A Life-time driving ban is availabl as an option for some convicitons.
When someone is faced with having commited a crime of which there are miltiple chargers available, the CPS will aim for the highest charge that has the best chance of conviction. She could have been charged with Murder or manslaughter but the chance of a convicition would have been too slim to make chasing it a possability - bearing in mind the "beyond all reasonalbe doubt" benchmark needed in a court of law.
What does happen a lot of the time though is that th person themselves will admit, or plead guilty to a lesser charge. This is where it becomes tricky. If the CPS decide to decline this lesser charge admitance and push for a higher charge, then they are in fo all or nothing. Fail to get the higher charge and they walk, get the higher and they are banged.
So in the case of a lot of Drink Driving that involves a death of someone, manslaughter would prob be the highest that on paper they could go for (someone causing or permitting the death of another, but without pre-medietation - to paraphrase),
But when they please guilty to TWOC, DD or dangerous driving then CPS will often look at he balances of probabilities, the preseidents set by previous cases, and see what they can go with.
If punishments scaled from 1 (slap on the wrist /suspended sentence) through to 10 (life without parole) then a higher charge conviction could get you a level 6 - 8, but the chance of getting it is 10 - 20%, but guilty admittance to the lesser charge with a convicition level of 3 - 5 that is 100% then where are they going to go?
It is not nice, nor right, but it is how they system works, and how Mr Loophole Lawyer earns his living.
As for the 50% rule, the other 50% is on licence, whereby they can be racalled to serve the rest should anything happen during their out half. So, maybe she might get out, and 6 months later go out and something happend for which normally a caution, ora fin, but no - pulled back for the other 2 1/2 years.
Not to detract that the families have my sympathies due to one young persons' minute of drunken stupidity, which no imprisinment etc can ever bring them back.
People scoff when people are not "sent down" but in reality, if you do, they will cost the tax payer £40,000 + PA to keep them there, they are secured away and protected from the general public, do not have to face their daily scorn, the living without a car, taking public transport, turned down from jobs, being refued this and that and eventualy, when they do come out (besides an involved few) who will remember who they are? Will there be a new thread on here that "Beth Makay has been released"?
Sending someone down should, and is, only reserved for those that pose a danger to the public. Most sentences can be served "in the public", open prisions etc etc as although what they have done is wrong, very wrong, but in general they are not a risk to the general public, people they pass in the street etc. Is someone who embessled £4m from a bank a threat to the people in the park?