How do I convince my parents to let me buy another car?

For context, I am a 19 year old male student. Previously I did buy a car but it turned out to be a scam - there was so much rust below it there was no way it would ever pass an MOT again (solution included welding etc). I cannot handle public transport at all - so I am always walking everywhere or getting a lift to places or a taxi/uber on rare occassions. When I found out about my old car my dad was not very pleased about it saying that I've wasted my money etc. So - I agreed a plan - I would simply cut back on my expenses until I had saved up enough money to buy another car. I am very nearly on the verge of finishing saving up and I also came into a bit of money last summer but the trouble is I need to convince my dad that it is the best thing. I am sick of walking everywhere (I stopped taking buses to save money for said new car) and I have also applied to part time jobs and internships over the summer so I will have plenty of ways of earning this money back. How do I get him to be convinced it is the right decision?