Mayfly - Traffic Data Archive

This site is for the distribution of traffic data collected by the IRIS traffic management system.

All response bodies are JSON arrays.

API endpoints

/mayfly/districts
Response
List of all districts in the archive
/mayfly/years
Query Parameters
district (default tms)
Response
List of years containing traffic data
Example URI
/mayfly/years?district=d3
/mayfly/dates
Query Parameters
district (default tms)
year (4 digits)
Response
List of dates with traffic data in a year
Example URI
/mayfly/dates?year=2021
/mayfly/corridors
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
Response
List of corridors configured on a given date
Example URI
/mayfly/corridors?date=20210109
/mayfly/detectors
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
Response
List of detectors with traffic data on a given date
Example URI
/mayfly/detectors?date=20210314
/mayfly/counts
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Vehicle count data for one detector on a given date
Example URI
/mayfly/counts?date=20210225&detector=363
/mayfly/headway
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Headway data (ms) for one detector on a given date
Example URI
/mayfly/headway?date=20210225&detector=363
/mayfly/occupancy
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Occupancy data (%) for one detector on a given date
Example URI
/mayfly/occupancy?date=20210225&detector=363
/mayfly/length
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Vehicle length data (ft) for one detector on a given date
Example URI
/mayfly/length?date=20210225&detector=363
/mayfly/speed
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Measured speed data (mph) for one detector on a given date
Example URI
/mayfly/speed?date=20210225&detector=363
/mayfly/espeed
Query Parameters
district (default tms)
date (8 digits; yyyyMMdd)
detector (identifier)
Response
Estimated speed data (mph) for one detector on a given date
Example URI
/mayfly/espeed?date=20210225&detector=363

Filtering

These queries can be filtered by vehicle length, headway or speed, by adding additional query parameters:

These can be used, for example, for vehicle classification. Adding length_ft_min=7&length_ft_max=19 to a query will return data only for vehicles in that length range.

Query Params
length_ft_min (Minimum vehicle length)
length_ft_max (Maximum vehicle length; non-inclusive)
headway_sec_min (Minimum headway)
headway_sec_max (Maximum headway; non-inclusive)
speed_mph_min (Minimum measured speed)
speed_mph_max (Maximum measured speed; non-inclusive)