Raging about ramps

Ask Minnesotans about their most-hated freeway ramps, and they blurt out such words as "terrible,"horrid,"deathtrap" and "disaster."

Many of those ramps are burdened far beyond their intended capacity and await improvements that may be 10 years or more away.

But even as upgrades proceed on some interchanges, several ramps are headed down the opposite path -- in the past year or so, they've been shortened in order to loosen up the main part of the freeway. "We negatively affect some people to have a much greater good," says Bernie Arseneau, state traffic engineer.

It's all part of a balancing act as metro freeways built in the 1960s struggle to handle the crush of 21st century traffic. Increased traffic volumes in the wake of the Interstate 35W bridge collapse have only added to the challenges.

Complete rebuilds for some of the most congested interchanges are on the drawing boards, but the state's construction timetable extends as far out as 2024 and 2030.

And at ramps hemmed in by topography, drivers may have to make do forever -- or take another route.

'Can't see a thing'

Lindy Richards says she drives about 4 miles out of her way to avoid the ramp from I-35W southbound to I-694 eastbound.

It's a loop that takes drivers uphill, makes them stop at a ramp meter, then puts a yield sign in their path. If they make it past all that, they find themselves in an exit-only lane, so they need to merge left again immediately.

"If you yield, you really can't see a thing. ... They're just asking for a death," said Richards, who commutes from Blaine to Roseville.

The yield sign is a tradeoff. Last year, the Minnesota Department of Transportation took the right shoulder on eastbound 694 and converted it into a lane to help drivers get to northbound 35W.

That east-to-north ramp handles about 1,800 cars during its busiest hour, said Brian Kary, director of freeway operations for the metro area. The ramp that lost its merge zone is used by 200 or 300 cars during the same period.

When the change was first made, there was a spike in accidents, Kary said. But as drivers caught on, the rate dropped to levels more typical for such an interchange.

Another stretch of freeway that has lost space on its ramps is Interstate 94 between downtown Minneapolis and Hwy. 280.

To make room for detoured traffic after the bridge collapse, I-94 was restriped to add a lane in each direction, leaving no room for some merge zones. They're expected to be restored -- and the extra lane removed -- once the new I-35W bridge reopens.

In St. Louis Park, Jeff Cannon describes the Hwy. 7 ramp to southbound Hwy. 100 as "always pretty entertaining, for the wrong reasons." It's a U-shaped ramp with no merge zone at the bottom, so there are all sorts of yield signs, arrows and flags that warn drivers to plan ahead.

On his commute from St. Louis Park to Shakopee, Cannon gets on 100 just upstream from the Hwy. 7 ramp, and he keeps a close eye out for unprepared merging vehicles. Things have gotten a lot better, he said, even in just the past month. "It seems like people are paying attention."

The ramp was redone as part of a project that added lanes to Hwy. 100 last year. Crashes at the Hwy. 7 yield sign haven't dropped from initial levels as much as MnDOT hoped, but they've been cut in half on the adjacent stretches of Hwy. 100, Kary said.

Traffic is flowing better, too. Cannon says his commute from St. Louis Park to Shakopee shrank from 45 minutes to as little as 20 or 25. A complete makeover for that stretch of Hwy. 100 is on the calendar for 2015.

Flyover land? Not so much

In metro areas with more rapidly expanding highway systems, you're more likely to see "stack" interchanges -- ones without loop ramps and where roadways crisscross one another on three or more levels.

Stacks include "flyover" ramps, which take cars up and over the interchange, avoiding the weaving that results with loop ramps.

Some of Minnesota's busiest interchanges were designed a half-century ago, when fewer cars made freeways easier to navigate.

In 1960, when the I-35W/494 junction first opened, it handled 46,500 cars a day; last year, that number was about 267,000.

Tom O'Keefe, MnDOT's manager for the west metro, said that cloverleaf interchanges work OK when two four-lane freeways intersect. If the roads are any bigger, the number of vehicles using the loop ramps becomes too great.

Loop ramps built these days have "longer radii," said Glen Ellis, a design engineer who's been with MnDOT since 1963. The curves aren't as tight on such ramps, and they require less slowing down.

The main reason that cloverleafs persist, Kary says, is money. Flyover ramps are more costly for several reasons -- they tend to take up more land, it's more expensive to build bridges in the air than pavement on the ground, and maintenance is more costly.

Stack interchanges are more common in warmer states, but Kary said winter weather isn't as big a factor because of the success of bridge de-icing chemicals. Snow, however, must be removed from flyover ramps rather than simply plowed to the edge, and that adds to maintenance costs.

Small gains

Sometimes, bad ramps do get better.

The 15-mile-per-hour U-shaped curves that once caused dramatic braking at Hwy. 280 and Larpenteur and Hennepin Avenues are gone, temporarily replaced by a diamond-shaped interchange with more gradual ramps.

A nasty hook of a ramp that once took people from I-35W northbound to the westbound Crosstown Highway was elongated and made less treacherous in the 1990s. And a sharp, short ramp off Hwy. 169 at Medicine Lake Road is scheduled to be lengthened in 2009.

O'Keefe said the Medicine Lake Road project came about in part because of feedback from the public. "That really does help us to identify problems," he said.

But there are some places on the Minnesota highway system where complaints won't do any good, where our beloved landscape simply gets in the way of a good freeway.

From above, the roadways in the Fort Snelling area look like a tangle of hair of the sort you might find on a bathtub drain. Brendan Jutz, who works for the U.S. Fish and Wildlife Service, can see the hairpin ramps from his office.

"All of them are bad," he said, noting that he's seen numerous accidents from his window.

But given the confluence of two large rivers and an abundance of bluffs and historic treasures at Fort Snelling, Jutz says he understands why state transportation officials say there isn't room there to do things differently.

The I-94/694 interchange, just west of the Mississippi River in Brooklyn Center, is similarly boxed in. The junction has seen an increase in traffic after the bridge collapse, and MnDOT recently opened up part of the shoulder on westbound 94 for drivers waiting to go east on 694.

Ellis says they've studied the interchanges there, but with the limited room there are "drawbacks to any possible option."

With the limitations that come with terrain, and the state's funding crunch, it seems there will be plenty of fodder for the name-your-worst-ramp game for eons to come.

As Burnsville commuter Mike Elhard says, "Everybody knows there's a hundred and fifty of them you could choose from."

Jim Foti • 612-673-4491

Jim Foti • jfoti@startribune.com