Here’s Roadguy’s column from the Sunday paper. If you’ve already read it elsewhere, please skip on down to the comments below.

Freeway drivers tend to have little affection for a lane that’s about to end, but they harbor a great deal of love for exit-only signs.

After last week’s column about the removal of such signs along Interstate 394, several alert readers wanted a better understanding of the Minnesota Department of Transportation’s motivations, so Roadguy got more info from Heather Lott, a MnDOT sign guru.

Lott says that exit-only signs were developed to let drivers on the main part of a highway know that their lane is ending, not to tell drivers entering from a ramp that they’re in a short acceleration/deceleration lane.

“Exit-only signs create a strong reaction from drivers, resulting in many leaving the auxiliary lane immediately, even if they have not accelerated sufficiently to merge into mainline traffic,” Lott wrote, using italics for emphasis. “This defeats the primary purpose of the auxiliary lane.”

So to reduce driver panic, MnDOT has decided that auxiliary lanes that are a half-mile long or longer should get exit-only signs, while shorter ones generally get the “dotted” lane striping and sometimes a black-and-white “right lane must exit” sign. Lott says that, compared with other states, Minnesota had been “overusing” exit-only signs on auxiliary lanes.

Lott encourages drivers entering a freeway to look at the sign near the end of the ramp. An added-lane sign…

…is used for lanes that are going to stick around for a while, whereas a standard merge sign…

…indicates ramp traffic should plan to merge into mainline traffic.

So the answer is still there in black and yellow; it’s just at the end of the ramp instead of overhead.

This entry was posted on Sunday, January 27th, 2008 at 10:45 pm and is filed under Good to know, Main, WUWT?. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.