analysis of sound

I looked at a short clip from the British T.V drama series 'skins'. Whilst watching this clip I will be analysing the micro feature, sound.
The scene starts of with three boys sitting around a table outside a pop up café. The first thing we hear when the scene starts is the diegetic sounds within the location such as, talking and cars. Whilst the main focus of the scene would be the dialogue with the three boys. From there we here the synchronise sounds of the car hitting the bike and the tyres screeching along the road and smashing into the bollard. From there we see the man driving the car get out and we hear his dialogue as he try's to find a plausible reason as to why he has crashed his car. Throughout the character talking we hear the ambient sound of cars driving past in the background, which has no significance to the scene. However, it allows the scene to have a more naturalistic feel to it as they are on a main road and realistically their would be the sound of cars driving past in the background and by the look on the mans face it is clear he was in a rush to get somewhere which could suggest to us that it is in the morning and he was on his way to work. 
As the scene moves on the main focus is the dialogue which sets out what the scene is about and what is going on. However there is still a lot of diegetic and ambient sound used throughout. Again the fact that the majority of noise used is these two techniques, shows us that the directors intentions were to have the scene come across in naturalistic way and make the scene more relatable to the audience.