There’s been some news about the I-70/I-71 split through downtown Columbus lately. First, ODOT dropped the ball in communicating with the Columbus City Council and they had to pass some urgent legislation to make sure the project could move forward on time.
ODOT gets earful from council
Phase I legislation will pass despite communication breakdown
Thursday, July 15, 2010 01:39 PM
By GARY SEMAN JR.
ThisWeek Staff Writer
Columbus City Council fully expects to pass legislation authorizing Phase I of the I-71/70 interchange plan, but not before chiding the Ohio Department of Transportation for a breakdown in communication.
At a public hearing July 14, some council members said they were caught off guard by ODOT’s urgent request that the legislation needed to be passed by the end of the month.
Council basically must approve legislation giving the transportation department permission to work in the city’s rights of way, which essentially begins construction of Phase I along 1-670 at Leonard Avenue to Long Street.
…Tom Wester, executive director of ODOT’s District 6, agreed that transportation officials “dropped the ball” in their communication with council. ODOT had been in discussions with the Department of Public Service but had not passed the information along to council.
Nevertheless, inaction by the end of July could cause a two-year delay in Phase I and add $65-million to the overall $260-million cost of the project.
“That’s a lot of money,” he said.
Pending council’s approval, work on the first phase will begin next year and be completed by 2013. ODOT said the fix is needed because of traffic weaving problems and congestion.
Second, the Dispatch had coverage about one of the most coveted aspects of the plan, freeway caps. Only one cap is planned, at Long Street, but all the other retaining walls will be built so that caps could potentially be added in the future.
Coveted highway caps still in Downtown plan
But budget will limit final number
Monday, July 19, 2010 02:51 AM
By Robert Vitale
THE COLUMBUS DISPATCH
Bridges over a rebuilt I-70/71 will be better than the standard concrete and chain-link of today.
But only one of the six spans to be replaced during the project’s first half will include a Short North-style cap that near-Downtown neighborhoods have coveted throughout the planning process.
Ohio Department of Transportation officials say earlier drawings and descriptions were conceptual and now are outdated, even though they’re still posted on the agency’s website. The “visioning exercises” included cost estimates but weren’t subjected to the budget realities applied as the state moves toward a 2011 construction kickoff.
Last, Columbusite identified some inconsistencies with ODOT’s traffic numbers and asked why we’re still using numbers that may be from 2002. This graphic from 2002, which is still on the ODOT website, shows 174,900 vehicles per day on I-70/I-71 east of SR-315 .
However, MORPC’s traffic count database shows a total Average Annual Daily Traffic (AADT) volume at that location of no more than 156,300 in 2003.
So where did the 174,900 number come from?
That’s not clear. I originally guessed that it might be the design volume, based on projected future traffic growth. However, the exhibit is clearly dated 2002 and there’s no mention of 2020 or 2030 traffic forecasts.
UPDATE: I think the difference lies in the subtlety between Average Daily Traffic (ADT) versus Annual Average Daily Traffic (AADT). ADT is for weekdays, while AADT is the sum of traffic for the whole year divided by the number of days in the year. So AADT would be lower due to lighter volumes on the weekends. Columbusite says though that ODOT responded to his inquiry and said that the 174,900 volume on I-70 was taken during construction on I-670. If true, using counts taken during a major construction project that would divert large amounts of traffic to I-70 demonstrates a serious case of poor judgment that should be rectified.
Nevertheless, that does raise some interesting questions. If the volumes were recently as high as 156,300, they could easily return to or exceed that level. Wouldn’t it be appropriate to design for this future growth? What is an appropriate design volume? Do we design for current traffic or future traffic? How accurate are future traffic projections?
In most cases traffic engineers design for traffic volumes at least 20 years in the future. The forecasts usually come from the local Metropolitan Planning Organization (MPO), MORPC in the case of Central Ohio. In my experience, I think that the forecasts generally over-estimate the future traffic volumes based on optimistic growth rates. However, forecasts can also become somewhat of a self-fulfilling prophecy. If you design for 175,000 cars per day you may well get 175,000 cars per day.
In the long run, I think the split probably has enough vehicular demand to fill up whatever space you allow. So unless we want to maximize the number of cars coming into or through downtown, then I’m not sure it makes sense to design to traffic forecasts in this situation. This might be a case where it would be best to design to a budget. If we can’t afford to add two lanes in each direction, then only add one lane, or even no lanes. Maybe correcting some of the safety issues and leaving the number of through lanes the same is a valid option? I suggest reducing the extra car demand with a combination of improved traveler information and economics. By economics I mean adding peak-hour tolls to I-70 so drivers using the Innerbelt will have incentive to car-pool, travel in off-peak periods, or use the Outerbelt instead. Use the revenue to fund transit alternatives.
I don’t think Columbus needs 175,000 cars per day coming into or through downtown. I think 120,000 is plenty. It’s time to think more creatively about some cost-effective solutions for the Split.