Judging by your question, I assume your referring to the United States, so I can only really give you my experience from the UK, But I guess it may have some similarities, so first things first, Your medical once that's passed your given your Provisional Learner licence to drive Heavy Goods Class 2 and Class C1 (7.5t vehicles) you can have as much training as you like on the road but can only sit for your practical test, Once you've passed your written theory exams & hazard perception tests, & now the added tests Module 2 & 4 for Driver CPC (Certificate of Professional Competence) your free to take your test and aim for your desired Heavy Goods Licence, The average time in training regarding the learning to drive part here is just 5 days with your test on the final day of training.