The Volvo line is an imaginary line between the more liberal big government nanny state mindset of the higher population density in the southern part of the state, and the more rural traditionally Independant Mainer. The stereotype is of the middle-aged ponytail wearing college professor or the affluent Massachusets transplant, The Volvo's and Saabs seem to be some sort of status symbol to these groups, like a secret handshake. Its kind of a joke, but not really, there IS two Maines.
Disclaimer: To anyone reading this from southern Maine, I understand that not ALL from Augusta south are like that
LOL just googled two Maines, its all right there