Calculation of the Roadside Clear Zone Width along Highways Based on the Safe Slope

Table 1

Statistical results.

Method	Output	Researchers (publication year)	Research topic
Accident statistics	19	Ogden (1996); Ayati (2007); Sax (2010); Jurewicz (2010); MDOT (2011); Albuquerque (2011)	RCZ width
		Zeeger (1987); Zeeger (1992); Roque (2015)	Roadside slope
		Donnell (2006); Liu (2009, 2011); Doecke (2011); Johnson (2015); Roque (2018); Park (2016); Li (2018, 2019); Yu (2019)	Roadside barrier
Graphical method	7	Turner (1989); AASHTO (1996, 2002, 2006, 2011); MTPRC (2015)	RCZ width
		AASHTO (1996, 2002, 2006, 2011); MTPRC (2015)	Roadside slope
		Ayati (2007)	Roadside barrier
Driving simulation	2	Fitzpatrick (2014, 2016)	RCZ width
Formula derivation	1	Fan (2013)	RCZ width