Acquire model calibration data from INRIX (and optional hybrid survey w/ TLAP validation)
Introduction: The newest kid on the O-D block may be positioned to play a big role in traffic data collection in the near future. After Skycomp pilot-tested INRIX’s new Trips database product against a verified TLAP O-D dataset, Skycomp and INRIX agreed to join forces to promote and distribute this new offering. Skycomp now can take orders for INRIX Trips data directly (for data archived as far back as January 2014); Skycomp has developed the tools and expertise needed to dig into the raw INRIX databases on your behalf, to produce O-D and/or travel time profiles to fit your study needs. For borderline applications where there may be uncertainty deploying the INRIX option, Skycomp has been using a hybrid TLAP/INRIX methodology to test the accuracy of INRIX Trips and validate its use for specific study areas.
Discussion: While developing the 1-hertz TLAP service described above, Skycomp also kept an eye out for the arrival of other new technologies and tools. Skycomp was therefore intrigued to hear from INRIX that a new Trips database product was being readied for market deployment. This was to contain compilations of the millions of time-stamped “ping” records that INRIX receives every minute (for its real-time speed products) into individual historical vehicle trips, complete with start- and end-points and the intermediate waypoints. While this could potentially be invaluable for many types of transportation planning studies and model calibration needs, both macro- and (hopefully) micro-, questions were bound to arise as to its overall suitability for each application. How exactly could it be verified that the vehicles contained in the INRIX database were representative of the overall traffic stream (in my locality, on my roads)? If valid, how big would the sample sizes need to be to produce valid results? Would audiences accept models calibrated by this tool? And lastly, at what level of (micro-) granularity could it be used?
INRIX recognized that Skycomp, with its 1-hertz TLAP helicopter service, was uniquely capable of finding answers for these questions, and therefore could help clients gain confidence with this tool. “Hybrid” studies could be conducted that would use TLAP coverage to validate the INRIX outputs during pre-planned overlapped periods. Likewise, Skycomp recognized how the INRIX product was complementary to TLAP, because of TLAP’s spatial and temporal limitations. INRIX, with nothing to deploy or install and with an ability to reach back in time for archived data, would be virtually unlimited both spatially and temporally. The method would also benefit from cost efficiencies as coverage areas and time periods increased. TLAP could be deployed just for the critical heart of a large study area, while INRIX covered the rest, and for much longer periods. The granular TLAP would give users an appropriate level of confidence in the INRIX findings for the overlapped areas and periods (not to mention the other metrics contained in the imagery), and then the INRIX-only outputs could be used for the rest with an appropriate level of confidence.
To test these concepts, INRIX furnished data to Skycomp for a test O-D analysis against a TLAP dataset prepared for the Port Authority of NY and NJ, covering the New Jersey approaches to the George Washington Bridge. The TLAP / INRIX correlation was close enough that the two companies concluded a partnership agreement, whereby Skycomp would become an authorized distributor of INRIX “Trips” database product. Skycomp would conduct hybrid surveys based on client preferences, or would use its expertise working with the raw INRIX databases to produce INRIX-only output tables. (At the end of 2016, several more hybrid INRIX / TLAP analyses were nearing completion; please contact Skycomp for an update on the correlations found during the latest surveys.)