What is  ISO 3691-4 about?  
ISO 3691-4 discusses safety requirements for industrial trucks. ISO 3691-4 specifies safety requirements and the means for their verification for driverless industrial trucks (hereafter referred to as trucks) and their systems. ISO 3691-4 also contains requirements for driverless industrial trucks which are provided with:
- Automatic modes which either require operators’ action(s) to initiate or enable such automatic operations
- The capability to transport one or more riders (which are neither considered as drivers nor as operators)
- Additional manual modes which allow operators to operate the truck manually; or
- A maintenance mode that allows manual operation of truck functions for maintenance reasons 
Note 1: It does not give requirements for additional hazards that can occur:
- During operation in severe conditions (e.G., Extreme climates, freezer applications, strong magnetic fields)
- During operation in nuclear environments
- From trucks intended to operate in public zones (in particular ISO 13482);
- During operation on a public road
- During operation in potentially explosive environments
- During operation in military applications
- During operation with specific hygienic requirements
- During operation in ionizing radiation environments
- During the transportation of (a) person(s) other than (the) intended rider(s)
- When handling loads the nature of which can lead to dangerous situations (e.G., Molten metals, acids/ bases, radiating materials)
- For rider positions with elevation function higher than 1 200 mm from the floor/ground to the platform floor.
Note2: ISO 3691-4 does not contain safety requirements for trailer(s) being towed behind a truck.
Note3: ISO 3691-4 does not contain safety requirements for elevated operator trucks.
Who is  ISO 3691-4 for? 
ISO 3691-4 is of relevance, in particular, for the following stakeholder groups representing the market players with regard to machinery safety:
- Machine manufacturers (small, medium, and large enterprises)
- Health and safety bodies (regulators, accident prevention organizations, market surveillance, etc.)
- Machine users/employers (small, medium, and large enterprises)
- Machine users/employees (e.G., Trade unions, organizations for people with special needs)
- Service providers, e.G., For maintenance (small, medium and large enterprises)
- Consumers (in the case of machinery intended for use by consumers). 
Why should you use  ISO 3691-4?  
 For the purposes of ISO 3691-4, a driverless industrial truck is a powered truck, which is designed to operate automatically. A driverless truck system comprises the control system, which can be part of the truck and/or separate from it, guidance means, and power system.
In order to properly design a product and to cover all specific safety requirements, the manufacturer needs to identify the hazards that apply to their product and carry out a risk assessment.
ISO 3691-4 specifies safety requirements and the means for their verification for driverless industrial trucks (hereafter referred to as trucks) and their systems.
ISO 3691-4 deals with all significant hazards, hazardous situations or hazardous events during all phases of the life of the truck (ISO 12100:2010, 5.4) to the applicable machines when it is used as intended and under conditions of misuse which are reasonably foreseeable by the manufacturer.
What’s changed since the last update? 
BS EN ISO 3691-4:2020 supersedes BS EN 1525:1998, which is withdrawn.
