Characterizing Bridge Functional Obsolescence Using Congestion Performance Measures Determined from Anonymous Probe-Vehicle Data

Abstract

In the last few years, anonymous probe-vehicle data has become a reliable means to evaluate travel time reliability, as well as congestion conditions along highways and major arterials. The data is collected using telematics from commercial and private cellular phones, global positioning system (GPS) devices, and onboard vehicle computers. The probe-vehicle data is commercially available in 1 min increments along spatially defined roadway segments of varying lengths. This data is being incorporated into local and statewide reports to measure congestion conditions of highway and arterial systems. This paper uses crowd-sourced anonymous probe-vehicle data to evaluate congestion duration at functionally obsolete bridge structures. The bridges selected were functionally obsolete due to poor ratings in their deck geometry as defined by the National Bridge Inventory (NBI) rating system. These deficiencies are based on a bridge’s traffic capacity as a function of its geometry and the average daily traffic (ADT). These conditions are directly expected to impact the speed and volume of traffic crossing over the bridge causing congestion. An evaluation of the travel times at bridge locations was conducted to determine if a measurable amount of congestion could be observed using probe-vehicle data. The methodologies presented in this paper were applied to 37 bridge structures in Burlington County, New Jersey. Approximately 35 million speed data records were analyzed for the 37 bridges to measure congestion. The congestion performance measures were compared with the NBI ratings to determine if congestion existed at the bridges as predicted by the NBI system. The comparison showed that a poor rating in deck geometry from the NBI system was not a strong indicator of congestion. The congestion evaluation methodologies presented in this paper were then combined with existing NBI structural ratings to demonstrate alternative bridge management strategies.