Transportation safety is a driving force within Departments of Transportation. Kansas ranks 16th in the quality of life for its transportation infrastructure due in part to its aggressive Kansas Highway Safety Improvement Program.
So when KDOT needed a surface model for a pavement rehabilitation project along 7.2 miles of heavily traveled I-35 in Johnson County, the data had to be obtained in the safest manner possible and as quickly as possible. TREKK used its in-house mobile LiDAR to create a DTM of the existing pavement surface and 3D features, such as overhead signs, crash barriers and bridges, to assist in making recommendations for pavement overlay and corrective actions for drainage. We obtained the survey-grade data in 3.5 hours, collecting 12GB of LiDAR data and 15GB of time-stamped, geo-referenced 360 degree HD images. The final RMSe accuracy was 0.014′ to 109 control points.
“KDOT specifically requested the use of mobile LiDAR scanning because of the need to quickly obtain accurate pavement cross slope data for the corridor, as well as overhead signs and bridge structures, drainage inlets, barrier, and guardrail,” said HDR Roadway Design Engineer, Kyle Schomaker. “The project called for a minimum 4.5- inch overlay of the existing pavement. It was critical to be able to evaluate the existing pavement cross slope conditions, guardrail heights and existing vertical clearances to ensure that the final overlay slopes would be within FHWA tolerances in order to receive federal funding for the project. The project schedule was extremely compressed and required the TREKK team to mobilize rapidly for the scan and expedite the post-processing of the data. Additionally, because of the tight schedule, it was requested that the data be delivered in pieces so that the evaluation and recommendation process could take place on a concurrent track. TREKK was able to accommodate this and, ultimately, both KDOT and FHWA were happy with the quality of the results and the timeliness of the deliverables.”
Part of TREKK’s IMPROVING LIVES philosophy is a proactive understanding that every highway situation a land surveyor faces has the possibility of changing a life forever. A surveyor’s workplace is always moving. It is only natural that the tools in the surveyor tool box must be dynamic ones. That tool for design-grade transportation is Terrestrial Mobile LiDAR Surveying (TMLS). Traditionally, land surveyors often spend time by roadsides, close to the danger of fast moving traffic. The power in TMLS is that it moves with the traffic, oblivious to the traveling public.
“Using mobile LiDAR data methods instead of conventional survey methods allowed for a safer collection process on one of the most heavily traveled corridors in the Kansas City region,” said TREKK Associate Partner and Transportation Lead, Tawn Nugent. “The density of the LiDAR data was critical in determining the required pavement resurfacing quantities due to the variable overlay thickness. This level of data is only feasible with LiDAR technology.”