The Drive: MnDOT adds distance to signs showing travel times

The overhead message boards that display freeway travel times have been extremely popular with Twin Cities metro area drivers since their debut.

But Drive reader Dick points out that one key piece of information is missing: They don't tell motorists how far it is to the destination.

"For the sign to be meaningful and promote safety, warn of a speed reduction and congestion ahead, the sign needed to have both time and distance," he said in an e-mail. "Otherwise the signs are a waste of taxpayer money as they don't provide any guidance to drivers who are not familiar with the named point and have no idea how far away it is, only that it is X minutes away."

The Minnesota Department of Transportation has heard that complaint from other drivers curious about mileage, too.

The agency is slowly responding to the requests, said Brian Kary, director of traffic operations for MnDOT's Regional Transportation Management Center.

About a year ago, MnDOT replaced an old overhead sign on westbound I-94 at Dale Street in St. Paul with a new one that allows for thinner character fonts and tighter spacing of letters. That means there's enough room to include how far drivers have to go to reach Hwy. 280 and I-35W and how long it would take to get there, Kary said.

MnDOT used the sign to test the feasibility of adding the distance component to other signs and to get feedback from motorists. Apparently the test was successful.

In recent weeks, MnDOT started posting both travel times and distance on seven other electronic signs with the higher resolution across the metro area. There are 19 signs that now have the capability, but not all of them will show the new feature.

"The destinations have to be fewer characters to allow room for the destination name and the mileage," Kary said. "'Hwy. 280, 4 MI' is easier to fit on a sign than 'Rockford RD 4 MI.' We want to leave enough room between the destinations listed and the actual travel time for ease of reading as people are driving."

Signs displaying mileage also need space to handle special situations, like Wednesday's snowfall that snarled the evening commute.

With traffic at a near standstill, the sign on eastbound I-494 at Xerxes Avenue in Bloomington didn't display exact travel times. Instead, it told drivers that trip times to I-35W, Hwy. 77 and I-35E would be "over" a specified number of minutes. The word "over" is used when speeds are so slow that MnDOT has a hard time measuring the true speed.

"We have to leave some space on the sign for this 'over' message to appear when needed," Kary said.

By adding distance to the signs, MnDOT can communicate important information to drivers who generally equate freeway driving with the ability to go about a mile per minute.

"Seeing the number of minutes being more than the miles would trigger people to understand there are slowdowns ahead," Kary said.

MnDOT has about 200 electronic signs in the metro area and each has a life span of about 15 years. As they wear out, the department plans to replace them with the higher-resolution signs that can tell drivers both travel time and distance. That will take time, Kary said.

"With the replacement cycle and budget, we are talking a small handful of signs a year that will be replaced," he said.

Follow news about traffic and commuting at The Drive on startribune.com. Got traffic or transportation questions or story ideas? E-mail drive@startribune.com, tweet @stribdrive or call Tim Harlow at 612-673-7768.