If we are to look at the Vehicle in a bit more detail we can see that it should follow what might be called a classic "project" process. Something like the below illustration where it has distinct phases leading to closure. In this case a simple Initiate, Plan, Execute and Close.

Accordingly, when allocating a Vehicle to do something - in this case to a System, we need to understand what it is to do relative to that System. I have illustrated this below and positioned the Vehicle relative to the lifecycle of a System. In this case the Vehicle is to be used to upgrade the System and is positioned accordingly. So that the Initiate and Plan Phases are complete prior to the "replacement/upgrade window" commences and the Execute Phase overlaps the "replacement/upgrade window".

If we were to look at this from how the project sits, then it would something like the below. Where a project groups the Vehicle and the System and covers both the verb and noun.

So a Vehicle has been allocated to do something to a System and a project purpose has been identified. In this case the project purpose is to "upgrade the system".