Bangkok Expressway and Metro (BEM) has installed tap-and-scan points on the Si Rat-Outer Ring Road Expressway and the Udon Ratthaya Expressway (Bang Pa-in-Pak Kret).
Contactless payment can be made with a Visa debit or credit card (PayWave enabled) or a Mastercard (Paypass enabled) from Friday onwards.
The procedure is simple and convenient: stop at the booth, lower the window and touch the card to WiFi-like symbol on the payment device.