Udon Ratthaya Expressway

The Udon Ratthaya Expressway (ทางพิเศษอุดรรัถยา), also known as the Bang Pa-in–Pak Kret Expressway (ทางด่วนสายบางปะอิน–ปากเกร็ด), is an expressway in Thailand, located in Nonthaburi, Pathum Thani and Phra Nakhon Si Ayutthaya provinces. The expressway is a controlled-access toll road.

History
Udon Ratthaya Expressway was proposed to handle road traffic for the 13th Asian Games which were held at Thammasat University Rangsit Campus in 1998. It was also aimed at reducing road traffic on Vibhavadi Rangsit and Phahon Yothin roads leading northwards out of Bangkok. The first section between Chaeng Watthana–Chiang Rak was opened on 2 December 1998. It is a continuation of the Si Rat Expressway Section C. The second section between Chiang Rak–Bang Sai was opened on 1 November 1999.

According to an official EXAT annual report, the expressway was used by 25,842,029 cars in the 2022 fiscal year, with an average of 74,688 cars per day.

Route
Kilometre 0 is counted at Chaeng Watthana Interchange.