Continuances are general a matter of court discretion, but if you haven't previously asked for a continuance that you should be able to get one in this case. Just contact the Court and ask how to request a continuance.
A speeding ticket is a civil infraction hearing. Each hearing officer will handle requests for continuances diffrently. I would suggest that you file your request- it will be up to the discretion of the hearing officer whether to grant the continuance or not.