Labor costs required to collect and prepare highway inventory datasets can range from $72 to $1,075 per mile.

A review of highway inventory data collection methods vital to the implementation of the Highway Safety Manual (HSM) at the state level.

Made Public Date
08/14/2018
Identifier
2018-SC00405
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Summary Information

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 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 (Light Detection and Ranging) systems traveling at highway speeds.

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.

Overall, GPS data logger and robotic total station can gather all required feature data, but they impose longer field data collection times and expose data collection crews to dangerous road traffic. Photo/video logging and aerial imagery, when used together, can collect nearly all required feature data, except roadside slope. The mobile LiDAR has the capability to collect all required feature data in a short amount of field time, but the data require extensive reduction efforts.

The table below provides a cost comparison between different highway inventory data collection methods.
 

Highway Infrastructure Data Collection
GPS Enabled
Photo/Video
Log
Satellite/ Aerial Imagery
Mobile LiDAR
GPS Data Logger
Robotic
Total
Station
Type of Segment Selected
1,2,3,4
1,2,3,4
1,2,3,4
2,3,4
1,3,4
Capability of Collecting HSM-related Roadside Features
Some
Some
All
All
All
Total Length (mi)
28.0
7.0
14.2
1.3
1.3
Total Data Collection Time (man-hr)
4.0
- -
8.0
6.0
13.0
Total Data Reduction Time (man-hr)
23.0
10.0
70.0
3.5
3.5
Total Time (man-hr/mi)
0.96
1.43
5.50
7.31
12.70
Total Cost ($/mi)
$72
$107
$915
$700
$1,075

(Note: 1=rural multi-lane highway; 2=freeway segment; 3=rural two-lane highway; 4=urban/suburban arterials)