Even before the E-470 and Northwest Parkway toll highways increase fees Jan. 1, they are two of the most expensive urban roads in the nation to drive.

The financially troubled Northwest Parkway plans to raise the amount drivers pay for riding the full 9.5-mile highway to $2 from $1.75.

And today, E-470's board of directors is expected to choose one of several toll-increase options that have bee under consideration for the 47-mile highway for the past month.

The Northwest Parkway and E-470 are the third and forth most expensive urban-area tollways in the nation an a per-mile basis, according to an analysis by Wilbur Smith Associates, a toll industry consulting firm based in Connecticut.

Only two toll roads - the San Joaquin Hills and the Eastern Transportation Corridor, both in Southern California - charge more per mile.

If E-470's full-length toll goes to $9.75 as expected and the Northwest Parkways goes to $2, motorists on both roads will pay about 21 cents a mile, tying them for the third-highest in the nation after the two California highways.

The urban toll highway category is separate from another that includes intercity toll roads often traversing whole state, such as the New Jersey, Pennsylvania, Ohio and Indiana toll highways.

In Colorado, E-470 directors today will consider increasing the toll at all five of the highway's main toll plazas by 25 cents and a 25-cent increase at five of the road's ramp plazas - those that now have 75-cent tolls.

I directors choose that option, it will increase the toll for riding the full length of E-470 to $9.75 from $8.50. E-470 directors also are expected to consider other options that would make tolls at all main plazas $2 and at ramp plazas 75 cents. That would make the toll $10. Directors may also discount tolls for those paying with electronic transponders.

Officials of both Colorado toll roads say the toll increases are not directly linked to ridership and are necessary to cover payments to investors who paid for construction through their purchase of bonds.

"We have to do the increase to stay on schedule" for the bond repayment, said Steve Hogan, the Northwest Parkway's executive director.

Fitch Ratings, one of the country's three bond ratings agencies, recently warned of the Northwest Parkway's "significantly lower-than-expected traffic and revenue trends."

Fitch estimates toll revenues this year will be only 50 percent to 55 percent of what was forecast.

The toll highway plans to restructure its $415 million in bond debt "to smooth out debt service payments," Hogan said.

The Northwest Parkway's average daily traffic flow ranges from a high of roughly 13,500 toll transactions on Fridays to a low of 6,000 transactions on Saturdays, Hogan said.

Higher tolls on E-470 are required primarily to cover next year's 24 percent increase in debt payments, said John McCuskey, the highway's deputy director and finance chief.

Staff writer Jeffery Leib can be reached at 303-820-1645 or at jleib@denverpost.com.