Vehicles should arrive at vehicle depot as the replacement reaches 100%

Right now the way it works is when you slot a vehicle for upgrade, it will wait until the replacement is completely finished, and only then it will start driving towards the depot. This is extremely inefficient because it can take a while to drive to the depot. So if you have a queue of vehicle upgrades, it adds a ton of time in between each one because the depot will be sitting there waiting for the vehicle being replaced to show up and it does not work while waiting. This process becomes excruciatingly long while upgrading excavators, since they will take a long time to drive to the depot. This can sometimes add minutes of idling in between each vehicle production.
Maybe another way you could fix this problem would be allowing the depot to continue working on the next vehicle, and the finished vehicle can sit waiting outside for the driver to arrive (and thus not add to logistic max since it's just sitting parked)