OpenStreetMap

Yup. Most parts east of Clementi Road should be merged as there is no physical road divider

hmm, should small sections of curbs be mapped/accounted for, like in https://www.google.com/maps/@1.2887926,103.778022,3a,15y,298.12h,83.66t/data=!3m7!1e1!3m5!1s09yPUEAt6NhWfLSNkBNXcw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D6.344078674918336%26panoid%3D09yPUEAt6NhWfLSNkBNXcw%26yaw%3D298.1208654099016!7i16384!8i8192!5m1!1e4?entry=ttu&g_ep=EgoyMDI0MTEyNC4xIKXMDSoASAFQAw%3D%3D? (just for reference, ik we can't use gmaps as source)