According to the European Commission’s estimates, CO2 emissions from heavy duty vehicles, i.e. goods vehicles with a GVW exceeding 3,500 kg and passenger vehicles with more than eight passenger seats, currently represent approximately 25% of the total road transport CO2 emissions in the EU and are expected to increase even further in the future unless measures are introduced to reduce them. For this reason, the European Union are keen to introduce legislative requirements to reduce the CO2 emissions from heavy duty vehicles. This is witnessed by the publication and implementation of EU Regulation No. 2017/2400 on the determination of CO2 emissions and fuel consumption of heavy duty vehicles and EU Regulation No. 2018/932 on the monitoring and reporting of CO2 emissions and fuel consumption of heavy duty vehicles.
Improving the aerodynamic performance of heavy duty vehicles has been identified as one of the key measures that can be introduced to reduce their CO2 emissions and fuel consumption.Both the fitment of aerodynamic flaps to the rear of buses, trucks or trailers and elongated truck cabs with improved aerodynamics can have a significant impact on the aerodynamic performance of buses, trucks and truck / trailer combinations.However, legal restrictions on the maximum overall dimensions of buses, trucks, trailers and vehicle combinations mean that the fitment of such aerodynamic improvements can only be achieved by compromising the vehicle’s carrying capacity, i.e. reducing the length, width and/or height of the passenger / load compartment to keep the overall vehicle dimensions within the specified limits.
Recognising this fact, in 2015, an amendment to the Directive 96/53/EC on the maximum authorised masses and dimensions for road vehicles circulating in international traffic was published. This Amending Directive, (EU) No. 2015/719, introduced relaxations to the maximum authorised dimensional requirements to permit the fitment of retractable or foldable aerodynamic flaps of up to 500 mm in length to the rear of buses, trucks and trailers. This Directive also instructed the European Commission to develop type approval requirements for retractable or foldable aerodynamic flaps and for elongated truck cabs with improved aerodynamic performance which could be introduced into EU Regulation No. 1230/2012 on the type approval requirements for masses and dimensions for motor vehicles and their trailers.
It has taken over three years to develop the necessary requirements, but a draft Regulation containing the new requirements was finally published by the European Commission on 30th January 2019.The draft Regulation, which amends EU Regulation No. 1230/2012, introduces requirements covering deployable aerodynamic devices fitted to the rear of buses, trucks and trailers, deployable aerodynamic devices fitted to the front of truck cabs and elongated truck cabs with improved aerodynamic performance. It also introduces the necessary provisions to allow for the separate technical unit type approval of deployable aerodynamic devices.
For deployable aerodynamic devices fitted to the rear of the vehicle, the draft Regulation specifies requirements on the maximum permissible projection of such devices when in their retracted or folded position, the maximum forces required to retract or fold the device and the minimum vertical and horizontal forces that the device must be able to withstand in its deployed position. The draft Regulation also specifies that the device must not affect the vehicle’s compliance with any other applicable legal requirements. However, the rear deployable aerodynamic device need not be taken into account for the positioning of the rear underrun device if it meets specified design criteria or specified performance requirements on the deformability of the device in a rear impact scenario.
For deployable aerodynamic devices fitted to the front of trucks, the draft Regulation specifies a maximum permissible width projection that the device must meet in both the retracted or folded position and in the deployed position. The draft Regulation also specifies that the device must be covered with energy absorbing material, that is must not impair the driver’s forward vision or the performance of any other vehicle systems and that it must not affect the vehicle’s compliance with any other applicable legal requirements.However, the front deployable aerodynamic device need not be taken into account for the positioning of the front underrun device if it meets specified design criteria on the deformability of the device in a front impact scenario.
For elongated truck cabs, the draft Regulation specifies a three dimensional envelope that the front surface of the elongated cab must fall within. The shape of this three dimensional envelope has been designed to ensure that trucks fitted with elongated cabs falling within the envelope will comply with the applicable turning circle requirements.