ERYX
'Pegger in Exile
I am a lawyer, albeit a Canadian one so I can't really comment on American law. I am surprised that 10 years is the max for vehicular homicide, usually US sentences are much higher than Canadian. Up here, the max for impaired driving causing death is life. However, the maximums are reserved for "the worst offender and the worst set of circumstances" so usually people get something lower ... Marco Muzzo was sentenced to 10 years for killing a family of four in Ontario few years back. Which seems way too low to me but that tends to be how Canadian criminal justice rolls -- personally I find that minor or marginally criminal offences are given too harsh of sentences, whereas truly horrific crimes get too low. But I digress ...Not a lawyer, but there's two ways to serve multiple convictions: consecutively or concurrently.
Consecutively the sentences are served in order, which is what was described.
Concurrently the sentences are served at the same time, so in this example 10 x 2 would still be 10 years total.
The laws governing concurrently or consecutively varies by state. I think some states allows the judge to decide.
Here, the Supreme Court of Canada ruled consecutive sentences are unconstitutional, so there can only be concurrent sentences. That can be overruled, but it would require parliament to use the Non Withstanding clause to pass a law that would otherwise contradict the Canadian Charter of Rights and Freedoms.
As for consecutive sentences being unconstitutional, not exactly, and it depends on the circumstances. The Supreme Court has said that if offences arise out of a "single transaction" the sentences are to be concurrent. Courts can and absolutely do dole out consecutive sentences when the convictions arise out of separate incidents.