The rapid development of low-emission drivetrains is leading more and more truck manufacturers to introduce electric or hydrogen-powered vehicles into their offerings. It is becoming increasingly likely that we will soon see a growing number of such vehicles on the roads, transporting various types of cargo. Until recently, electric and hydrogen vehicles were not permitted for the transport of dangerous goods such as fuels, chemicals, and similar materials. However, this changed with the latest version of the ADR regulations, effective from the beginning of 2025.

ADR – in brief:

ADR is an international agreement that regulates the road transport of dangerous goods. It includes the classification of goods, packaging requirements, labeling, documentation, certification, safety procedures, and technical requirements for both vehicles and drivers. It is the primary regulatory framework for such transport across Europe. The official Polish language version of the ADR agreement is published in the Journal of Laws.

ADR defines four categories of vehicles designated for different materials based on their classification in Table A of the ADR:

• EX/II and EX/III: vehicles designed for the transport of explosives and related items (Class 1)
• FL and AT: vehicles intended for the transport of other flammable liquids and gases in tanks, tank containers, or multiple-element gas containers (MEGC)

Until now, electric and hydrogen vehicles could not be approved for ADR transport at all. The version effective from January 2025 now allows for approval in FL and AT categories. However, vehicles carrying explosives (EX/II and EX/III) are still not permitted to use electric or hydrogen drivetrains.

The construction requirements for vehicles under ADR are also outlined in UN ECE Regulation R105, issued by the United Nations Economic Commission for Europe. This is the official document that sets unified technical standards for the type approval of vehicles used to transport dangerous goods. If a vehicle passes the homologation tests and meets the R105 criteria, it can be ADR-certified for transporting such cargo. Regulation R105 is currently awaiting updates to align with the revised 2025 ADR agreement.

Key R105 Requirements for ADR-Approved Trucks Include:

• Proper protection of electrical circuits to prevent sparking
• Additional insulation of electrical wiring and shielding of low-voltage battery terminals
• A safety cut-off switch in the vehicle cab that must shut down the vehicle within 30 seconds of activation
• All continuously powered devices (even after the safety switch is activated) must be adapted for operation in hazardous areas and comply with the relevant parts of IEC 60079 standards (e.g., a tachograph in an ADR-compliant version)
• The braking system must comply with UN ECE Regulation R13
• Trucks must be fitted with a speed limiter not exceeding 90 km/h

ADR Requirements for Electric Vehicles

Electric trucks must meet the same general ADR requirements as internal combustion vehicles, but additional criteria apply:

• The drivetrain system, including the battery system (REESS – Rechargeable Electrical Energy Storage System), must comply with UN ECE Regulation R100.03 – the latest standard for the type approval of vehicles concerning specific safety requirements for electric propulsion systems. This regulation ensures maximum safety of traction batteries and high-voltage components.
  Note: Ennovation has experience in certifying batteries according to R100.03.
• Electric vehicles must be equipped with insulation resistance monitoring systems.
• The charging socket must include additional temperature sensors, which can limit or shut off the charging current in accordance with ISO 17409:2020, in case temperature thresholds are exceeded.

ADR Requirements for Hydrogen Fuel Cell Vehicles

Trucks powered by hydrogen fuel cells must meet all the requirements for electric vehicles, plus additional hydrogen-specific criteria:

• The hydrogen system must comply with UN ECE Regulation R134.02, which contains uniform technical prescriptions for type approval regarding the safety of hydrogen-powered vehicles.
  Vehicles using liquid hydrogen must also meet the requirements of GTR (Global Technical Regulation) No. 13, meaning hydrogen tanks and related components must comply with the most stringent safety standards.
  Regulation R134.02 includes extreme safety testing such as:
  • Mechanical strength tests
  • Fire resistance tests (Annex 3 of R134.02)
• Hydrogen vehicles must also be equipped with automatic shut-off valves for hydrogen cylinders in the following scenarios:
  • The vehicle is not in drive mode
  • The vehicle decelerates sharply (more than 8.2 km/h in 0.7 seconds – corresponding to 3.25 m/s²), indicating a potential collision
  • The vehicle tilts sideways at an angle greater than 23°

Summary

The additional requirements for electric and hydrogen-powered vehicles are designed to ensure the highest level of safety when transporting dangerous goods. Allowing zero-emission vehicles to be ADR-approved under the new 2025 regulations is a significant step forward for the future of emission-free heavy-duty road transport.