Why?
Surely better enforcement of the existing Road Transport Act would be the better course of action. A paltry fine and a few points for using a mobile phone whilst driving does nothing to stop idiots using their phones whilst driving.
If people drive within the rules, and give the road their full and undivided attention, and are courteous to all road users or face much greater consequences (larger fine and more driving bans, such as 3 months first offence) and face a greater chance of getting caught, then the road would be a much safer place, and you would cut road deaths substantially.
The cost of the extra funding for traffic officers would come from the huge savings from not having to shut major routes because some arsehole in a Jag smashed into a barrier on the M6 whilst on his mobile phone and wiped out a family car in the middle lane closing 3 lanes for 4 hours. Those kind of pile ups cost hundreds of thousands if not millions.
We are drifting off the subject of cycling somewhat here, but road users are road users, and being safe saves lives.