Application #3: Sight Distance and Older Drivers Among states, Iowa has the second highest proportion of older drivers. Highways are designed to accommodate a high percentage of driver abilities, and available sight distance translates directly to the safety of a road. As drivers age, some require additional time to make and act on decisions for the driving task. Designs which once provided ample sight distance for perception, identification, judgment and reaction may no longer provide the same factor of safety for older drivers. To make matters worse, designs have changed over time as engineers learned more about drivers, vehicles and the designs themselves, leading to a mix of geometry types for older drivers to contend with. Further, sight distance depends on many variables, including original design and earthwork, curvature, land use and development and horticultural artifacts (tree growth, tall corn on corners, etc.). Researchers at Iowa State are investigating the potential for LIDAR and other advanced mapping technologies to provide an assessment of the State’s highway system with regard to sight distance limitations, particularly as they may impact older drivers. Looking downstream at the remaining left abutment of a washed-out bridge near Sparta, N.J. Caption: Satan's Kingdom Bridge after the Flood - Photo taken by Robert D. Hart, Copyright © 1999 Source: ASHTO Green Book p. P. 741 Iowa DOT Linn/Cedar/Clinton US 30 LIDAR Project This highway improvement project crosses three counties in eastern Iowa. Plans are to upgrade the primarily two lane facility to four lanes and include intersection improvements and town bypasses. Conventionally, aerial photographs would be processed with soft copy photogrammetry to obtain digital elevation models, contour mapping and digital orthophotos to support project planning (location, environmental assessment) and preliminary to final design (earthwork calculations, vertical and horizontal alignment and cross section design, drainage). In this project, the Iowa DOT is obtaining LIDAR-derived 3D products and digital imagery. CTRE is tracking all phases of the project to report on the differences between the use of LIDAR and photogrammetry in order to develop guidance to transportation agencies considering the use of the new technology Application #1: Pavement Performance Model Improvement Current models of pavement performance may include: Age of pavement Present condition Design (pavement type and thickness) Materials (quality/type) Traffic (esp. trucks) Environment Q: Can inclusion of drainage and cross section improve predictive capabilities? A: Iowa has 110,000 miles of road, mostly two lane on county or municipal systems. While the State maintains a comprehensive database of inventory elements on its entire system, and has one of the most complete pavement management systems in the US, data on cross slope and drainage are not included as elements. To date, there has been no cost effective way to measure these features. Consequently, pavement performance models do not generally include cross section detail and drainage as predictor variables. CTRE is testing the ability of LIDAR to provide these inputs, and is evaluating the contributions these new variables can make to improve the predictive capabilities of the models. Performance of substandard cross section Performance of well-engineered cross section Abstract: At Iowa State University, researchers from the Center for Transportation Research and Education (CTRE) and the Department of Civil and Construction Engineering are studying potential applications of remote sensing to transportation. As part of the National Consortium for Remote Sensing in Transportation – Infrastructure (NCRST-I), and USDOT’s Midwest Transportation consortium (MTC), CTRE is conducting several LIDAR assessments. Conceptual cost structures and relative performance assessments are presented for three conventional data collection and processing methods and compared to new technologies (LIDAR and IFSAR or INSAR). New applications include pavement performance prediction related to drainage and runoff, safety implications of geometric design and an aging population, bridge and culvert surety related to local surface hydrology. CTRE is also tracking the progress of the Iowa DOT as it conducts its first, production scale project planning and design study using LIDAR in lieu of photogrammetric techniques. In a related effort, CTRE is conducting comparisons or LIDAR and photogrammetry in best and worst case environmental conditions. Project principal investigators are Dr. Reg Souleyrette and Dr. Shauna Hallmark. Research contributors are David Veneziano, Zachary Hans, Dr. Aemal Khattak and Dr. Omar Smadi. The projects are sponsored by the USDOT RSPA, USDOT Transportation Centers Program, Iowa State University, the University of Nebraska and the Iowa Department of Transportation. The researchers are responsible for the findings which do not necessarily represent policy of the sponsoring agencies. RTK GPS TOTAL STATION - SURVEY LIDAR IFSAR Application #2: Surety of Bridges and Culverts on Secondary Systems Clearly, bridges are a vital component of the Nation’s highway infrastructure. Their importance is well demonstrated by myriad hydrological studies, monitoring systems and improvements allocated billions of dollars in recent years. However, for most of the Nation’s bridges and culverts (those located on secondary and municipal systems) little is known about the potential impact of flood events – the data required are just too extensive and expensive. CTRE is investigating the potential for LIDAR and other advanced mapping technologies to provide terrain data on a large enough scale to begin the development of databases to support study, planning, prioritization and response for flooding of Iowa’s rural bridges and culverts. The graphic depicts the hundreds of stream crossing locations for a single, primarily rural Iowa county Iowa DOT Highway 1 LIDAR/Photogrammetry Comparison As everyone knows, highway projects take years to complete. It seems as soon as the highway is opened, it is congested – and then – they tear up the street again to put in some utilities. Highway planners and engineers often face these sentiments from the public. However the two edged sword strikes again if highway agencies move too quickly through a project, especially if real or perceived environmental and societal impacts are not carefully thought out and effectively presented to the public. Further, some of the information needed to make prudent location decisions takes months if not years to acquire, as traditional data collection techniques (photogrammetry) require long lead times to plan missions and process data. This is exacerbated by requirements for leaf-off and proper sun angle. In this project CTRE is comparing the cost, timeliness, utility, and accuracy of digital imagery and LIDAR collected under worse case (mid summer) conditions to photogrammetric products developed during the same and under optimal conditions. The objective is to provide these comparisons specifically as related to highway location and EIS and to determine if LIDAR can be used under non-optimal conditions to provide quality products to speed up the highway development process. Hoel and Garber: Traffic and Highway Engineering Photogrammetry Travel Lanes Usable Shoulder Rounding of Drainage Channel Travel Lanes Narrow Shoulders Removes Water too Slowly Unsafe Transportation Applications of Advanced Geo-surface Mapping