Can I just prepay this Reckless Driving ticket?

Unfortunately Virginia does not allow you to prepay a Reckless Driving ticket like you would a speeding ticket.  When you sign that yellow summons, you are agreeing that you will appear in court on the date specified.  If you fail to appear the Judge can issue a warrant for your arrest which will be outstanding until you turn yourself in on the warrant.  Some Judges will convict you in your absence if they think that is more appropriate than issuing a warrant but that is completely in the discretion of the Judge.