Right arrow, D or tap the gas to move the car forwards. Before you say it in the comments, yes, I am aware that air resistance isn't fully implimented yet. I will get to implimenting it soon, do not worry. ACCEL ADJUST CALCULATION UPDATE!
I'm not the kind of guy to go take things and claim them as my own, so I would just like to thank @Car_Lover_321 for the simulation. It is possible to go faster than 999 MPH by changing the code, but it is a little bit buggy because the numbers poke out of the box a bit.