The 3D videos prepared by the Arkansas Highway and Transportation Department
to allow viewers to compare the 8-lane options for Interstate 30 to the 10-lane options (called 6+4 for various reasons by the AHTD, one of them possibly to get around the requirement to get Metroplan to amend its 6-lane limit on I-30) show such a dramatic difference — with traffic at a near standstill with 8 lanes and moving quickly with plenty of room between cars on the 10-lane — that I called the highway department's design build project engineer, Ben Browning
, and asked why.
Browning explained at the public hearing on Tuesday night that it was because the collector/distributor lanes that make up the four lanes of the 10 lane plan are removing 80 percent of the traffic off the interstate's thru traffic. He also said the models used in creating the videos, which compare traffic at the evening rush hour in 2041, took into account induced demand — that more people will choose to use I-30 because, at first, it won't have congestion, though given what the 8-lane video shows and the fact that there are alternatives to cross the river, I can't imagine anyone choosing I-30 under that scenario.
We don't know how much "induced demand" the AHTD factored into its models. But Browning told me there is another factor making the 2041 traffic in the 6+4 scenario appear to be such smooth sailing: It assumes that Interstate 30 south of its interchange with I-530 and I-440 will be widened all the way to 65th Street, I-30 becoming three lanes rather that the current two at that conjunction.
That stretch of interstate is not part of the 30 Crossing project; 30 Crossing stops at 530 and 440. Widening of I-30 from there to 65th Street is unfunded. But the widening of I-30 to 65th Street — included in both 8- and 10-lane models — was included because "there is a likelihood that widening could happen in the future," Browning said, and that such widening could be recommended by AHTD next year. On the other hand, the AHTD took out the widening of I-630 to University as an assumption because it was not
likely to be funded.
What if that widening never occurred? Browning said that southbound traffic on I-30, even with the 10-lane alternative, would be "significant."
It seems to me the videos should have included information on all the traffic data assumed for them.
The AHTD 30 Crossing website also includes
an image called the "8-lane general purpose backup," showing that only two northbound lanes connect with I-40 traffic under that scenario rather than three lanes under 10-lane plan.
Here's the PDF of that image.
So what would happen if rather than two lanes, a third lane for northbound traffic onto I-40 were added? "You're getting away from the 8-lane mentality at that point," Browning said. The AHTD didn't model it to know whether that would make a difference in the bumper-t0-bumper traffic under the 8-lane scenario.
At any rate, if the AHTD is to assume I-30 will be widened from 440 and 530 to 65th Street, what happens west of 65th Street? Or is that assumed as well? And if I-30 is widened all the way to Benton, will that put pressure on Interstate 430? And if it does — well, you see the logic here. Pushing bottlenecks down the road might make for a nice video of swift rush hour traffic in Little Rock, but what does it do elsewhere?
PS — As we wrote yesterday, the powers-that-be have agreed to go in the tank on the latest iteration of the 10-lane-plus concrete chasm through the heart of Little Rock. Any time the establishment has cut a deal, you can expect the Little Rock Regional Chamber of Commerce to be in their orchestrating the string-pulling. No different today. They naturally join the Big Lie PR strategy of the Freeway Department in calling it a six-lane freeway with four lanes of collectors. Even in Arkansas that adds up to 10, and as noted, sometimes more.
Here's the chamber's pitch.