Originally Posted by
eriond
I need to get from South Sathorn Road to BKK airport on a Monday at 3pm on a Monday (not in a rush). According to Google Maps, it appears that the distance is ~36km.
The fare for 36km should be THB229, plus whatever time spent in traffic jams (THB1.5/min @<6km/h), plus highway tolls (>=THB70 depending on which on-ramp is chosen) if any.
Not sure about traffic conditions at 3pm (upper Sukhumvit might be a bottleneck, more so than the slightly longer route via Phetchaburi Rd.), but surface streets are certainly more affected by heavy downpours than the elevated highway, should you be making the trip in the coming month or two.