Johor–Singapore Causeway
The status of the route alignment of the Asian Highway 2 crossing the Malaysia–Singapore border is in dispute. Malaysia had commissioned the Second Link Expressway E3 as part of AH2 to maintain the primary access-controlled highway status of the route. Meanwhile, Singapore had commissioned the Johor–Singapore Causeway and the Bukit Timah Expressway as part of AH2, as the Johor–Singapore Causeway is the main gateway to Singapore from Malaysia, which could mean that the Skudai Highway would be included in the route alignment instead of the Second Link Expressway.