3 Terms and definitions

The vehicle(s) that is (are) the focus of a scenario, meaning the vehicle(s) under test. For evaluation of automated driving systems, the Ego vehicle is the vehicle controlled by the system-under-test. For human driver experiments, the Ego vehicle is the vehicle driven by the human driver. There may be zero, one, or multiple Ego vehicles within a scenario.

The use of parameters, which are symbols that may be replaced by concrete values at a later stage according to either user needs or stochastic selection.

A signal cycle starts with the first phase, which is active for the specified duration and switches then to the next phase. The signal cycle is looped, so when the end of the last phase is reached, it continues with the start of the first phase again. The duration of a cycle is the sum of the durations of its phases.

As the signal cycle is part of the dynamic content, it should be specified in ASAM OpenSCENARIO and set in standard-specific elements:

Dynamic signals with exactly the same signal cycle (see signal cycle) can, but are not required to be grouped into a signal group. Two signal cycles are considered the same if they have the same phases (see signal phase) in the same order and therefore also have the same duration. This means a signal group can, but is not required to have more than one element. This allows a signal cycle to be specified only once for the whole signal group. For most use cases this grouping will be done within one intersection.

As the grouping is part of the static content, the signal group should be specified in ASAM OpenDRIVE via the <controller> element.

As the signal phase is part of the dynamic content, it should be specified in ASAM OpenSCENARIO and set in standard-specific elements:

Possible phases could be: go for 5 seconds, caution for infinite seconds, stop for 20 seconds etc.

The semantic state of a signal refers to the rules imposed on traffic obeying the signal at a given point in time. For example, a signal may be in a semantic stop state meaning that obeying traffic must not pass a certain stop line associated with the signal, or it may be in a semantic caution state meaning that obeying traffic may pass the signal but must yield to other traffic and pedestrians as it does so.

The observable state is the physically observable aspects of the state of the signal such as the light bulb state for a traffic light, sound being produced, or messages being broadcast over a vehicle-to-infrastructure communication network. The observable state of a dynamic signal is usually determined by its semantic state, but can be changed independently of it as well. For example, in British Columbia the semantic state go can either result in a flashing green light bulb (if the traffic light is pedestrian-controlled) or in a solid green light bulb. Other examples are the modelling of broken traffic light bulbs (no color at all), or old traffic light bulbs that show different colors than expected (like orange instead of red for the semantic state stop).

The set of possible observable states for a given signal must be inferred from the type and subtype of the signal. Possible observable states may include but are not limited to on, off, flashing for single-bulb traffic lights and red, amber, green for typical traffic lights having three light bulbs

As the signal state is part of the dynamic content, it should be specified in ASAM OpenSCENARIO. The semantic state is set together with its duration using standard-specific elements:

The observable state is also set using standard-specific elements:

As the grouping is part of the static content this should be specified in ASAM OpenDRIVE. Currently there is the t_junction_controller in ASAM OpenDRIVE to set the grouping of signal groups.

Everything that falls within the spatial extent of a scenario and therefore may form a part of the scenario description.