As the road construction season begins to heat up, the Colorado Department of Transportation (CDOT) is encouraging drivers to obey its signs to “take turns” and help reduce delays when entering construction zones when traffic is congested. 

“Late Merge” signs are part of a traffic control program emphasizing the use of open lanes until a work zone’s actual merge point.  Drivers entering various work zones around the state on multi-lane highways may see signs directing drivers to:  use both lanes during congestion; use both lane to merge point; and take turns merge here.

“When vehicles merge into a single lane too soon, it creates unnecessary backups prior to the work zone and a much higher risk of a crash because vehicles traveling at highway speeds abruptly come upon the rear of a stop-and-go queue,” said CDOT Transportation Systems Management and Operations Director Ryan Rice.  “By using the full capacity of the highway and then taking turns merging down into a single lane, it helps move traffic more effectively.  Our goal is to improve both traffic flow and safety through our projects.” 

Study data have shown that when used properly, the late merge method can shorten queue lengths by as much as 35 percent when traffic is heavy.  Drivers are advised to still merge early when driving through work zones during non-congested periods.

“We appreciate that drivers are trying to be courteous by merging early, but this creates more delays and potentially hazardous traffic back-ups,” added Rice.  “Merge late during congested periods and everyone will save time and be safer.”

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