Pan Island Expressway

The PIE was initially conceived by the Public Works Department as part of plans to expand Singapore's road network in the 1960s to cope with a predicted large rise in traffic volume over the next two decades.[7] It was the result of a four-year planning study conducted in 1967 by the Singaporean government and foreign planning consultants. The study was funded by the United Nations Development Programme.[8]

Intended to connect Singapore's satellite towns and industrial estates, it would act as the main connector between the parts of Singapore and would handle high traffic volumes.[9]

Construction of the PIE started in 1964 and took place in four phases.[10] Jalan Toa Payoh, a 2-mile (3.2 km) long segment of the expressway between Thomson Road and Woodsville Circus, was completed in June 1969[9] and the segment between Woodsville Circus and Jalan Eunos, named Jalan Kolam Ayer and Paya Lebar Way, was completed by 1970.[11] Work on the 8-mile (13 km) long section between Jalan Anak Bukit and Thomson Road began in March 1970.[12] During the construction of this section of the expressway, rocks had to be excavated near Adam Road.[13] Also, Kampong Chantek Bahru, off of Bukit Timah Road, was cleared to make way for the expressway.[14]

In January 1975, the section of the expressway between Jalan Eunos and Kallang Bahru was completed, and Jalan Kolam Bahru, between Kallang Bahru and Woodsville Circus, was improved to form a part of the expressway.[15] The section between Adam Road and Jalan Anak Bukit was opened in October 1976[16] and construction of the eastern part of the PIE, between Jalan Eunos and Changi Airport, started in 1976.[17]

Work was started in November 1977 to expand Whitley Road to six lanes, along with the construction of a grade-separated interchange to link it with the PIE.[18] The section of the expressway between Adam Road and Whitley Road was completed by 1978 and was opened to traffic in 1979. Construction from Jalan Anak Bukit to Boon Lay Road was started in 1978.[19] To connect this section to the rest of the PIE, a $15.2 million viaduct over Jalan Anak Bukit and Upper Bukit Timah Road was built.[11]

On 10 January 1981, the 10-kilometre (6.2 mi) segment of the PIE between Jalan Eunos and the East Coast Parkway was officially opened by Teh Cheang Wan, the then Minister of National Development, having cost $50 million to construct.[20] The section of the expressway between Upper Bukit Timah and Corporation Road was opened soon after on 31 January 1981 by Lee Yiok Seng, the Parliamentary Secretary of National Development at the time.[21] With the completion of two flyovers across Aljunied Road and Paya Lebar Road in June 1982—three months ahead of schedule—the PIE was fully opened.[22]

Upon its opening, the Pan Island Expressway had a positive impact on traffic flow in certain areas by alleviating traffic, as was reported by a preliminary Public Works Department study in October 1981.[23] From 1983 to 1984, two lanes, one in each direction, were added to the 16.4-kilometre (10.2 mi) section of the expressway between Mount Pleasant Road and Jalan Boon Lay.[24]

By the early 1990s, the expressway was handling considerable traffic but experienced traffic congestion during peak hours. To alleviate this, portions of the PIE, such as the Woodsville interchange and the intersection with the Central Expressway, were upgraded in May 1991 at a cost of $180 million.[25] In addition, service roads were constructed along the expressway near Toa Payoh and at the Woodsville interchange.[26]

Work began on an 8-kilometre (5.0 mi) extension of the expressway from Hong Kah Circle to Tuas in October 1991, with a northward realignment and extension of the expressway from Hong Kah Circle to Pioneer Road North. Intended to serve as a connection to the Jurong industrial estate and Jurong West, the extension cost $81.3 million[27] and was opened in December 1993.[28]

As the amount of traffic using the KJE and PIE to the Jurong industrial estate increased, the Land Transport Authority upgraded the stretch of the PIE between Tengah Flyover and Tuas Road to a four-lane dual carriageway from the previous three lanes. The work started in March 2004 and was finished in March 2006.[29]

Plans to connect the PIE together with Bedok North Avenue 3 were planned since September 2005, with construction began in May 2006 and completed on 29 November 2008, which provides a direct connection from Bedok to the PIE, after complaints over many years.

Beginning in July 2011, the stretch of the PIE between Clementi Avenue 6 and Adam Road was widened; one lane was added to both sides of the expressway. As well, the Eng Neo, Chantek and Anak Bukit Flyovers were structurally expanded. The widened portions were progressively opened to traffic from July 2013.[30]

During July of 2019, famous Exit 26A (Dunearn & Clementi Rd), Tuas to Changi Airport, known for its exit being on the right instead of being on the common left, began construction for relocation of the exit to be on the left as many faced confusion and missing their exit. On May 2023, the new relocated exit on the left opened. In the process of relocation construction, there were no diversions or delay of traffic.