Table 6.

Identified factors, theme 5: alternative transport modes

Theme	Factor	References	Expected impact towards a Direct Connection
Alternative transport modes	Colonial ties	Hwang and Shiao (2011)	+
	Common border	Gong et al. (2018)	−
	Common language	Gong et al. (2018)	+
	Logistics performance	Li et al. (2020), Walcott and Fan (2017)	+
	Distancea	Gong et al. (2018)	−
	Infrastructureb	Chu (2014), Islam et al. (2013)	+
	Security issues	Islam et al. (2013)	−
	Trade agreement	Hwang and Shiao (2011), Walcott and Fan (2017)	+
	Trade facilitation	Chu (2014), Gong et al. (2018), Hwang and Shiao (2011), Walcott and Fan (2017)	+
	Trade flow	Gong et al. (2018), Hwang and Shiao (2011), Kreutzberger and Konings (2016)	+
	Transit time	Andersen and Christiansen (2009), Boonekamp and Burghouwt (2017), Islam et al. (2013), Jeong et al. (2007), Li et al. (2020)	−
	Voyage cost	Islam et al. (2013)	−

^aIn Theme 5, Distance refers to the “Great Circle Distance”, while the corresponding factor within the maritime context (Themes 1, 2, 3 and 4) is the Nautical Distance

^bIn Theme 5, Infrastructure refers to the quality and condition of the track (rail freight) or the existence of state-of-the-art cargo handling equipment (air freight), while the corresponding factor within the maritime context (Themes 1, 2, 3 and 4) is the Port Infrastructure.