Special vehicles that are exempt from being required to have direction indicator lights are those where directional changes can be signaled with the arm. This is because these vehicles, being able to use the arm to indicate their intentions, do not need to rely exclusively on lights to communicate their movements to other drivers.

In contrast, vehicles that exceed certain weights or dimensions, such as those whose **MMA (Maximum Authorized Mass) exceeds 4500 kg**, are not exempt from having indicator lights, as their size and weight require additional safety measures to ensure that their movements are clearly visible to other road users.

On the other hand, vehicles performing **agricultural work** are not exempt from this obligation simply due to the nature of their work. The regulation focuses on the ability to manually signal as the criterion for exemption, not on the type of work the vehicle performs.