[3] Work on the first phase of the CTE, between Ang Mo Kio Avenue 1 and Thomson Road, commenced in July 1981.

[4] Intended to alleviate heavy traffic along Upper Thomson Road, a 3 kilometres (1.9 miles) segment of the expressway between Ang Mo Kio Avenue 1 and Jalan Toa Payoh opened in March 1983,[5] while the segment of expressway between Jalan Toa Payoh and Thomson Road was opened on 18 May 1985 by MP for Moulmein Lawrence Sia.

[6] In August 1985, construction commenced on a 3 kilometres (1.9 miles), S$18 million segment of the expressway in Ang Mo Kio.

[7] This segment of expressway was opened to traffic in January 1987,[8] while the 1.7 kilometres (1.1 miles) section between Ang Mo Kio Avenue 5 and Yio Chu Kang Road was constructed between August 1986[9] and November 1988.

[21] In 2008, a large-scale improvement of the CTE was initiated, and the first phase of the scheme, consisting of the expansion of the expressway between Ang Mo Kio Avenues 1 and 3, started in June 2008, and cost S$17 million.