1.4 Pavement design shall be based on the accumulated number of standard axle loads predicted during the first 7th year after construction high type surface shall be either reinforced concrete pavement or asphaltic concrete pavement intermediate type surfacing shall be double bituminous surface treatment or equivalent.
1.5 Department of Highways or AASHTO recommendations shall be followed for any design details which are not separately specified.
1.6 The designation of a highway class shall be based on the following.
D class following 7th year forecast ADT. or shall be justified base on separate economic feasibility calculations.
Class 1, 2 and 3 highway following 15th year forecast ADT. reaching minimum specified volumes.
Class 4 highways require a 7th year forecast ADT of more than 300 and a 15th year forecast ADT. of less than 1,000. Class 5 highways require a 7th year forecast ADT. of less than 300 and a 15th year forecast ADT. or more than 300.

2. Criteria for Highway Cross Section

2.1 The traffic lane width shall be as stated in the “minimum design standards” except in the case of widening of an urban roadway to more than 2 lanes within a narrow right of ways, in which the additional outer lanes may be narrower than the standard lane width, but not less than 2.50 m. width.
2.2 The width of shoulder shall be as state in “Minimum Design Standards” except for highways designated in certain urban or crowded areas where the shoulder shall be paved, 3.00 m. wide, and pertain to all of the highway classes except for class 5.
2.3 The width of the sidewalk for highways in urban area shall be as stated in the Department’s typical ultimate design cross section for each right of ways width. In the case where the right of ways is narrower than that of the minimum standard right of ways, the width of the sidewalk may be reduced.
In the case where the pedestrians traffic is heavy, and where space is available, the width of the sidewalk may be wider than of the standard, but not more than 5.00 m.
2.4 The typical cross section for rural divided highway with 80 m. or more wide right of ways and for urban with different standards right of ways shall follow the standard drawings of the Bureau of Locations and Design Department of Highways.

3. Criteria for Bridge Cross Section

3.1 The width of bridge is generally as designed standard.
3.2 The roadway width, sidewalk width, barrier width and railing of bridges in urban areas may be                   specially designed to conform to existing conditions.

3.3 The outside edge of bridge roadway, devided highway of special highways, should be sidewalk of 1.50 meter width while the inside edge should be 0.50 meter thick barrier.
3.4 For bridges located on a horizontal curve, the bridge roadway width shall be widened as the width of the approach road. If the width of bridge roadway is more than 0.50 meter. It will be counted as 1.0 meter. Anyhow, the width of bridge roadway should not be less than that as stated in clause 3.1.
3.5 For highways which are to be widened in the future the bridge roadway width shall be set according to the ultimate cross section of the highway or to minimize initial cost, the bridge may be designed for stage construction by widening to meet ultimate design requirements.
3.6 When the bridge is a part of an interchange of an overpass, the width of the bridge shall be set according to the geometrical cross section of the related pavement structure.

Highway Project

Ongoing Outstanding Highway Project   Completed Outstanding Highway Project Highway Project Commencing in Fiscal Year 1999 Highway Project Completed in Fiscal Year 1999

 Ongoing Outstanding Highway Project

Though the financial crisis in Fiscal Year is not over, it is considered that the pressure is much relief. However, Departmet of Highways continues stressing on the expedition of its budget to the maximum benefit of the road users by adjusting the designed standard to cope with current economics circumstances; or in other words Department of Highways tries to pay less for same servicing standard.
            Outstanding projects in this fiscal year is chiefly the projects which have already been commenced in prior years, for instance, the inter-city motorway project and the four-lane divided highway project. And, in order to develop more completed Asean Highway Network, the conference on network designation has been held among the Asean member countries. The network is designated to link communication of the most potential areas of each member country with each other. Therefore the Asean Highway Project will be one of the outstanding projects in the future besides the following outstanding ones:-

Four-Lane Highway Construction Project

          Four Lane Highway Construction Project I

                       Project History

                        The Governmental of Thailand has approved, on February 16,1993, the plan for Four lane Highway Construction Project I in accordance with its policy to improve all main route to each part of the country to four-lane highways for the convenience and safety of all road users. The total distance of the roads to be improved is 1,891 kilometers and the project duration is between the year 1996-1999. The total cost of the project estimated and Baht 45,900 Million and the project is as summarised below.

                        Northern Region Bangkok-Changrai-A. Mae sai including Lampang-Chiangmai, total distance 467 kilometers, estemated construction cost Baht 16,600 Million.

                        North Eastern region Bangkok-Nong Khai, total distance 231 kilometers, estimated construction cost Baht 4,600 Million.

                        Central Region Bangkol-Trad, total distance 120 kilometers, estimated construction cost Baht 3,000 Million.

                        Southern Region Bangkon-Sungaikolok, total distance 893 kilometers estimated construction cost Baht 21,700 Million.

                        Project Implimentation

                        Detailed design for the project has been completed by Department of Highways and after that procurement for contractors and construction phase has been accomplished.

Four-Lane Hihgway constructiion Project II

         Project History

         Upon the cabinet approval of the Four-Lane Highway Construction Project I, the cabinet has a remark that the Ministry of Transport and Communications should carry on the next programme for four-land highway construction. The Ministry, therefore, has assigned Department of Highways to propose to the cabinet the Plan covers the construction of four-lane highways from eastern to western region and from the north to the south has been proposed at the total distance of 4,366 kilometers and the estimated cost of Baht 103,300 million. The Project duration is 11 years during the year 1996 to  2006. The proposed highways are following:-

1.   Nakhon sawan-Phitsanulok-A. Den Chai-Phrae-A. Ngao(include Phrae-Nan), total distance 491 kilometers.

2.      A. Mae Sod- Tak- Sukhothai-Phitsanulok- Khon Khaen-Kalasin-Mukdahan, total distance 773 kilometers.

3.    Saraburi-Petchabun-A.Lom Sak-Loei, total distance 445 kilometers.

4.     B.Hin Kong-Nakhon Nayok-Prachinburi-A.Aranyaprather-Thai/Cambodia Border, total distance 194 kilometers.

5.     Nakhon Pathom-Suphanburi-A.Pa Mok-saraburi(incl.Kanchanaburi-Suphanburi), total distance 228 kilometers.

6.     Nakhon Sawan-Chaiyaphum-A.Ban chai-Mahasarakham-Roi-et-Yasothon-Ubonratchathani-Chong Mek, total distance 672 kilometers.

7.      A.Sattahip-A.Phanomsarakham A.Kabinburi-A.Pak Thongchai- A.Choke Chai-A.Nang Rong-A.Parsart-Ubonratchathani-Mukdahan(incl.A.SiKhiu-A.Chok Chai),total distance 834 kilometers.

8.      Surat Thani-Nakhon Si Thammarat-Song Khla-Hat Yai (include. Song Khla – A.Chana), total distance 370 kilometers.

9.     Phuket-Phang Nga –Krabi-Phattalung (include, Huai Yot-Nakhon Si Thammarat), total distance 389 kilometer.

Later, on January 10,1995, the cabinet has approved the said plan in priciple and also commented that more roads should be included and the feacibility study be carried out for more details;moreover implementation schedule and financial management should be proposed to the cabinet further.

Department of Highways then engaged a consultant to proceed with such comment and the following two more networks had been included:-

Network I, Loei-Udon Thani-Sakon Nakhon-Nakhon Phanom at the total distance of 333 kilometers.

Network II, additional six roads, i.e. A.Sak Lek-A. Wang Thong, Sukhothai-] sSawankhalok,Sikhio-Chaiyaphum,A.Kaeng Khro-Chum Phae, Chumphon-Ranong and Surat Thani-Phangnga at the total distance of 138 kilometers

The study has already been completed and is now on the process of proposing for cabinet consideratioon together with Four Lane Highway Construction Plan(Phase 2) which will be implemented during the 9^th National Economic and Social Development Plan (2000-2008).

However for some high priority routes running close to main town of being main route of Thailand, request for budget allocation has been made and proceeded.

           Project Implimentation

Department of Highways has proceeded with this project, from the feasibility study to survey and detailed engineering design, preparation of construction and finally for conxtruction , as shown on the summary below: