Table 1 Existing roadway inventory data collection methods and related studies

Field inventory

Using GPS survey and conventional optical equipment to collect desired information in the field

(Jones 2004; Khattak et al. 2000; Zhou et al. 2013)

Photo/Video log

Driving a vehicle along the roadway while automatically recording photos/videos, which can be examined later to extract information

(Ai and Tsai 2014; Ai and Tsai 2011; DeGray and Hancock 2002; X. Hu et al. 2004; Jeyapalan 2004; Jeyapalan and Jaselskis 2002; Maerz and McKenna 1999; Robyak and Orvets 2004; Tsai et al. 2009; K. C. Wang et al. 2010; Wu and Tsai 2006)

Integrated GPS/GIS mapping systems

Using an integrated GPS/GIS field data logger to record and store inventory information

(Caddell et al. 2009; Jones 2004)

Aerial/Satellite photography

Analyzing high resolution images taken from aircraft or satellites to identify and extract highway inventory information

(Veneziano et al. 2002)