Geo Week News

September 4, 2013

Is 3D imaging state DOTs' best friend?


Reliance on smart technology keeps infrastructure operating safely

Around the country, state departments of transportation are installing sensors on bridges, in roadways, and on maintenance vehicles to communicate real-time performance and weather data, allowing engineers to be proactive when it comes to problem solving.

“Most people look at a road or a bridge and never realize the technology that today’s modern transportation agencies are using to help our transportation system function at its best,” said Bud Wright, executive director of the American Association of State Highway and Transportation Association (AASHTA). “State DOTs are dramatically improving the way transportation systems, services, and information are being delivered, shared, and utilized all across the country.”

Smarter Decisions

The North Carolina Department of Transportation is using 3D imaging to dramatically improve the process of conducting annual pavement condition surveys on the state’s 16,000 miles of interstate and primary roadways. The surveys, which relied on visual assessments taken from slow moving vehicles on highway shoulders, previously took hundreds of man-hours.

Today, a contractor, uses a specially equipped vehicle that takes two sets of images as it passes over a roadway at normal highway speeds. A forward looking camera captures images of the highway while a 3D camera photographs the pavement. The pavement images are analyzed using a special software program which identifies every pavement defect.

The data is used to calculate pavement quality and identify problems such as rutting caused by heavy loads. Engineers can access all of the images and data via computer to help them make more accurate assessments and decisions. NCDOT’s Pavement Preservation and the Contract Resurfacing programs rely on this data to determine which roadways will be treated in the coming year.

“Not only is this improving the quality of the data being collected, it’s taking our pavement survey teams out of what can sometimes be a risky situation,” said Judith Corley-Lay, NCDOT pavement engineer. “This is a huge technological leap forward and I think as more states deploy it, we’ll be able to get an even better assessment of what’s occurring on our roadways, nationwide.”

Smart Maps

State departments of transportation are using a remarkable user-friendly computer mapping platform dubbed “UPlan.” This leading-edge technology combines and displays real-time information from data banks, both inside and outside transportation agencies, in the form of maps.

These multilayered displays make it easy to see the many ways proposed transportation projects will interface with the surrounding environment. Transportation projects can be created virtually to determine how they will match up with historical landmarks, population centers, and environmentally sensitive spaces such as wetlands.

To date, 14 states (WA, OR, CA, AZ, NM, NV, CO, WY, ID, UT, MT, MN, NC, and PA) have developed their own version of the platform through the Technology Implementation Group (TIG), a peer-review program sponsored by the American Association of State Highway and Transportation Officials.

Smart Bridges

Modern bridges have built-in smart technology. Hundreds of sensors are scattered throughout Minnesota Department of Transportation’s I-35W Bridge in Minneapolis and the I-10 Twin Span Bridge near New Orleans. The sensors provide data on vibration and corrosion and they can activate anti-icing systems, alert authorities when secure areas have been breached, and detect bridge strikes by anything ranging from a barge to a natural disaster.

The Nevada Department of Transportation (NDOT) Structures Division teamed up with the University of Nevada, Reno, to make the Galena Creek Bridge in Pleasant Valley a smart bridge. One of the largest “Cathedral Arch” bridges in the world, the 1,700 foot long structure has twin arches spanning 690 feet, supporting a bridge deck 295 feet above Galena Creek.

The instrumentation system on the arches allows NDOT to perform “structural health monitoring” to evaluate the day-to-day performance of the bridge over its lifetime. The real-time data, communicated via the Internet, is being supplied by strain gauges, accelerometers, and communication equipment installed while the bridge was constructed.

“This investment will allow NDOT engineers to monitor the bridge performance over their service life to help insure structural performance and effective, low-cost, long-term maintenance of these unique structures,” NDOT Director Rudy Malfabon said.

Sensors are also being added to existing bridges to extend their lifespans and detect anomalies that can be the first sign of trouble.

Engineers with the Kentucky Transportation Cabinet and other emergency responders are notified automatically when sensors measure large magnitude barge impacts on two piers of the U.S. 41 North Bridge over the Ohio River. The bridge connects Henderson, Ky., and Evansville, Ind.

In Florida, GPS sensors have been installed on a flyover bridge in Miami and the Sunshine Skyway Bridge in Tampa. Data is collected continually throughout the day on how the bridges are behaving – measuring the movement, shrinkage, and cracking of concrete. By studying variations in the data, the Florida Department of Transportation (FDOT) can detect potential problems in the concrete or the cables that hold segments of the bridge together.

“We expect the data from these sensors to tell us what the bridge is actually experiencing and, if there are any problems, the data will likely assist us in providing a more appropriate and timely solution, ” said FDOT District Structures Design Engineer Jorge A Rodriguez, P.E. “It’s too soon to assess the value of the data collected; however based on the results, we may want to add this to other bridges in the future.”

Improving Safety and Controlling Quality

The Oklahoma Department of Transportation and Oklahoma Department of Public Safety have teamed up to more efficiently process permit requests and create safe routes for commercial trucks carrying oversized or overweight loads. The Oklahoma Permitting and Routing Optimization System, dubbed OKiePROS, uses advanced GPS technology and real-time geographic and bridge information to quickly process requests on-line. Permits for oversized or overweight truck loads which used to take several days to issue, can now be processed in about 10 minutes.

Design and implementation of OKiePROS cost about $2.4 million and was funded through an appropriation by the state legislature. Last year, in its first year of operation, Oklahoma issued more than 250,000 permits, generating nearly $47 million in revenue and shattering previous state records. Most importantly, there have been no bridge strikes or accidents involving properly permitted trucks.

“With OKiePROS, we can protect the traveling public and the state’s infrastructure while making the movement of goods more efficient,” ODOT Director Mike Patterson said. “Public safety, transportation and commerce all benefit from this technology.”

The Louisiana Department of Transportation and Development has turned to smart technology to help it more easily locate compaction problems in new road construction projects. Improper compaction of construction materials can lead to costly problems such as erosion, potholes, or worse.

Louisiana DOTD is using Roller Integrated Compaction Monitoring (RICM) or intelligent compaction (IC) to measure the density of a road in real time. The system, which uses GPS technology, has the capability to measure continuous stretches of roadway, allowing contractors to find and fix problems fast.

“Our agency is constantly researching innovative technology,” said Louisiana DOTD Secretary Sherri H. LeBas. “The use of intelligent compaction on construction projects will not only contribute to cost savings, but also to the safety of the traveling public by enhancing the quality of roads.”

In an effort to minimize traffic congestion and improve safety, the Virginia Department of Transportation is in the process of deploying an Active Traffic Management (ATM) system on Interstate 66 in Northern Virginia. ATM integrates information from a wide range of sources including cameras, pavement sensors, and driver input to enhance incident management, maximize roadway capacity, and promote environmental sustainability.

Weather Data and DOTs

In Alaska, extreme winter weather can occur quickly, which is why the Alaska Department of Transportation and Public Facilities (ADOT&PF) is equipping its fleet of maintenance vehicles with instruments to gather location-specific temperature and humidity data along roadways. The data are fed to a weather modeling system, or Maintenance Decision Support System (MDSS), which can forecast when and where roadway icing is likely to occur. Deicing equipment can be mobilized more quickly and efficiently.

“This kind of technology gives ADOT&PF the ability to be in two places at once,” said Mike Coffey, Maintenance & Operations Director for Alaska DOT. “Employees can keep an eye on infrastructure during extreme cold temperatures, and we can learn how the cold impacts structures. This technology is giving us real-time information to make smart decisions, fast.”

ADOT&PF is also using smart technology on the 414-mile Dalton Highway, one of the most isolated roads in the United States. The sensors are monitoring and analyzing an enormous, moving, formation of frozen soil, rock, and ice that, if left unchecked, could block and/or damage the highway. In 2014, ADOT&PF will deploy an avalanche monitoring system that will automatically report the location and severity of a slide, enabling ADOT&PF to select the most appropriate times to temporarily delay traffic to conduct avalanche hazard reduction work.

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