I agree with Mr. Meehan.
In my area, the worst offenders in terms of driving while holding onto a cell phone are women driving HUGE SUVs, and they can usually be counted on to exhibit some really poor driving skills. As Joseph theorizes, they may be trying to protect themselves with as much mass as possible.
It seems that at least once each day, I will see a women driving a Nissan Armada (the vehicle so big that it needs a term previously reserved for a naval fleet in order to describe it), or its Infiniti clone, while holding a phone to her ear and also tailgating another vehicle dangerously close. These vehicles are large when compared to even some SUVs, and are absolutely gargantuan when compared to small sedans and coupes. And yet, the folks who seem to be piloting these monstrosities invariably seem to be small, very distracted women with poor driving skills.
Talk about a really deadly combination of factors!