Central Expressway, Singapore

thumb|A long exposure of the CTE near Exit 7B (Jalan Bahagia).

The Central Expressway (CTE) is a major expressway in Singapore connecting the city centre with northern residential towns including Toa Payoh, Bishan and Ang Mo Kio, before linking to the Seletar Expressway (SLE) and Tampines Expressway (TPE). The expressway then turns north, intersecting the Pan Island Expressway (PIE) and passing through Toa Payoh, Bishan and Ang Mo Kio before terminating at an interchange with the Seletar Expressway (SLE) and Tampines Expressway (TPE), and measures . Intended to alleviate heavy traffic along Upper Thomson Road, a segment of the expressway between Ang Mo Kio Avenue 1 and Jalan Toa Payoh opened in March 1983, while the segment of expressway between Jalan Toa Payoh and Thomson Road was opened on 18 May 1985 by MP for Moulmein Lawrence Sia. In August 1985, construction commenced on a , S$18 million segment of the expressway in Ang Mo Kio. This segment of expressway was opened to traffic in January 1987, while the section between Ang Mo Kio Avenue 5 and Yio Chu Kang Road was constructed between August 1986 and

November 1988. and involved the acquisition of land along Orchard Road and Clemenceau Avenue worth over S$20 million. Work on the second phase commenced in June 1987, and the tunnels were constructed using the cut-and-cover method. As the areas along the expressway's route were heavily built-up, precautions were taken to limit disruption to the public during construction, with the exclusive use of hydraulic piling machines and work near residential areas being paused at night. In addition, cofferdams were built in the Singapore River to facilitate construction of the expressway tunnels, and to prevent erosion, the river bed directly above the tunnels was covered with rocks. but the construction of the tunnels was delayed, which the government attributed to a shortage of workers and "poor soil conditions near Cairnhill Circle". Construction on the CTE's second phase was completed in May 1991, and the opening of the two tunnels, which were named the Kampong Java and Chin Swee Tunnels, in September 1991 marked the completion of the expressway.

Impact and expansion

Traffic volumes along the CTE rose after the expressway was fully opened, and in May 1994, the section of expressway between Ang Mo Kio Avenue 1 and the PIE was expanded to eight lanes to ease traffic congestion. A traffic monitoring system, the Expressway Monitoring and Advisory System, was introduced on the expressway in March 1998.

By the late 1990s, the CTE faced traffic congestion issues, and while a road pricing scheme was introduced to rectify the issue, it was unable to eliminate it.

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. Subsequently, flyovers were constructed at the junction with the PIE to improve traffic flow, while other sections of the CTE, between Bukit Timah Road and Yio Chu Kang Road, were widened, and the improvement scheme was completed by December 2011.

thumb|right|250px|Central Expressway near the Cavenagh Road exit in December 2005.

List of interchanges and exits