Sunday, Jan. 29, 2012

40/70 merge to stay 2 lanes

Two lanes really are faster than three, at least where westbound Interstate 40 meets the U.S. 70 bypass of Clayton. And so the state Department of Transportation says an unusual traffic-lane change that it put in place there last September will continue for the next several years.

To make the morning rush hour run more smoothly, the DOT closed one of three lanes on I-40 and one of two lanes on U.S. 70 as it merges with I-40. In September, the DOT called the lane slimming temporary, but on Wednesday, DOT workers installed lane markings to make it semi-permanent. Traffic studies have shown that the morning rush hour runs a bit faster and more smoothly with two lanes there than it did with three, the DOT said.

The DOT added a third lane for a two-mile stretch of I-40 in 2008, when it built the new U.S. 70 bypass interchange near the Wake-Johnston county line. This created a rush-hour bottleneck caused by drivers who move into the new lane as it opens up and then try to squeeze back into the other two lanes when the third lane ends.

So in a very short distance, drivers using two lanes from the U.S. 70 on-ramp and three lanes of I-40 - five lanes in all - had to squeeze back into two lanes.

The DOT's long-term solution is to widen I-40 permanently, from the U.S. 70 bypass of Clayton west to the U.S. 70 Business interchange in Garner, where I-40 becomes three lanes wide for good. The DOT is scheduled to start construction on this long-needed widening project in late 2016. Once the new lanes are completed, by 2021, the lanes that were closed in September will reopen.