GRAND RAPIDS, MI --In this week's Ask a Trooper, state police Lt. Rob Davis talks about a favorite topic of many: last-minute mergers. Or, are they actually helping traffic flow as "zipper" mergers?

Have a traffic question? Email Lt. Rob Davis and the troopers at the Lakeview and Rockford posts at MSP-AskTpr@michigan.gov

Lt. Rob Davis: So...you're a "rule follower" like me and you see that the left lane closes ahead due to a construction zone, so you merge to the right the first chance you get, and then the traffic slows to a stop and go. As you wait your turn in line to enter the zone, you watch as other cars zip by you and then merge (cut) at the front of the line.

As frustrating as it is, there is nothing that prohibits people from doing this. They are however responsible for merging safely and have to yield the right-of-way to through traffic.

I have observed where aggressive drivers will angle their cars into the merge lane between two vehicles, essentially forcing a merge by threatening an accident.

This is either careless driving or improper lane use, either way it could end in a citation. If you're that person who's passed everyone and you get stuck at the front of the zone, you'll have to leave your blinker on until someone lets you in or a suitable space opens for a safe merge.

I've receive numerous e-mails from people who claim that going to the front of the line is more efficient for traffic flow in this situation. I believe that they're right, but it requires that everyone follows a zipper merging pattern (where vehicles take turns merging).

We all know that it only takes a couple of people not to follow the pattern and we're right back to the single lane merge. I know in the past MDOT has used signs to help instruct people on the zipper concept and I believe they had positive results.

I cannot answer why it's not used all the time, but like other traffic issues, I know that engineers set the zones up to be as safe as possible based upon numerous criteria.

I hate to add your frustration, but you know that guy or gal usually a commercial driver who jumps in the left lane to block those people from cutting, he too is in violation. Sorry, but that action is considered a lane use violation and/or obstructing traffic. I certainly understand their intentions, but they should not take it upon themselves to try to control traffic flow.

There is no easy answer for this "bottleneck" situation, other than to remain calm and courteous. I have experienced times where I wasn't sure which lane was closed and ended up feeling like I was cutting. Some polite person always lets me in and I return the favor, even to those who race to the front.

Thanks for reading.