Infrastructure of all types throughout the United States is aging. Organizations need to increase their inspections, repairs, and maintenance programs to keep this infrastructure viable in a growing economy. In some cases, existing infrastructure doesn’t adequately meet the requirements of today’s equipment. One such example is the Virginia Street overpass along I-65/I-70 in southeast Indianapolis, Indiana.


On February 22nd, 2013, an oversized truck collided with the Virginia Street overpass on I-65/I-70 causing a support beam to split. Due to the risk to the integrity of the structure, INDOT responded swiftly, engaging Continental Mapping to complete a mobile lidar and mapping project for the site. Time was of the essence to provide survey data to INDOT’s engineers so that a design for a repair could be quickly made. This bridge had been closely watched by INDOT for some time given its limited clearances and numerous reported strikes. A local university had even mounted a camera on the bridge to document the dozens of strikes to the bridge both minor and major.


Within a few days of notification of the devastating collision, Continental Mapping mobilized its Riegl VMX-250 mobile lidar system to collect mobile lidar data along the primary route and all cross roads. The mobile unit collected over 15 lane miles of highway, including 30 bridges. In addition, aerial imagery was also rapidly collected to provide aerial imagery of the entire corridor but also to provide stereo-imagery for mapping to the right-of-way beyond the hard surfaces covered by the mobile lidar.


Upon collection, Continental Mapping immediately provided INDOT and its design consultants with vertical clearance information. This information was of utmost importance for the design teams to begin evaluating design options such as raising the bridges or dropping the grade along the primary roadway. Clearance information was also creatively packaged into a ‘map book’ so that all involved in the project could visualize clearance information on the orthos, in plan and profile view and integrated with ground-based photography. A sample of the map book is shown to the left.


Fusing data from all sources, mobile lidar, field survey and aerial imagery, was of utmost importance for the success of this project. Mobile lidar provided very high accuracy data along all roadway surfaces as well as DTM under the bridges. Aerial imagery provided high accuracy mapping beyond the hard surfaces to the right-of-way as well as the ability to generate orthophotos for all participants to have current imagery of the entire project corridor. Field survey provided project control to tie all datasets together but also supplement data collections where mobile lidar or aerial imagery was obstructed. 


The project team hybridized the mobile lidar and imagery to complete planimetric mapping throughout the corridor and delivered a DTM, orthos, photolog imagery, and a calibrated point cloud. Vertical clearances were also calculated for each lane of each bridge. Detailed modeling data were also delivered for areas under the overpasses.


On several occasions throughout the design process, INDOT engineers or their sub-consultants came back to Continental Mapping for more information. As an example, engineers determined that they needed clearance information for all the large signage throughout the corridor. Accessing this information did not require a return trip to the field but rather accessing the point cloud data and deriving those measurements. Continental Mapping was able to address this request in a very timely manner.

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This is an example page from the map book deliverable provided by Continental Mapping for the INDOT South Split project.


Continental Mapping holds a master contract for On-Call Aerial Mapping Services with INDOT.