SECTION 304 - SUBBASE COURSE
304-1 Description.
304-1.01 General. The work consists of furnishing, placing and compacting a subbase course of the
specified type in conformity with the lines, grades, thicknesses and typical sections shown in the contract documents.
304-1.02 Optional Type. When the Optional Type subbase item is specified, select any of the four (4)
options as follows:
A.Option A. Subbase construction consisting of two (2) separate layers of Type 4 and Type 3 Subbase Course.
B.Option B. Subbase construction consisting of a single layer of Type 1 Subbase Course.
C.Option C. Subbase construction consisting of a single layer of Type 2 Subbase Course.
D.Option D. Subbase construction consisting of a single layer of Type 4 Subbase Course.
304-1.03 Definitions. Deleterious: Any material that does not consist of concrete, asphalt, glass, brick,
stone, sand, gravel, blast furnace slag, or other materials deemed acceptable, when these materials are used in subbase in conformance with the specification requirements, OR any material which will adversely affect the performance of the product either during handling, during construction, or in its final application.
304-2 MATERIALS. Provide subbase material meeting the requirements of §733-04 Subbase Course.
Provide a subbase material meeting the specification requirements and is within the Contractor’s capabilities to place and fine grade to the required tolerances. Should the subbase course become unstable at any time prior to the placement of the overlying course, correct the unstable condition at no additional cost to the State. Perform any required modification prior to placing the material on the grade. RAP will not be allowed as an acceptable alternate to Types 1, 3 and 4 at intersection locations or in areas with a high percentage of truck traffic as shown in the contract documents, unless Portland Cement Concrete pavement is to be installed as part of the pavement structure. A high percentage of trucks is defined to be 10% or more. For interstates and other freeways, a DDHV of 250 vph is used to indicate a high percentage of trucks.
304-3 Construction Details.
304-3.01 General. Notify the Engineer in writing of which placement option, material option (if
applicable) and/or material type is proposed for use, at least 14 calendar days prior to performing the work. If it is proposed that more than one option or type is to be used, submit a plan to the Engineer describing where each option or type is proposed for use. This plan must be approved by the Engineer prior to incorporating it into the project. The State reserves the right to disapprove the use of more than
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NEW YORK STATE DEPARTMENT OF TRANSPORTATION Sections 200 - 599 STANDARD SPECIFICATIONS (USC) January 1, 2026 Volume 2 one option on a project. Use uniform subbase types and materials within the limits of the roadbed as defined in §101-02 Definition of Terms.
A.Winter Earthwork. For Contractors choosing to proceed with earthwork construction operations requiring soil compaction from November 1st thru April 1st, provide the Engineer with a Winter Earthwork submittal, with a copy to the Regional Geotechnical Engineer, in accordance with §203- 3.01 A. Winter Earthwork Submittal. In all work incorporated into the final product, the Contractor shall not place material that is frozen, or place fill material on frozen ground. Winter earthwork restrictions for subbase material are such that construction operations may only proceed if the air temperature, ground temperature, and material temperature is above 32° F. Therefore, the Winter Earthwork submittal shall provide details of how standard subbase material will be placed utilizing the modified methods and procedures to adjust for the weather influence on the compaction operations.
304-3.02 Placement.
A.Place the upper course material on the grade in a manner to minimize segregation, using equipment and procedures approved by the Engineer. Do not perform uncontrolled spreading from piles dumped on the grade.
B.The maximum compacted layer thickness shall be as shown in the contract documents. In confined areas, the maximum compacted layer thickness is 6 in. The minimum loose lift thickness is 1.5 times the maximum particle size.
C.Place Type 1 with a minimum compacted layer thickness of 6 in.
D.Do not place Type 3 material within 4 in. of the bottom of a pavement course
E.Do not place materials blended with glass in contact with synthetic liners, geogrids, geotextiles or other geosynthetics. Ensure that glass incorporated into subbase is thoroughly mixed so that glass constitutes no more than 30 percent by weight anywhere in the subbase. When placing material under Option A, place and compact each material in a separate lift.
304-3.03 Compaction. When the moisture content is within the limits for proper compaction, compact
the material in accordance with the requirements of §203-3.03 C. Compaction. Density tests are not required for the acceptance of these courses. If a subbase course is disturbed by frost action prior to paving, re-compact the subbase.
304-3.04 Traffic and Contamination. The movement of highway traffic over the final surface of the
subbase may be permitted at locations designated by, and under such restrictions as shown in the contract documents, provided such movements take place prior to the final finishing of this course to the specified tolerance. Do not allow highway traffic to move over subbase containing glass. The movement of construction equipment on this course may be permitted at locations designated by and under such restrictions as ordered by the Engineer. At locations where permission is granted for such movement, place and maintain the temporary surface of the course, upon which the construction traffic is running, at least 2 in. above the final surface of the course. Just prior to paving and after all construction traffic not required for the removal has ceased, remove the 2 in. protective layer, and prepare and compact the exposed surface of the course to the specified tolerance. No payment will be made for furnishing, placing, maintaining, removing and disposing of the 2 in. thick protective layer. Include the cost thereof in the price bid for Subbase Course.
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NEW YORK STATE DEPARTMENT OF TRANSPORTATION Sections 200 - 599 STANDARD SPECIFICATIONS (USC) January 1, 2026 Volume 2 If the subbase is damaged or mixed with the subgrade or any other material due to the Contractor’s operation, remove such material and replace it with the appropriate subbase material at no additional cost to the State.
304-3.05 Tolerance. Place Types 1, 2 or 4 so that after compaction the top surface of the course does not
extend more than ¼ in. above nor more than ¼ in. below true grade for the course at any location. Place Type 3 course so that the finished surface does not extend above the true grade and surface for this course at any location.
304-4 Method of Measurement.
304-4.01 Subbase Course. The quantity is the number of cubic yards of material, computed from
payment lines shown in the contract documents.
304-5 Basis of Payment.
304-5.01 Subbase Course. The unit price bid for this work includes the cost of furnishing all labor,
material and equipment necessary to complete the work. Include the cost of adding water in the price bid unless the item for applying water is included in the contract. No direct payment will be made for losses of material resulting from compaction, foundation settlement, erosion, or any other cause. No deductions will be made for the volumes occupied by manholes, catch basins and other such objects. No additional payment will be made for the protective layer, as stated in 304-3.04. Progress payments will be made after the subbase course has been properly placed and compacted. Payment will be made at the unit price bid for 75% of the quantity. The balance of the quantity will be paid for after the final finishing to the required tolerance and just prior to the placing of the next course. Payment will be made under: Item No. Item Pay Unit 304.11 Subbase Course, Type 1 Cubic Yards 304.12 Subbase Course, Type 2 Cubic Yards 304.13 Subbase Course, Type 3 Cubic Yards 304.14 Subbase Course, Type 4 Cubic Yards 304.15 Subbase Course, Optional Type Cubic Yards SECTIONS 305 AND 306 (VACANT)
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Source: Standard Specifications (US Customary Units), 2026 (Jan) Edition. Pages 329–331 of 1,489. View official source ↗