Considering that these folks want a sizeable slice of the consumer's purchasing power every month for the privilege of living in Johannesburg or Pretoria, they are actually increasing the CPI. This is a vicious cycle, and it would be interesting theoretical exercise to work out how long before toll tarrif increases become the primary driver of CPI. It's theoretical, of course, because the money that they are "owed" exists only in the minds of their accountants and greedy investors.