Knowledge Resources

The purpose of this study was to identify cost-effective methods for collecting and processing highway infrastructure geo-referencing and geo-spatial data. The following data collection methods were compared using field trials on four types of representative roadway segments to assess the utility of each method with respect to enabling agencies to implement the Highway Safety Manual (HSM) and estimate potential crash frequency on local infrastructure.

GPS Data Logger - Integrated GPS/GIS field data logger is manually positioned to record and store inventory information.

Robotic Total Station - An electronic distance measuring system efficiently surveys the position and shape of infrastructure objects.

GPS Enabled Photo/Video Logging – Instrumented vehicles automatically record photo/video data that can be examined later to extract information.

Satellite/Aerial Imagery – High resolution images are taken from aircraft or satellite to identify and extract highway inventory information.

Mobile LiDAR - Instrumented vehicles collect 3-D precision point information using LiDAR systems traveling at highway speeds.

Eleven criteria were utilized to assess performance. Each criterion was assigned a score of 1 to 5 (5 being the best and 1 the worst) to indicate the relative performance of one method compared to the others. The results of the analysis excerpted from the source report are shown below.

	Criteria	GPS Data Logger	Robotic Total Station	GPS Enabled Photo/Video Log	Satellite/ Aerial Imagery	Mobile LiDAR	Weighting Factor
Field Data Collection	Equipment Cost	3	2	4	5	1	0.25
	Labor Cost	2	1	4	5	3	0.25
	Data Collection Time	2	1	4	5	3	0.25
	Safety	2	1	4	5	3	1.00
	Data Completeness	3	4	2	1	5	2.00
	Data Quality	3	4	2	1	5	2.00
	Disruption to Traffic	2	1	4	5	3	1.00
Field Data Reduction	Software Cost	5	4	3	2	1	0.25
	Labor Cost	5	3	4	2	1	0.25
	Data Reduction Time	5	3	4	2	1	0.50
	Data Storage Size	5	4	2	3	1	0.25
Total Weighted Score		24	23	23	21	29