The "Stormwater Management and Road Tunnel" or "SMART Tunnel", 
is a storm drainage and road structure in Kuala Lumpur, Malaysia, a major national project in the country. The 9.7 km (6.0 miles) tunnel is the longest stormwater tunnel in South East Asia and second longest in Asia.
The main objective of this tunnel is to solve the problem of flash floods in Kuala Lumpur and also to reduce traffic jams along Jalan Sungai Besi and Lok Yew flyover at Pudu during rush hour. There are two components of this tunnel, the stormwater tunnel and motorway tunnel. It is the longest multi-purpose tunnel in the world.
It begins at Kampung Berembang lake near Klang River at Ampang and ends at Taman Desa lake near Kerayong River at Salak South. The project is led by the government, including Malaysian Highway Authority (LLM) and the Department of Irrigation and Drainage Malaysia (Jabatan Pengairan dan Saliran = JPS) and also a company joint venture pact between Gamuda Berhad and Malaysian Mining Corporation Berhad (MMC).
Route background
The Kilometre Zero of the tunnel starts at Salak Interchange.
History
Construction of the tunnel began in 25 November 2003. Two Herrenknecht's Tunnel Boring Machines (TBM) from Germany were used, including "Tuah" on north side and "Gemilang" on south side.
On 11 December 2003, the 13.2 m diameter Mixshield TBM, Tuah, completed a 737 m section after 24 weeks of excavation. By the end of January 2004, Tuah would start a second drive covering a distance of 4.5 km to Kampung Berembang lake. A second TBM, Gemilang, has bored 350 m since getting underway in August 2004. Operated by Wayss & Freytag of Germany, this second Herrenknecht's TBM would drive 5.3 km in the south of the city to Taman Desa lake.
On 22 April 2006, the Gemilang's TBM completed digging on the south side at the Taman Desa outfall, while the Tuah's TBM completed digging in the Kampung Berembang area in 2 April 2007.
The motorway sections on the SMART system was officially opened at 3:00PM, 14 May 2007, after multiple delays.
Meanwhile, the stormwater sections on the SMART system began operations at the end of June 2007.
How SMART Tunnel works
First mode (Normal conditions)
The first mode, under normal conditions where there is no storm, no flood water will be diverted into the system.
Second mode (Most storms)
When the second mode is activated, flood water is diverted into the bypass tunnel in the lower channel of the motorway tunnel. The motorway section is still open to traffic at this stage.
Third mode (Major storms)
When this mode is in operation, the motorway will be closed to all traffic. After making sure all vehicles have exited the motorway, automated water-tight gates will be opened to allow flood waters to pass through. The motorway will be reopened to traffic within 48 hours of closure.
Tunnel safety
Ventilation or escape shafts at 1 km intervals provide ventilation within the motorway. To protect the ventilation system during floods, the system consist of a series of shafts; each containing an exhaust and fresh air injector. This design enables fans situated outside the SMART Tunnel to create a longitudinal flow in the tunnel between the shafts that permits the air in the tunnel to be continuously renewed and to enable extraction of exhaust fumes. The feature also allows smoke control in the event of a fire. The SMART Tunnel is also equipped with fire-fighting, telecommunication and surveillance equipments at 1 km intervals.
Technical specifications
The north bound entrance of SMART Tunnel on the Kuala Lumpur-Seremban Expressway.
Stormwater tunnel
- Construction cost: RM1,887 million (US$514.6 million)
- Stormwater tunnel length: 9.7 km (6.0 mi)
- Diameter: 13.2 m (43.3 ft) (outer diameter)
- Tunnelling method: Tunnel Boring Machine (TBM)
- TBM type: Slurry shield
Motorway tunnel
- Motorway tunnel length: 4 km (2.5 mi)
- Structure type: Double Deck
- Ingress and egress: 1.5 km (0.93 mi) at Jalan Sultan Ismail and Jalan Imbi
- Length: 1.4 km (0.87 mi) at Jalan Tun Razak
- Links: 1.6 km (1 mi) at Kuala Lumpur-Seremban Expressway Links: City Centre near Kg. Pandan Roundabout KL-Seremban Expressway near Sungai Besi Airport
Features
- Longest tunnel in Malaysia.
- 9.7 km (6.03 miles) stormwater by-pass tunnel.
- 4 km (2.49 miles) double-deck motorway within stormwater tunnel.
- The motorway tunnel is suitable for light vehicles only. Motorcycles and heavy vehicles are not allowed.
- Ingress and egress connections to the motorway tunnel linking the southern gateway to the city centre.
- Holding basin complete with diversion and tunnel intake structures.
- Storage reservoir and a twin-box culvert to release flood discharge.
- State-of-the-art operations control room equipped with the latest systems in operations management, surveillance and maintenance of the SMART system.
- Custom-made fire engine units consisting two modified Toyota Hilux, parked at two different locations for quick access to the tunnel in case of fire at both carriageways.
Toll rates
| Class | Type of vehicles | Rate (in Malaysian ringgit (RM)) | Notes |
| 1 | Private car | RM 2.00 | TnG and TAG are also available at this toll plaza. |
| 4 | Taxis | RM 2.00 | Toll charges are paid by passengers only. |
FM Radio channels available in the tunnel
List of interchanges
From/To 
East-West Link Expressway
| km | Exit | Interchange | To | Remarks |
0 |
|
| EAST-WEST LINK EXPRESSWAY
SOUTHEAST
Cheras
NORTHWEST
Petaling Jaya
Shah Alam | Direction Y junctions |
 AH 2 KUALA LUMPUR-SEREMBAN EXPRESSWAY
MetaCorp border limit |
 SMART TUNNEL
SMART border limit |
|
| P SMART Tunnel operation office |   TnG TAG i
Customer Service Centre
SMART Tunnel operation office | South bound on Cheras, Petaling Jaya and Shah Alam stretches only |
SMART toll plaza
SMART
RM (Cash) TnG TAG TAG TnG RM (Cash)
Open toll system
Pay toll |
MOTORWAY TUNNEL
Dry sections
Start/End of tunnel
Maximum height 2 m
Speed limit 60 km/h |
|
|
|
| From/To Motorway tunnel |
From/To Kuala Lumpur-Seremban Expressway
Motorway tunnel
Sultan Ismail link tunnel
| km | Exit | Interchange | To | Remarks |
| EXIT 3802 | Sultan Ismail link tunnel
Dry sections
Tunnel entry south bound | MOTORWAY TUNNEL
Cheras
Petaling Jaya
AH 2Kompleks Sukan Negara
 Kuala Lumpur International Airport (KLIA)
 AH 2Seremban
AH 2Melaka
AH 2Johor Bahru | Tunnel interchange
Upper floor |
MOTORWAY TUNNEL
Dry sections
Start/End of tunnel
Maximum height 2 m
Speed limit 60 km/h |
SMART TUNNEL
Start/End of expressway
SMART border limit |
JALAN DAVIS
DBKL border limit |
|
|
| NORTHWEST
SULTAN ISMAIL-KAMPUNG PANDAN LINK (JALAN DAVIS)
KUALA LUMPUR INNER RING ROAD
Jalan Imbi
Jalan Sultan Ismail
Jalan Bukit Bintang |
|
Tunnel in popular culture
Genting Klang-Pahang Highway
