Port Authority will keep its $2 base fare while increasing the price of two-zone trips, transfers and weekly, monthly and annual passes starting Jan. 1, under a proposal being made public today.

The agency also unveiled its final draft of sweeping service changes affecting every route.

Authority CEO Steve Bland said the fare increases are designed to spare "the folks with the biggest challenges," who tend to be one-zone riders who pay cash.

"It's also an issue from a convenience standpoint," he said, noting that an increase in the base fare would force customers to carry coins.

The plan is subject to a public hearing Sept. 15 and an authority board vote later.

Authority officials said they needed to raise about $4 million with a fare increase, and previously had speculated that the base fare would rise 10 to 25 cents.

Instead, the following would increase:

• Zone 2 cash fare, up 40 cents, to $3.

• Transfers, up 25 cents, to 75 cents.

• Zone 1 weekly pass, up $2, to $22; Zone 2 weekly pass, up $6, to $30.

• Zone 1 monthly pass, up $5, to $80; Zone 2 monthly pass, up $15, to $105.

• Zone 1 annual pass, up $55, to $880; Zone 2 annual pass up $165, to $1,155.

• Zone 2 book of 10 trip tickets, up $4, to $30; no increase in Zone 1 tickets, now $20.

About 80 percent of the authority's riders use something other than cash to gain admittance to the system -- passes, tickets or senior citizen or student cards.

Mr. Bland said even at the new prices, passes offer riders discounts over the cash fares. "The way I look at it, we're not increasing the price," he said. "We're reducing the discount."

The authority will eliminate its Downtowner zone, meaning rides between Downtown and Station Square, now $1.50, would be charged the full $2 base fare.

The plan also eliminates Zone 3 of the current fare structure, combining it with Zone 2.

On the Light Rail Transit system, Zone 1 riders who use cash during peak periods would pay a $1 surcharge in addition to the $2 base fare. The cash surcharge for two-zone riders would be 50 cents.

The authority last raised the base fare in January 2008, from $1.75 to the current $2. Before that, there had been only four increases in the previous 17 years.