The Central Expressway (CTE) links the city to districts in the north of Singapore such as Toa Payoh, Bishan and Ang Mo Kio.1 To its north is the Seletar Expressway and to its south, the Ayer Rajah Expressway.2 Opened in 1991, parts of the CTE are underground, forming the first underground highways of Singapore.3
The 15.5-kilometre-long CTE4 was constructed at a cost of S$500 million. It was built in two phases with different stages that involved a total of eleven parts or sections of construction.5 The laying of the 12.5-kilometre stretch from Yio Chu Kang Road to Bukit Timah Road formed Phase 1 of the construction, which was completed in the late 1980s.6 The portion of expressway between Yio Chu Kang and Ang Mo Kio Avenue 5 was officially opened on 17 June 1989 by then member of Parliament for Cheng San Group Representation Constituency, Heng Chiang Meng. The construction of this 1.7-kilometre three-lane carriageway was delayed by almost two years due to resettlement issues when residents in the area had to be relocated. The first phase of the expressway construction also included the building of the Whampoa Flyover connecting the Pan-Island Expressway (PIE) and CTE.7
In April 1986, the Public Works Department (PWD) began accepting tenders for Phase 2 of the construction, which involved 3.7 km of the CTE within the city area.8 PWD engineers took more than two years to finalise the plan for this phase before requesting for tenders. At the time, it was not only touted as the single most expensive road project undertaken in Singapore because of the construction of two underground tunnel ways, but also considered a complicated and difficult road to lay because of its design. From more than 10 civil engineering firms that prequalified for the job and eight shortlisted candidates, contracts for the construction of various jobs in this phase were awarded to a group comprising four firms: Bocotra Construction, Lee Kim Tah, Metrobilt and Wang Coo-Kien. Construction of the road commenced on 25 January 1988 and excavation work for the underground tunnels began in July that year.9 The government acquired nearly 54,000 sq m of land in Orchard Road, Cavenagh Road and Clemenceau Avenue for the project, after first earmarking the areas for the expressway project in 1986. The total cost of the Phase 2 of the construction was approximately S$350 million.10
As a part of the PIE widening project in 1990, the Whampoa Flyover was improved to become the only four-way junction for intersecting expressways in Singapore. The flyover was officially reopened on 29 October 1994 by then Acting Minister for National Development Lim Hng Kiang.11
Of the total 3.7 km of CTE from Bukit Timah Road to Chin Swee Road, only about 1.3 km of the expressway form the surface roads, including parts that were constructed below existing road levels. The rest of the expressway is underground.12 There are two tunnels: north and south. The north tunnel is a 41-metre-wide, 700-metre-long stretch of road from the junction of Bukit Timah and Cavenagh roads to the junction of Clemenceau Avenue and Cairnhill Circle. This portion of the expressway is divided into northern and southern carriageways with four lanes each.13 An interchange was built at Clemenceau Avenue to give motorists access to Orchard Road via the CTE. Due to the existence of the interchange, both Cairnhill Circle and Bideford Road were converted into one-way lanes when the CTE was completed.14
The south tunnel extends from Kramat Road to Chin Swee Road. Measuring a total of 1.7 km, it passes below Penang Road, the Singapore River and Havelock Road. It has three lanes on its either side.15 The portion of the tunnel underwater is near Clemenceau Bridge over the Singapore River.16 This section of the expressway took almost two years to build as the river had to be dammed in stages during the construction. The construction of the south tunnel was considered the toughest part of the entire CTE project because of its complex layout. A portion of the expressway even cuts across a Mass Rapid Transit (MRT) tunnel between Somerset and Dhoby Ghaut MRT stations. It also cuts across Stamford Canal near Kramat Lane. A three-storey interchange with five slip tunnels links the expressway with some of the surface roads such as Merchant Road, Havelock Road and Upper Cross Street.17
Because of a variety of soils along the route, more than six different types of temporary retaining walls were put up during the excavation and tunnelling work.18 As the diameter of the CTE tunnels is about three to four times that of MRT tunnels, their large size required the use of the cut-and-cover method for most of their construction, instead of the boring method employed in the building of MRT tunnels. Traffic was diverted along the excavation sites, resulting in the loss of two to three lanes along major traffic routes. Instruments were attached to around 40 buildings that came within 50 m of the excavation sites to monitor noise and vibration levels. Some of these buildings included Le Meridien Hotel (later renamed Concorde Hotel), Landmark Tower, Thong Chai Building, Central Building, Liang Court, Singapore Shopping Centre and Haw Par Glass Tower.19 Around 440,000 cu m, or 70,300 truckloads, of concrete was used for the second phase of the construction.20
The final section of the CTE was completed in April 1991. A mass walk-and-jog event was held on 15 September 1991 for people to familiarise themselves with the tunnels a week before the official opening of the CTE. The event saw more than 10,000 participants on the seven-kilometre route which covered the tunnels and their surface connections. The event was flagged off by then Senior Parliamentary Secretary for National Development Lee Yiok Seng.21 The official opening ceremony of Phase 2 of the CTE project took place on 21 September 1991. The tunnels were opened to traffic at 6 pm that day and about 50 vintage cars led the procession with Senior Minister of State for Education Tay Eng Soon at its head in a 1935 BMW. They became the first motorists to use this portion of the CTE.22
Detectors installed in the tunnels warn of congestion should lanes close for reasons such as a traffic accident. Ventilation and lighting are automatically adjusted according to the volume of the traffic in the tunnel and brightness outside respectively.23 Staircases leading to the ground level can be found every 200 m. Closed-circuit television cameras are installed every 100 m while hydrants, hose reels and fire extinguishers are located every 50 m. The tunnel is monitored via the computerised 24-hour tunnel control centre.24
Along the CTE are situated both private as well as Housing and Development Board residential developments. Landmarks include the ITE (Institute of Technical Education) College Central, Da Qiao Primary School, Singapore Cheshire Home, Serangoon Gardens Estate, Ang Mo Kio Industrial Parks 1 and 2, Construction Industry Training Institute, Toa Payoh Industrial Park, Volkswagen Golf Centre, St Andrew’s Secondary School, St Wilfrid Field, Bendemeer Secondary School and the Seventh Day Adventist Church. The CTE also runs below a number of landmarks in the Central Business District, such as the Istana Park. Vehicular bridges were constructed over the Kallang River and Sungei Whampoa.25
Naidu Ratnala Thulaja
1. Land Transport Authority. (2013, August 27). Central Expressway (CTE). Retrieved 2016, July 28 from Land Transport Authority website: https://www.lta.gov.sg/content/ltaweb/en/roads-and-motoring/projects/central-expressway-cte.html
2. Singapore Land Authority. (n.d.). OneMap. Retrieved 2016, July 28 from OneMap website: https://www.onemap.sg/index.html
3. CTE project completed. (1991, May 11). The Straits Times, p. 22. Retrieved from NewspaperSG.
4. Land Transport Authority. (2013, August 27). Central Expressway (CTE). Retrieved 2016, July 28 from Land Transport Authority website: https://www.lta.gov.sg/content/ltaweb/en/roads-and-motoring/projects/central-expressway-cte.html
5. Lee, H. S. (1988, March 2). Work starts soon on underground highway. The Business Times, p. 18. Retrieved from NewspaperSG.
6. Chin, A. (1987, March 4) CTE bids rejected, fresh tenders called. The Straits Times, p. 15. Retrieved from NewspaperSG.
7. CTE stretch at Ang Mo Kio now open. (1989, June 18). The Straits Times, p. 16. Retrieved from NewspaperSG.
8. Lee, H. S. (1988, March 2). Work starts soon on underground highway. The Business Times, p. 18. Retrieved from NewspaperSG.
9. Yap, M. (1986, April 18). Tenders open for phase two of CTE. The Straits Times, p. 16; Work on CTE tunnel roads begins. (1988, July 18). The Business Times, p. 20. Retrieved from NewspaperSG.
10. Singapore. Parliament. Official reports – Parliamentary debates (Hansard). (1988, March 17). Main and development estimates of Singapore for the financial year 1st April, 1988 to 31st March, 1989 (Vol. 50, col. 905). Retrieved from Parliament of Singapore website: https://sprs.parl.gov.sg/search/topic.jsp?currentTopicID=00060949-ZZ¤tPubID=00069554-ZZ&topicKey=00069554-ZZ.00060949-ZZ_1%2Bid008_19880317_S0002_T00021-budget%2B; Yap, M. (1986, April 18). Tenders open for phase two of CTE. The Straits Times, p. 16; Kumar, S. (1991, January 4). CTE tunnels ready before year’s end. The Business Times, p. 24. Retrieved from NewspaperSG.
11. Road tunnel project to cost $1 b more. (1994, October 30). The Straits Times, p. 1. Retrieved from NewspaperSG.
12. Lee, H. S. (1988, March 2). Work starts soon on underground highway. The Business Times, p. 18. Retrieved from NewspaperSG.
13. Kumar, S. (1991, January 4). CTE tunnels ready before year’s end. The Business Times, p. 24. Retrieved from NewspaperSG.
14. Lee, H. S. (1988, March 2). Work starts soon on underground highway. The Business Times, p. 18. Retrieved from NewspaperSG.
15. Toh, T.L. (1990, February 19). CTE work diverts S’pore River. The New Paper, p. 4. Retrieved from NewspaperSG.
16. Dhaliwal, R. (1990, November 3). Water floods part of CTE underground tunnels, The Straits Times, p. 21. Retrieved from NewspaperSG.
17. It includes first underground road tunnels in S’pore. (1991, May 11). The Straits Times, p. 22. Retrieved from NewspaperSG.
18. Kumar, S. (1991, January 4). CTE tunnels ready before year’s end. The Business Times, p. 24. Retrieved from NewspaperSG.
19. Lee, H. S. (1988, March 2). Work starts soon on underground highway. The Business Times, p. 18. Retrieved from NewspaperSG.
20. CTE project uses 5,000 truckloads of concrete each month. (1989, December 16). The Straits Times, p. 24. Retrieved from NewspaperSG.
21. 10,000 throng CTE tunnel for jog and walk. (1991, September 16). The Straits Times, p. 1. Retrieved from NewspaperSG.
22. Vintage cars in drive for funds to be first to use tunnels. (1991, September 20). The Straits Times, p. 26. Retrieved from NewspaperSG.
23. Work begins to put finishing touches to some parts of CTE. (1990, June 2). The Straits Times, p. 22. Retrieved from NewspaperSG.
24. High-tech systems to ensure tunnels function round the clock. (1988, March 2). The Straits Times, p. 15. Retrieved from NewspaperSG.
25. Singapore Land Authority. (n.d.). OneMap. Retrieved 2016, July 28 from OneMap website: https://www.onemap.sg/index.html
The information in this article is valid as at 2016 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic.