The road network of the Golden State totals more than 50,000 miles of pavement, a distance that would go round the globe more than twice. Caltrans, a federal organization that divides the state up into 12 sub-districts, is tasked with keeping this road network safe and reliable. Its core business is to constantly monitor traffic volume in the respective districts and plan the infrastructure accordingly. For years, Caltrans District 3 had relied on equipment that was cost-effective but lagged behind in terms of robustness, longevity and technological performance. The need to update a large number of sites in one project gave Kistler the opportunity to prove their competency along the whole measuring chain.
It all started in San Jose in 2016, when Dean Campbell, Senior Transportation Manager, and Gurdeep Sidhu, Electrical Engineer, met traffic professionals from Kistler at the ITS (Intelligent Transportation Society of America) exhibition. Dean Campbell reported issues with his measuring system in the district which includes the Sacramento area. Again and again, the B/L-piezo cables inserted in the road surface would break after a few years of service. Constant repair work and temporary lane closures were adding additional costs to the program as well as obstructing the flow of traffic. Also, the data management was an issue. U.S. departments of transportation – such as Caltrans – are required to disclose their collected traffic data to the public. Caltrans’ existing traffic data management system was meeting the basic requirements but had challenges with data migration into the required systems. On top, it provided no ‘real-time’ traffic information. Lastly, the existing measuring technology was limited to solely counting and classifying vehicles according to their type, e.g. passenger cars, buses, or trucks. For Caltrans to effectively plan maintenance, design roads and keep bridges in good condition, additional data on vehicle loads is critical.