ORDER : All the writ petitioners are manufacturers of trailers and semi-trailers. In these writ petitions, the writ petitioners have, inter alia, challenged Notification New Delhi in GSR 212 E, dated 20.03.2015 of the Government of India, Ministry of Road, Transport and Highways amending Rule 126 of the Central Motor Vehicles Rules, 1989. 2. The use of “motor vehicles” is governed by the Motor Vehicles Act, 1988, hereinafter referred to as “the MV Act”, which contains elaborate provisions for registration of motor vehicles; transfer of ownership thereof; purchase of motor vehicles under hire purchase agreements; alteration in motor vehicles; appeals from orders of Registering authorities; control of transport vehicles including necessity of permits such as stage carriage and contract carriage permits; renting of motor cabs; cancellation and suspension of permits; construction and maintenance of motor vehicles; control of traffic including imposition of speed limits; making driving regulations; wearing of protecting headgear; accidents involving motor vehicles; insurance of motor vehicles. The MV Act also provides for constitution of various motor vehicle authorities and Motor Accident Claims Tribunal. 3. Some of the relevant provisions of the MV Act are set out herein below for convenience : “2. Definitions. The MV Act also provides for constitution of various motor vehicle authorities and Motor Accident Claims Tribunal. 3. Some of the relevant provisions of the MV Act are set out herein below for convenience : “2. Definitions. – In this Act, unless the context otherwise requires, - (17) “heavy passenger motor vehicle” means any public service vehicle or private service vehicle or educational institution bus or omnibus the gross vehicle weight of any of which, or a motor car the unladen weight of which, exceeds 12,000 kilograms; (21) “light motor vehicle” means a transport vehicle or omnibus the gross vehicle weight of either of which or a motor car or tractor or road-roller the unladen weight of any of which, does not exceed 7500 kilograms; (22) “maxicab” means any motor vehicle constructed or adapted to carry more than six passengers, but not more than twelve passengers, excluding the driver, for hire or reward; (28) “motor vehicle” or “vehicle” means any mechanically propelled vehicle adapted for use upon roads whether the power of propulsion is transmitted thereto from an external or internal source and includes a chassis to which a body has not been attached and a trailer ; but does not include a vehicle running upon fixed rails or a vehicle of a special type adapted for use only in a factory or in any other enclosed premises or a vehicle having less than four wheels fitted with engine capacity of not exceeding twenty-five cubic centimeters; (39) “semi-trailer” means a vehicle not mechanically propelled ( other than a trailer ), which is intended to be connected to a motor vehicle and which is so constructed that a portion of it is super-imposed on, and a part of whose weight is borne by, that motor vehicle; (46) “trailer” means any vehicle, other than a semi-trailer and a sidecar, drawn or intended to be drawn by a motor vehicle; (47) “transport vehicle” means a public service vehicle, a goods carriage, an educational institution bus or a private service vehicle.” 4. Sections 12, 27, 64, 88(14), 110, 137, 164 and 208 read with Section 211 of the MV Act confers rule making power on the Central Government. In exercise of powers conferred by the aforesaid sections, the Central Government framed the Central Motor Vehicles Rules, 1989. 5. Sections 12, 27, 64, 88(14), 110, 137, 164 and 208 read with Section 211 of the MV Act confers rule making power on the Central Government. In exercise of powers conferred by the aforesaid sections, the Central Government framed the Central Motor Vehicles Rules, 1989. 5. Rule 126 of the Central Motor Vehicle Rules, as it stood prior to its amendment by the impugned notification dated 20.3.2015, reads as follows : “126. Prototype of every motor vehicle to be subject to test.- On and from the date of commencement of Central Motor Vehicle (Amendment) Rules, 1993, every manufacturer or importer of motor vehicles other than trailers and semi-trailers shall submit the prototype of the vehicle to be manufactured or imported by him for test by the Vehicle Research and Development Establishment of the Ministry of Defence of the Government of India or Automotive Research Association of India, Pune or the Central Farm Machinery Testing and Training Institute, Budni (MP), or the Indian Institute of Petroleum, Dehradun or the Central Institute of Road Transport, Pune, or the International Centre for Automotive Technology, Manesar, or the Northern Region Farm Machinery Training and Testing Institute, Hissar (for testing of combine harvester) and such other agencies as may be specified by the Central Government for granting a certificate by that agency as to the compliance of the provisions of the Act and these rules: Provided that the procedure for type approval and certification of motor vehicles for compliance to these rules shall be in accordance with the AIS : 017-2000, as amended from time to time : Provided further that in respect to the vehicles imported into India as completely built units (CBU), the importer shall submit a vehicle of that particular model and type to the testing agencies for granting a certificate by that agency as to the compliance to the provisions of the Act and these rules. So long as there is valid certificate issued by the testing agencies specified under rule 126 during the period it retrofits and so long as retrofitted vehicles meet Mass Emission Norms of year of manufacture of vehicle, retro-fitment by petitioner cannot be put under any restrictions save those arising from the Act and regulations framed thereunder. [M/s.Nugas Technologies India (P) Ltd. v. Union of India, AIR 2002 NOC 70 (Del)]. 6. [M/s.Nugas Technologies India (P) Ltd. v. Union of India, AIR 2002 NOC 70 (Del)]. 6. By the impugned notification dated 20.03.2015, Rule 126 was amended by substitution of the words “including trailers, semi-trailers and modular hydraulic trailer” in place of words “other than trailers and semi-trailers”. After amendment by the impugned notification dated 20.03.2015, Rule 126 reads as follows : “126. Prototype of every motor vehicle to be subject to test.- On and from the date of commencement of Central Motor Vehicle (Amendment) Rules, 1993, every manufacturer or importer of motor vehicles including trailers, semi-trailers and modular hydraulic trailer including registered association (identified by the concerned State Transport Department) for E-rickshaw, wherever applicable shall submit the prototype of the vehicle to be manufactured or imported by him for test by the Vehicle Research and Development Establishment of the Ministry of Defence of the Government of India or Automotive Research Association of India, Pune or the Central Farm Machinery Testing and Training Institute, Budni (MP), or the Indian Institute of Petroleum, Dehradun or the Central Institute of Road Transport, Pune, or the International Centre for Automotive Technology, Manesar, and such other agencies as may be specified by the Central Government for granting a certificate by that agency as to the compliance of the provisions of the Act and these Rules : Provided that the procedure for type approval and certification of motor vehicles for compliance to these rules shall be in accordance with the AIS : 017-2000, as amended from time to time: Provided further that in respect to the vehicles imported into India as completely built units (CBU), the importer shall submit a vehicle of that particular model and type to the testing agencies for granting a certificate by that agency as to the compliance to the provisions of the Act and these rules.” 7. Learned Senior Counsel appearing on behalf of the petitioners, Mr. Kalyanasundaram submitted that before amendment of Rule 126 by the impugned notification No.GSR 212 E, dated 20.3.2015, every manufacturer or importer of motor vehicles other than trailers and semi trailers was required to submit the prototype of the vehicle to be manufactured or imported by him for test by one of the authorities notified in the said Rule. Kalyanasundaram submitted that before amendment of Rule 126 by the impugned notification No.GSR 212 E, dated 20.3.2015, every manufacturer or importer of motor vehicles other than trailers and semi trailers was required to submit the prototype of the vehicle to be manufactured or imported by him for test by one of the authorities notified in the said Rule. However, after amendment, by the impugned notification, trailers, semi trailers and modular hydraulic trailers, which were earlier excluded from the ambit of Rule 126 have been included in the said Rule and are required to conform to the requisites of the said Rule and to submit the prototype of the vehicle for test by one of the authorities notified in the said Rule. 8. Mr. Kalyanasundaram emphatically argued that the petitioners are small scale industrial units for whom compliance of Rule 126 would be a costly affair. The trailer/semi trailer manufacturing industry in the State of Tamil Nadu would be financially ruined by the requirement to get the prototype of the trailers and semi trailers manufactured by them tested by the authorities notified in the said Rule. 9. Mr. Kalyanasundaram argued that ordinarily a trailer or semi-trailer might cost Rs.1 to 2 lakhs, but if the prototype of the trailers and semi-trailers have to be sent to the notified authorities for test and certification, an equal amount or more would have to be spent for each trailer and/or semi-trailer. 10. Mr. Kalyanasundaram argued that trailers and semi-trailers, which are not mechanically propelled vehicles, do not come within the definition of motor vehicle. The Central Government does not, therefore, have the power to amend Rule 126 of the Central Motor Vehicles Rules to include trailers and semi-trailers. 11. In support of his aforesaid submission, Mr. Kalyanasundaram cited a Division Bench judgment of the Punjab and Haryana High Court in The United India Insurance Co. vs. Sh. Pritpal Singh reported in (1996) 113 PLR 49 , where the Court held that trailers and semi-trailers would not come within the definition of motor vehicle, as they do not have any independent identity of their own. 12. Kalyanasundaram cited a Division Bench judgment of the Punjab and Haryana High Court in The United India Insurance Co. vs. Sh. Pritpal Singh reported in (1996) 113 PLR 49 , where the Court held that trailers and semi-trailers would not come within the definition of motor vehicle, as they do not have any independent identity of their own. 12. With the greatest of respect, we are unable to agree with the aforesaid view, since Section 2(28) defines “motor vehicle” or “vehicle” to mean any mechanically propelled vehicle adapted for use upon roads whether the power of propulsion is transmitted thereto from an external or internal source and includes a chassis to which a body has not been attached and a trailer. Semi-trailer has been defined in Section 2(39) to mean a vehicle not mechanically propelled, other than a trailer, which is intended to be connected to a motor vehicle and which is so constructed that a portion of it is super-imposed on, and a part of whose weight is borne by, that motor vehicle. Section 2(46) defines a trailer to mean any vehicle, other than a semi-trailer and a sidecar, drawn or intended to be drawn by a motor vehicle. 13. It is amply clear that though trailer and semi-trailer have separately been defined, they fall within the definition of “motor vehicle” or “vehicle”, since they are connected to and/or drawn by a motor vehicle. In the case of trailers and semi-trailers, the power of propulsion might be transmitted from an external source. As per the definition of motor vehicle and/or vehicle, the power of propulsion might be transmitted from an external or internal source. 14. Mr. Kalyanasundaram, also referred to Section 111 of the MV Act, which confers power on the State Government to make rules. Section 111 of the MV Act reads : “111. Power of State Government to make rules-- (1) A State Government may make rules regulating the construction, equipment and maintenance of motor vehicles and trailers with respect to all matters other than the matters specified in sub-section (1) of section 110. Section 111 of the MV Act reads : “111. Power of State Government to make rules-- (1) A State Government may make rules regulating the construction, equipment and maintenance of motor vehicles and trailers with respect to all matters other than the matters specified in sub-section (1) of section 110. (2) Without prejudice to the generality of the foregoing power, rules may be made under this section governing all or any of the following matters either generally in respect of motor vehicles or trailers or in respect of motor vehicles or trailers of a particular class or description or in particular circumstances, namely:-- (a) seating arrangements in public service vehicles and the protection of passengers against the weather; (b) prohibiting or restricting the use of audible signals at certain times or in certain places; (c) prohibiting the carrying of appliances likely to cause annoyance or danger; (d) the periodical testing and inspection of vehicles by prescribed authorities and fees to be charged for such test; (e) the particulars other than registration marks to be exhibited by vehicles and the manner in which they shall be exhibited; and (f) the use of trailers with motor vehicles” 15. Mr. Kalyanasundaram submitted that Section 111(f) confers power on the State Government to frame rules with regard to the use of trailers with motor vehicles. 16. Mr. Kalyanasundaram referred to Entry 35 of List III (Concurrent List) of the Seventh Schedule to the Constitution of India, which reads : “35. Mechanically propelled vehicles including the principles on which taxes on such vehicles are to be levied.” 17. Mr. Kalyanasundaram argued that the Central Government has power to frame rules under Entry 35 of the Concurrent List only if the vehicle is mechanically propelled. Since the trailer is not mechanically propelled, the State Government alone has the power to frame rules for the trailers. 18. Mr. Kalyanasundaram referred to Rules 350 and 351 of the Tamil Nadu Motor Vehicles Rules, 1989, which provide as follows : “350. Overall length — Exemption.— (a) The overall length of a trailer (excluding any draw bar) shall not exceed 700 centimetres. (b) This rule shall not apply to— (i) a trailer constructed and normally used for the conveyance of indivisible loads of abnormal length. (ii) any agricultural or road making implement. (iii) trailing part of an articulated vehicle. (iv) any incompletely assembled or otherwise disabled motor vehicle. 351. (b) This rule shall not apply to— (i) a trailer constructed and normally used for the conveyance of indivisible loads of abnormal length. (ii) any agricultural or road making implement. (iii) trailing part of an articulated vehicle. (iv) any incompletely assembled or otherwise disabled motor vehicle. 351. Checking designs of locally manufactured trailers,— (1) An application for the approval of a new design of trailer manufactured in India shall be made in triplicate to the State Transport Authority by the manufacturer or his authorised assembler. Such application shall be accompanied by a treasury receipt for the fee prescribed in the Table under rule 368 and three copies of each of the following documents namely:— (i) Full specifications. (ii) Drawing giving all dimensions and details. (iii) Set of design calculations of-— Axles; Springs; Long bearers; Cross bearer. Platform tank or anything that may be carried on the cross bearers; Tow bar and coupling arrangements; Turn table or any other scribbing device for the front axle, in the case of two axle trailers; (h) Braking arrangements, if any; (i) Pay load capacity of the trailers; (j) Suspension arrangements of the trailers over the axle; (k) Turning circle required for the trailers; (l) Sizes and types of tyres recommended for the trailers; (m) Class of motor vehicle drawing trailer (light or medium or heavy transport vehicle); (n) Any other item such as shock absorbers if included. The State Transport Authority shall forward the application together with the accompanying documents to the Deputy Transport Commissioner (Enforcement) who shall then go through the design and calculations and if the design is found satisfactory, certify what would be in his opinion, the maximum laden and axle weights of the trailers which are compatible with reasonable safety. In case the design is not found satisfactory he shall advice the State Transport Authority to that effect and recommend such changes in the design constructions as may be required to make the trailer suitable for the designed load. The State Transport Authority either on its own motion or on the Recommendations of the Deputy Transport Commissioner (Enforcement) under sub-rule (3), may call upon the applicant to carry out such changes in the design as may be specified and to furnish such further details as may be required by that authority. In such case, the applicant shall furnish such further specifications and drawings incorporating alteration, if any. In such case, the applicant shall furnish such further specifications and drawings incorporating alteration, if any. When a design is found satisfactory the Deputy Transport Commissioner (Enforcement) shall forward to the State Transport Authority two copies of the approved design, with his specifications and calculations together with his recommendations as to the maximum laden and axle weights compatible with reasonable safety. The State Transport Authority may approve the design. The applicant shall supply to the State Transport Authority as many extra copies of the approved design specifications and calculations as may be required by that authority for the purpose of distribution to the different registering authorities for their record. The fee paid for the approval of a new design of a trailer manufactured in India shall not be refundable. Explanation.— For the purpose of this rule, the term "New Design" shall mean a design which has not had the approval of the State Transport Authority notwithstanding the fact that a trailer or trailers of such design might have already been registered prior to the 30th March 1960; Provided that nothing contained in this rule shall be deemed to invalidate the registration of a trailer which has already been registered in this State prior to 1st April 1963. (8) The approval of the design of a trailer manufactured in India by a competent authority in any other State in India shall be deemed to be an approval accorded under these rules : Provided that there is in force in that other State, a rule or rules conforming to or containing substantially the same provisions in this rule. (9) This rule shall not apply to ex-army trailers.” 19. Mr. Kalyanasundaram referred to Rule 351(8) in particular and submitted that the approval of the design manufactured in India by the Competent Authority in any other State in India shall be deemed to be an approval accorded under the Tamil Nadu Motor Vehicles Rules, 1989. He submitted that the power to approve the design for trailers and semi-trailers is vested only with the State Government. 20. Mr. Kalyanasundaram referred to Articles 245 and 246 of the Constitution of India, set out herein below : “245. He submitted that the power to approve the design for trailers and semi-trailers is vested only with the State Government. 20. Mr. Kalyanasundaram referred to Articles 245 and 246 of the Constitution of India, set out herein below : “245. Extent of laws made by Parliament and by the Legislatures of States.— (1) Subject to the provisions of this Constitution, Parliament may make laws for the whole or any part of the territory of India, and the Legislature of a State may make laws for the whole or any part of the State. (2) No law made by Parliament shall be deemed to be invalid on the ground that it would have extraterritorial operation. 246. Subject-matter of laws made by Parliament and by the Legislatures of States.— (1) Notwithstanding anything in clauses (2) and (3), Parliament has exclusive power to make laws with respect to any of the matters enumerated in List I in the Seventh Schedule (in this Constitution referred to as the “Union List”). (2) Notwithstanding anything in clause (3) Parliament, and, subject to clause (1), the Legislature of any State also, have power to make laws with respect to any of the matters enumerated in List III in the Seventh Schedule (in this Constitution referred to as the “Concurrent List”). (3) Subject to clauses (1) and (2), the Legislature of any State has exclusive power to make laws for such State or any part thereof with respect to any of the matters enumerated in List II in the Seventh Schedule (in this Constitution referred to as the “State List”'). (4) Parliament has power to make laws with respect to any matter for any part of the territory of India not included [in a State] notwithstanding that such matter is a matter enumerated in the State List.” 21. Mr. Kalyanasundaram submitted that there are around 5,000 manufacturers in India and 250 of them are in Tamil Nadu alone. If they are to approach the notified testing agencies for obtaining the prototype test certificate from the notified testing agencies and the amended Rule 126 of the Central Motor Vehicles Rules, the trailer manufacturing industry will collapse as it is a costly affair and not feasible. Therefore, according to Mr. Kalyanasundarm, the amendment to Rule 126 of Central Motor Vehicles Rules by inclusion of trailers/semi-trailers for design and prototype (model) approval from the notified agencies is unwarranted and arbitrary. 22. Therefore, according to Mr. Kalyanasundarm, the amendment to Rule 126 of Central Motor Vehicles Rules by inclusion of trailers/semi-trailers for design and prototype (model) approval from the notified agencies is unwarranted and arbitrary. 22. Mr. T.N. Rajagopalan, learned Government Pleader appearing for the third respondent “The State Transport Authority” submitted that the amendment of Rule 126 of the Central Motor Vehicles Rules was in accordance with law. He submitted that the testing of the trailer by the notified Authorities who are specialized agencies are only to prevent road accidents. 23. Mr. G. Rajagopalan, the learned Additional Solicitor General for the Central Government submitted that the Central Government has got the powers to frame rules for all Motor Vehicles whether they are mechanically propelled or not. 24. Mr. Rajagopalan submitted, and rightly, that the definition of motor vehicle under Section 2(28) of the MV Act is comprised of two limbs. The first is an inclusive definition, which defines motor vehicle or vehicle to mean any mechanically propelled vehicle adapted for use upon roads whether the power of propulsion is transmitted thereto from an external or internal source, and includes a chassis to which a body has not been attached and a trailer. The second limb excludes from the definition of motor vehicle or vehicle, a vehicle running upon fixed rails or a vehicle of a special type adapted for use only in a factory or in any other enclosed premises or a vehicle having less than four wheels fitted with engine capacity of not exceeding twenty-five cubic centimeters. Trailers, Semi-trailers and Modular Hydraulic Trailers have not been excluded from the definition of motor vehicle and/or vehicle. 25. Learned Additional Solicitor General emphatically argued, and rightly, that the Central Government has got the power to amend Rule 126 of the Central Motor Vehicles Rules under the residuary list. 26. Learned Additional Solicitor General also referred to Entry 97 of the Union list, which is a residuary entry, set out herein below : “Any other matter not enumerated in List II or List III including any tax not mentioned in any of those Lists.” 27. Learned Additional Solicitor General submitted that the Central Government has got the power to amend Rule 126 to include trailers, semi-trailers and modular hydraulic trailers, which also come within the definition of Motor Vehicle. 28. Learned Additional Solicitor General submitted that the Central Government has got the power to amend Rule 126 to include trailers, semi-trailers and modular hydraulic trailers, which also come within the definition of Motor Vehicle. 28. Learned Additional Solicitor General, drew the attention of this Court to Sections 109 and 110 of the MV Act, which contain provisions with regard to construction and maintenance of vehicle and the rule making power of the Central Government. Sections 109 and 110 of the MV Act read as follows : “109. General provision regarding construction and maintenance of vehicles. – (1) Every motor vehicle shall be so constructed and so maintained as to be at all times under the effective control of the person driving the vehicle. (2) Every motor vehicle shall be so constructed as to have right hand steering control unless it is equipped with a mechanical or electrical signalling device of a prescribed nature. (3) If the Central Government is of the opinion that it is necessary or expedient so to do, in public interest, it may, by order published in the Official Gazette, notify that any article or process used by a manufacturer shall conform to such standard as may be specified in that order. 110. Power of Central Government to make rules.- (1) The Central Government may make rules regulating the construction, equipment and maintenance of motor vehicles and trailers with respect to all or any of the following matters, namely :- (a) the width, height, length and overhand of vehicles and of the loads carried; (b) the size, nature, maximum retail price and condition of tyres, including embossing thereon of date and year of manufacture, and the maximum load carrying capacity; (c) brakes and steering gear; (d) the use of safety glasses including prohibition of the use of tinted safety glasses; (e) signalling appliances, lamps and reflectors; (f) speed governors; (g) the emission of smoke, visible vapour, sparks, ashes, grit or oil; (h) the reduction of noise emitted by or caused by vehicles; (i) the embossment of chassis number and engine number and the date of manufacture; (j) safety belts, handle bars or motor cycles, autodippers and other equipment’s essential for safety of drivers, passengers and other road users. (k) Standards of the components used in the vehicle as inbuilt safety devices; (l) Provision for transportation of goods of dangerous or hazardous nature to human life; (m) Standards for emission of air pollutants; Provided that any rules relating to the matters dealing with the protection of environment, so far as may be, shall be made after consultation with the Ministry of the Government of India dealing with environment. (n) installation of catalytic convertors in the class of vehicles to be prescribed; (o) the placement of audio-visual or radio or tape recorder type of devices in public vehicles; (p) warranty after sale of vehicle and norms therefor: (2) Rules may be made under sub-section (1) governing the matters mentioned therein, including the manner of ensuring the compliance with such matters and the maintenance of motor vehicles in respect of such matters, either generally in respect of motor vehicles or trailers or in respect of motor vehicles or trailers of a particular class or in particular circumstances. (3) Notwithstanding anything contained in this section.- (a) the Central Government may exempt any class of motor vehicles from the provisions of this Chapter; (b) a State Government may exempt any motor vehicle or any class or description of motor vehicles from the rules made under sub-section (1) subject to such conditions as may be prescribed by the Central Government.” 29. Learned Additional Solicitor General submitted and rightly that under Section 109 of the MV Act, the Central Government has got the power to issue an order by publication in the Official Gazette notifying that any Article or process used by a manufacture of a motor vehicle shall conform to such standard as may be specified in that order. Rule 126 is in accordance with the powers granted to the Central Government under Section 109 of the MV Act. 30. Learned Additional Solicitor General submitted that the Central Government has been vested with the powers under Section 110 of the MV Act to make rules regulating the construction, equipment and maintenance of motor vehicle and trailers. Therefore, rules relating to trailers regulating their construction, equipment and maintenance can also be framed by the Central Government. He submitted that under Section 111 of the MV Act, the State Government can frame rules only in respect of those matters for which the Central Government has not framed rules under Section 110 of the MV Act. Therefore, rules relating to trailers regulating their construction, equipment and maintenance can also be framed by the Central Government. He submitted that under Section 111 of the MV Act, the State Government can frame rules only in respect of those matters for which the Central Government has not framed rules under Section 110 of the MV Act. In the instant case, rules have been framed by the Central Government amending Rule 126 to include trailers, semi-trailers and modular hydraulic trailers and therefore, the petitioners will have to comply with the same and the amendment is valid in law and the question of conflict between the State and the Central Government does not arise. 31. Learned Additional Solicitor General, then drew the attention of this Court to proviso of Article 254 of the Constitution of India. Article 254 of the Constitution of India reads as follows : “254. Inconsistency between laws made by Parliament and laws made by the Legislatures of States.- (1) If any provision of a law made by the Legislature of a State is repugnant to any provision of a law made by Parliament, which Parliament is competent to enact, or to any provision of an existing law with respect to one of the matters enumerated in the Concurrent List, then, subject to the provisions of clause (2), the law made by Parliament, whether passed before or after the law made by the Legislature of such State, or, as the case may be, the existing law, shall prevail and the law made by the Legislature of the State shall, to the extent of the repugnancy, be void. (2) Where a law made by the Legislature of a State with respect to one of the matter enumerated in the Concurrent List contains any provisions repugnant to the provisions of an earlier law made by Parliament or an existing law with respect to that matter, then, the law so made by the Legislature of such State shall, if it has been reserved for the consideration of the President and has received his assent, prevail in that State : Provided that nothing in this clause shall prevent Parliament from enacting at any time any law with respect to the same matter including a law adding to, amending, varying or repealing the law so made by the Legislature of the State. 32. 32. According to the learned Additional Solicitor General, the proviso to Article 254 (2) of the Constitution of India does not preclude the Parliament from varying the State law. 33. Learned Additional Solicitor General questioned the right of the petitioners to choose the agency to test the trailer and semi trailer and reiterated that in amending Rule 126, the Central Government had neither violated any provision of the Constitution, nor any provision of the MV Act. The amendment had only been made in the interest of safety of trailers, semi trailers and modular hydraulic trailers. 34. In Natwar Parikh & Co. Ltd., vs. State of Karnataka and Others reported in (2005) 7 SCC 364 cited by the learned Additional Solicitor General, the Supreme Court held : “24. Section 2(28) is a comprehensive definition of the words “motor vehicle”. Although, a “trailer” is separately defined under Section 2(46) to mean any vehicle drawn or intended to be drawn by a motor vehicle, it is still included into the definition of the words “motor vehicle” under Section 2(28). Similarly, the word “tractor” is defined in Section 2(44) to mean a motor vehicle which is not itself constructed to carry any load. Therefore, the words “motor vehicle” have been defined in the comprehensive sense by the legislature. Therefore, we have to read the words “motor vehicle” in the broadest possible sense keeping in mind that the Act has been enacted in order to keep control over motor vehicles, transport vehicles, etc. A combined reading of the afore stated definitions under Section 2, reproduced herein above, shows that the definition of “motor vehicle” includes any mechanically propelled vehicle apt for use upon roads irrespective of the source of power and it includes a trailer. Therefore, even though a trailer is drawn by a motor vehicle, it by itself being a motor vehicle, the tractor-trailer would constitute a “goods carriage” under Section 2(14) and consequently, a “transport vehicle” under Section 2(47). The test to be applied in such a case is whether the vehicle is proposed to be used for transporting goods from one place to another. When a vehicle is so altered or prepared that it becomes apt for use for transporting goods, it can be stated that it is adapted for the carriage of goods. The test to be applied in such a case is whether the vehicle is proposed to be used for transporting goods from one place to another. When a vehicle is so altered or prepared that it becomes apt for use for transporting goods, it can be stated that it is adapted for the carriage of goods. Applying the above test, we are of the view that the tractor-trailer in the present case falls under Section 2(14) as a “goods carriage” and consequently, it falls under the definition of “transport vehicle” under Section 2(47) of the MV Act, 1988”. 35. In view of the law declared by the Supreme Court that the definition of the expression “Motor Vehicle” in Section 2(28) of the MV Act is comprehensive, and includes any mechanically propelled vehicle apt for use upon roads irrespective of the source of power including a trailer, we cannot, but, hold that the trailer is a motor vehicle in respect of which the Central Government has power to frame rules. It is not necessary for us to embark upon an academic discussion of the scope and ambit of Article 254 and other provisions of the Constitution. 36. If the intention of the Legislature was to exclude trailers and semi trailers from the definition of motor vehicle in the MV Act, the legislature would have specifically excluded trailers and semi trailers from the definition of the motor vehicle by specifically incorporating trailers and semi trailers in the second limb of the definition specifying exclusions. The trailer/semi trailer, attached to a mechanically propelled vehicle or used for a transportation of goods is a motor vehicle. As argued by the learned Additional Solicitor General, even prior to the amendment of Rule 126 of the Central Motor Vehicles Rules, the petitioners had to obtain the approval from the State Transport Authority, constituted under the MV Act. If a trailer or semi trailer were not a motor vehicle, there would not have been necessity for the petitioners to get approval from the State Transport Authority of Tamil Nadu constituted under the MV Act. 37. The judgment relied upon by the learned Additional Solicitor General in the case of Natwar Parikh & Co. Ltd. vs. State of Karnataka and Others reported in (2005) 7 SCC 364 is squarely applicable to the case on hand. 37. The judgment relied upon by the learned Additional Solicitor General in the case of Natwar Parikh & Co. Ltd. vs. State of Karnataka and Others reported in (2005) 7 SCC 364 is squarely applicable to the case on hand. The Supreme Court in paragraph 24, which was extracted supra, has categorically held that the trailer by itself is a motor vehicle as defined under Section 2(28) of the MV Act. The Supreme Court held that the test to be applied is whether the vehicle is proposed to be used for transport of goods from one place to another. When a vehicle is so altered or prepared to it becomes apt for use for transportation of goods, it can be stated that it can be adapted for carriage of goods. 38. Admittedly, the trailers/semi-trailers, which are in question are used only for transport of goods from one place to another. Applying test held upon by the Supreme Court, the trailers and semi-trailers are Motor Vehicles coming under Section 2(28) of the MV Act. The challenge to the amendment to Rule 126 made by the petitioners is bereft of any merit. The amended Rule 126 is valid and enforceable. 39. The writ petitions are dismissed. However, there shall be no order as to costs. Consequently, W.M.P. Nos. 36202 to 36215, 24632 and 24633 of 2017 are closed.