year_2018.csv
- Year_2021.csv
- Year_2022.csv

## Data Description

Each file includes the following variables:

- **Road Type**: Road class or segment type. This dataset distinguishes three road types: minor roads encompass secondary and tertiary segments; major roads include motorways, primary, and trunk routes; and residential roads are represented separately.
- **LATSTA**: Latitude of the starting point of the polyline segment.
- **LONSTA**: Longitude of the starting point.
- **LATSTO**: Latitude of the end point of the polyline segment.
- **LONSTO**: Longitude of the end point.


The core telematics variables are repeated for different day/hour windows:

- **Day Codes**: 
    - D0 = Sunday
    - D1 = Monday
    - D2 / D3 / D4 = Tuesday/Wednesday/Thursday (Wednesday and Thursday assumed similar to Tuesday, as discussed in the body of the associated paper)
    - D5 = Friday
    - D6 = Saturday
- **Hour Codes**: Denote beginning and end of interval (e.g., H0.6 = 00:00-06:59, H7.8 = 07:00-08:59, H9.11 = 09:00-11:59, etc.)

Each day/hour window has three variables:
- **v_***: Mean segment speed (km/h)
- **a_***: Mean segment acceleration (m/s^2)
- **VSP_***: Vehicle Specific Power estimate (kW/ton)
- **NOx_***: NOx Emission Factor (g/km)
- **CO2_***: CO2 Emission Factor (g/km)

Variable example: `v_D2.3.4H7.8` = mean speed for Tuesday/Wednesday/Thursday in 07:00-08:59.

## Data Cleaning and Formatting

- All files have been stripped of non-essential identifiers (segment codes, X columns).
- Column order is consistent across years: core attributes first, followed by telematics variables sorted alphabetically.
- Missing values are encoded as empty cells.
- All datasets saved as comma-separated values (CSV), UTF-8.

## Additional Notes

- Data privacy and licensing: Only anonymized, aggregate segment-level information is provided. No individual trajectory or PII is included.
- The day assignments for Wednesday and Thursday are described further in the main publication.
- 'Seglen' refers to segment length in meters, useful for spatial analyses.

## Citation

If using these datasets, please cite:
[Provide associated paper DOI or reference]

For further questions, contact: Prof Francis D. Pope through f.pope@bham.ac.uk