What makes Virginia different
Drivers cross that line without realising, because on a Virginia interstate the absolute limb can be reached at a margin that would be unremarkable anywhere else. The callout above gives the statutory figures for this state; what matters here is the category change rather than the amount, and the fine schedule on this page does not attempt to price what sits above the line.
Below the line, Virginia is unusually straightforward. The Supreme Court of Virginia publishes a prepayable schedule that charges a fixed amount for each mile per hour over the limit, with a higher rate in a school crossing or a highway work zone, plus fixed court costs. Two drivers cited at the same speed anywhere in the Commonwealth owe the same amount.