I always appreciate motorists who use turn signals to indicate their intent to move into my lane, but am I obligated to let them in?

On a recent afternoon commute, I was on Emerson Avenue, a one-way street with two northbound lanes. When I approached West Broadway in the left lane, I noticed a motorist in the right lane stopped at the intersection with its left turn signal on. I thought she had forgotten to turn it off from a previous turn, but no. She really did want to make a left turn across two lanes of traffic. But by the time I realized her intent I was next to her, and I prevented her from doing so.

As I proceeded through the intersection and continued my northbound journey, I glanced over, and boy, did I catch it: She flashed an obscene gesture and she was mouthing something. I am sure it wasn’t praise for my being a safe and courteous driver.

That incident left me wondering if I was guilty of improper road etiquette. Should I have let her turn?

“Absolutely not,” said John Elder, a spokesman for the Minneapolis Police Department. “When you turn on a signal, what you are doing is asking for the right of way, saying, ‘I want to change lanes here.’ You have the right to slow down and let her in if you want to do that. There is nothing that says you are mandated to do that.”

Elder said I was lawfully sound on what I did, but the offending motorist broke a few laws. Here is a basic primer about using turn signals and changing lanes:

Minnesota law says that a signal indicating a motorist’s intention to make a left or right turn must be given a minimum of 100 feet before a turn and must be displayed continuously until the turn is made. (Drivers exiting a roundabout are exempt.)

Signals may be made using a hand or arm or a light approved by the Commissioner of Public Safety. If a vehicle is constructed or loaded in a way that hand signals are not visible in normal sunlight or at night, then the signals must be given by a light.

Once the turn is properly signaled, the turning motorist shall abide by the following rules:

Right turns should be made as close as possible to the right-hand side of the roadway.

Left turns on a two-way road should begin from the right side of the centerline and end on the right side of the centerline of the road being entered.

Left turns from a one-way road onto a two-way road shall be made from the left lane and end up on the right of the centerline of the roadway being entered.

Motorists have the right of way for the lane they are in, said Sgt. Jesse Grabow of the Minnesota State Patrol. Those changing lanes need to “yield the right of way” for traffic already in line, he said. Drivers should not have to take evasive action because somebody decides to change lanes at the last second, Elder said.

“You have the right for what the lane was designed for,” he said. “It’s a courtesy to let them in.”

More egregious than the signaling error was the woman’s outburst, he said, which technically was road rage.

“This person is a little whipped up and obviously lost her head somewhere,” Elder said. “It’s not your fault for not bending over backward to let her have access to the road.”

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