i have just cancelled my visa application however had submitted a tourist visa online and ticked "yes" to convictions due to a driving related offence.
i have since done lots of research and see that a visa may not be necessary. i have completed ESTA form and been accepted for visa waiver programme.
will US immigration know i have submitted and cancelled a visa application? as i am due to travel to New York in November and do not want to be turned away
If your driving offence is such that you are eligible for a visa waiver, then you are eligible for a visa waiver. It really doesn't matter that you mistakenly put in and then withdrew a visa application.
I doubt if they will know - they would (probably) if you had been refused a visa but not if the application were never considered.
If they do know, it's easily explained - you misunderstood the requirement for a visa.