A video camera setup provided important details on repeated collisions with interstate overcrossings.
Repeated instances of large, fast-moving vehicles colliding with bridges that cross multiple interstates is certainly cause for alarm among transportation officials and motorists – especially those involved in the collisions. Yet that’s precisely what was happening in Indianapolis, Ind., in an area known as the South Split where Interstate 65 and 70 meet. Officials at the Indiana Department of Transportation (INDOT) knew the collisions were occurring but not why, how often and how severely.
Circumstantial data from years past suggested an increasing number of oversize vehicles – often semi-trucks hauling large machinery or equipment on flatbeds – were striking four bridges in the South Split. In most cases these were not catastrophic collisions. Rather, the flatbed payload or the trailer being towed would just nick – relatively speaking – the overpass. But it seemed to be happening more often than in previous years.
The four bridges in the South Split have vertical clearances ranging from 13’11” to 14’6”. INDOT officials documented more than 400 collisions since 1999 and recent data showed the number was on the rise. INDOT officials decided to lower the South Split roadbed to reduce the number of strikes. But they also wanted to find out for sure what was going on. So last fall INDOT, with the help of Purdue University, installed a camera on the Virginia Avenue Bridge.
“The impetus for the project was the increasing frequency and severity of oversize vehicles hitting these low bridges,” explained Will Wingfield, Communications Director of INDOT. “We were exploring different low cost measures to reduce that.”
The camera was a simple solution that used off-the-shelf technology. INDOT did not have to custom build anything. The parts were all readily available and they were all affordable. And once installed, the camera produced dramatic footage.
“One of the things that made this successful was that we were using consumer technology,” Wingfield said. “This was a camera recording 24/7 to which was attached a solar panel to provide power and a cell connection to provide network access. The camera was not continuously recording. Rather, an accelerometer started recording the moment something hit the bridge.”
Once the accelerometer activated, the camera would send a clip of video and a text message to INDOT personnel, including bridge engineers, noting that there had been significant movement of the structure.
The camera monitored the Virginia Avenue Bridge for one year. In that time, it recorded dozens of strikes. On the South Split roadbed project webpage, INDOT began posting clips of the impacts. Tractors, construction equipment, car transport trucks, trucks towing other trucks – all manner of oversize loads were striking the bridge and getting caught on camera.
Wingfield said there are a number of reasons the loads were exceeding the posted bridge height. Typically, he said, people think they’ve properly secured their loads when they actually have not.
“We advise people to measure and secure loads and obtain the proper permits,” Wingfield said. “One reason for measuring and securing is many of these vehicles have hydraulic arms and when they hit bumps in the road the arm may actually raise slightly over time.”
In early September, the camera’s time on the bridge came to an end. The simple solution had served its purpose. INDOT had the data it needed as it began the process of lowering the roadbed and the agency had effectively raised public awareness about a significant safety issue.
“The camera served as an important tool for us,” Wingfield said. “It allowed us to identify the types of vehicles that would strike the bridge on a regular basis.”
The videos proved popular among INDOT’s social media fans and with area media outlets. So much so, in fact, that INDOT has brought more cameras with it to the actual roadbed construction – five of them, to be precise.
“We have five time-lapse cameras mounted to monitor construction progress,” Wingfield said. We’re sharing information through social media and the traditional news media.”
Some simple, cheap technology available just about everywhere helped INDOT address a public safety problem and create a solution. And now, for people who are so inclined, that solution is under construction and can be viewed in time lapse from the comfort of your computer screen.