The image of a leaping buck or the words "Deer crossing" on a ­yellow sign are so familiar on rural ­Minnesota roads that many drivers don't even notice them. The same goes for "Slow, Children at Play" signs on city streets.

Now drivers may not be noticing that the signs are slowly disappearing in many places across the state.

In Carver County, officials are removing them because, they say, there's no evidence that they cause motorists to slow down, and could give parents a false sense of security.

"The signs that are out there need to be useful," said Kate Miner, the county's traffic engineer. "If we clutter our roadways with signs, it just kind of all becomes background noise after a while."

The changes are part of a new county sign policy commissioners are expected to approve next week. Miner said the removal of some warning signs began a few years ago and will continue through attrition as they are pulled because of fading, damage or roadway upgrades.

Other signs on the way out include warnings about hidden driveways, blind approaches and tractor crossings. Carver County has about 7,400 signs on county roads, Miner said, including regulatory signs, such as speed limits; warning signs, typically yellow with black lettering; and guide signs such as route markers and street names, often green and white.

Miner said the county is ­following the state's example in removing the warning signs, seeking to be consistent with the Minnesota Department of Transportation best-practices handbook for traffic sign maintenance and ­management.

That guide, published in 2010, said MnDOT is also removing numerous warning signs on state roads. Traffic engineers generally agree, the handbook says, "that static signs that warn of infrequent conditions or general possibilities — deer crossings, pavements that are slippery only when wet, rocks that may have fallen, low volume intersections and driveways with limited sight distances — are routinely ignored by drivers."

MnDOT has been taking down deer-crossing signs on state highways since 2005. The reason, said MnDOT state signing engineer Heather Lott, is because there's no evidence that they have reduced deer-vehicle crashes or caused drivers to slow down. The same is true for "Children at Play" signs, she said.

"Use of the signs in some areas would give the false impression that areas without signs do not have children and deer," Lott said.

Other counties are aware of the MnDOT guidance handbook and may be considering similar changes, she said.

A differing view

However, the state Department of Natural Resources takes a different approach. This week, it issued its annual safety reminder about deer, advising drivers to "look for deer-crossing signs that are posted in high-risk areas" to avoid collisions, and to drive with caution in those posted areas.

Motorists reported nearly 7,500 deer-vehicle collisions in the state over the past three years, according to the Department of Public Safety. Large spikes occur in October and November, when deer are on the move during mating season and when deer-hunting season begins.

Maj. Roger Tietz, operations support manager for the DNR's enforcement division, said it's tricky to draw conclusions about whether deer-crossing signs are effective or not. "What you can't measure very easily is the person that read the sign and heeded the advice," he said.

It's possible that drivers may become more alert if they see warning signs, Tietz said, even if they don't slow down. And the number of deer-vehicle collisions in an area may not depend only on whether warning signs are posted or not, he said, but also on the size of the deer population and where deer move, which ­varies from year to year.

Tietz said that safety and signage is a delicate balance, and that both DNR and MnDOT need to be concerned about "over-signage" that can cause drivers to ignore ­warnings.

Children at play

When it comes to signs about children playing, MnDOT's advice is similar: "Watch for Children" and similar warnings should be removed because they have no effect on reducing travel speeds or improving safety. Citing a Wisconsin report, the Minnesota handbook said that the children-at-play signs give a false sense of security to parents and children that may increase risk, and "do not give clear and enforceable guidance to drivers."

Dakota County traffic engineer Kristi Sebastian said children-at-play signs tend to be located more on city streets than on county or state roads. She said Dakota County does not use the signs, but has a few places where county roads are near playgrounds. In those cases, the county uses the playground warning sign with two children on a teeter-totter.

"We're not going to remove those," Sebastian said. "But we do have a practice to remove deer-crossing signs over time."

Signs that work

Miner said Carver County's new policy also will lead to removal of signs such as "Stop Ahead" and "Signal Ahead" that warn drivers about an upcoming intersections that they can already see clearly.

Some warning signs are proven to be effective, she said, and will continue to be used. Most of them caution about curves ahead, sometimes with recommended speeds, and depict a curving arrow, chevron, or squiggly lines to show how the road will turn.

Carver County did a ­special study on its curve signs, and determined that about 7 percent of them were not needed and could be removed without compromising safety, Miner said. Since each sign costs about $200 and lasts for 15 years, the county will save a modest amount of money by not replacing them.

But Miner said budget savings is only an incidental benefit, and the main reason for removing signs is safety. "We need to be sure that signs that are out there and that we do need aren't being overridden by the signs that we don't need," she said.

Tom Meersman • 612-673-7388