Study improves 25th Street traffic flow
by RICK NORTON Associate Editor
Feb 28, 2014 | 1462 views | 0 0 comments | 27 27 recommendations | email to a friend | print


Signalization changes made to 11 intersections along the 25th Street Corridor have reduced traffic delays 10 to 39 percent and decreased motorists’ travel time from one end to the other by 5 to 21 percent.

But, further improvements may have hit a red light until more lanes are added.

That’s the assessment of a long-awaited “Traffic Signal System Evaluation and Timing” study that has been completed for the major four-lane artery that a Knoxville traffic engineer on Thursday called “... the most important east-west roadway in Bradley County.”

He tempered the claim by citing the co-importance of U.S. Highway 64.

“We’ve got things operating pretty well right now, but my concern is five, 10 years beyond and down the road as traffic continues to grow,” Alan Childers, who heads up the Cannon & Cannon Inc. traffic control division, told members of the Cleveland Board of Public Utilities.

“There’s going to be some issues,” he added. “You can only do so much with signals. You need [more] lanes sometimes.”

Although devising a strategy for adding new lanes to any of the busy junctions was not a part of the contracted study for Cleveland Utilities, the Cannon & Cannon engineer cautioned this will be a real need if Cleveland’s rapid growth continues over the next few years.

Similar to a study conducted a couple of years ago by the same firm along Paul Huff Parkway, the 25th Street project was charged with evaluating the entire stretch of thoroughfare from Spring Creek Boulevard to Candies Lane/Executive Park Drive. The study focused on all 11 intersections and changes to their signalization patterns and cycles that could enhance traffic flow.

“This was accomplished by evaluating traffic signal operations and implementing appropriate signal operational and phasing changes, and by implementing optimized traffic signal system timing,” Childers explained. “In addition, the study identified some potential future roadway improvements that would benefit the corridor.”

“Roadway improvements” is traffic engineering code for “more lanes.”

“The corridor is [now] benefiting from traffic signal operational modifications such as signal phasing and timing improvements,” he said.

And then Childers repeated the caveat, “... A variety of roadway and intersection improvements will be needed in the future to address both short- and long-term traffic growth.”

Improvements implemented to the 25th Street Corridor (also known as State Highway 60, 25th Street and Georgetown Road) as part of the vast study include so far:

- Lead-lag left-turn phasing (which refers to the sequencing of left-turn arrows and when they come up in a traffic signal’s cycle) was completed at two key locations: 25th Street and Chambliss Avenue in the westbound left-turn lagging; and 25th Street and Julian Drive in the eastbound left-turn lagging.

- Signal clearance (yellow and all red) modifications at all intersections to provide consistency and to improve safety.

- Five systemwide signal timing pattern plans implemented to address different traffic conditions (such as Friday traffic; morning, midday and afternoon rush hours; and night and weekend traffic conditions).

- Short duration “special split plans” implemented at several intersections to address short-term traffic needs (such as school start-up and let-out times, and others).

- Initial implemented timings were tweaked in conjunction with Cleveland Utilities staff observations and staff assistance.

Prior to the Cannon & Cannon study, CU traffic coordinator Tad Bacon had already worked meticulously to monitor 25th Street traffic flow and to tweak the existing system in anticipation of a more thorough evaluation by the Knoxville consultant.

One proposed signal improvement that has not yet been implemented — because of its radical change and an accompanying cost factor — is the use of “Flashing Yellow Arrow” phasing. This is a new concept in left turns that is quickly becoming a new standard across America. Childers said 42 states have now adopted it as a standard. Tennessee is one of eight that has not.

But in Childers’ words, “... It is coming.” That’s because most traffic engineers agree it is a better traffic direction indicator and it is safer. The problem is that it is “different” and will require motorist education and a public awareness campaign before implementation.

Currently, Cleveland intersections are governed by a 5-section “Doghouse” signal head that allows for left turns on a green ball, green arrow or perhaps a yellow ball. The new standard calls for a reconfigured, vertical signal head that shows steady red at top, steady yellow below it, a flashing yellow arrow below that and finally a steady green at the bottom.

Under the flashing yellow arrow, a motorist may make a left turn, but it is not protected.

Childers said the flashing yellow arrow is considered more visible and therefore is considered a safer alternative. It explains why 42 of 50 states have accepted it as a new traffic signal standard.

“People are more cautious with flashing yellow arrows,” he noted. Childers said other states and communities where the flashing yellow arrow has been implemented are reporting a 20 to 30 percent reduction in traffic accidents.

“That’s pretty significant,” he said.

But, Cleveland is not yet ready for it and it’s not just because of public awareness.

“We’re looking at some operational issues,” Bacon said. “[Our] wiring is outdated. It’s older ... we’ll need to make some other improvements and we’ll have to look at some funding.”

Childers said existing controllers can be converted, but in the case of Sevierville, the upper East Tennessee town is waiting to acquire new-generation controllers before embracing the flashing yellow arrow.

But they will be coming to the tourist hamlet ... and eventually to Cleveland, probably.

Until then, what improvements has the 25th Street Corridor study achieved? Childers documented them in the CU board presentation. All are based solely on signalization changes. No physical roadway improvements were included.

Under vehicular delays (a reference to periods when a motorist is sitting idle) along 25th Street, the improvements include:

- Morning peak hours: 34 percent improvement eastbound and 10 percent westbound;

- Midday peak hours: 24 percent improvement eastbound and 33 percent westbound; and

- Afternoon peak hours: 39 percent improvement eastbound and 27 percent westbound.

Under travel time (a reference to the amount of time required to travel from Spring Creek Boulevard to Candies Lane/Executive Park Drive and vice-versa):

- Morning peak hours: 13 percent improvement eastbound and 5 percent westbound;

- Midday peak hours: 11 percent improvement eastbound and 17 percent westbound; and

- Afternoon peak hours: 21 percent improvement eastbound and 18 percent westbound.

“These are pretty big improvements,” Childers said. “They’re on the high end.”

Improvements are not tied just to reduced traffic delays and travel time, he stressed. Other benefits are the environment and fuel cost.

Using a U.S. Highway Administration formula for accepted economic benefits, Childers estimated an annual benefit for delay reduction worth $947,229, and an annual benefit for emissions and fuel reduction of $143,996. This totals $1,091,225, but accounts for only six hours within a 24-hour period. That’s because each of the three monitored periods documented by Cannon & Cannon (morning, midday and afternoon peak hours) accounted for only two hours each.

“I wouldn’t be surprised if these benefits at least doubled [over a 24-hour period],” Childers cited.

But for Cleveland, bad news could be lurking just around the corner if roadway improvements are not made, he suggested. He fingered a few specifics:

- Georgetown Road/25th Street at Candies Lane and Interstate 75 Southbound ramps: He said major roadway and alignment modifications are necessary. “If traffic continues to grow, this is going to become a serious problem,” Childers warned, and then added, “It’s not critical now [but it will be].” He said he understands the Tennessee Department of Transportation is aware of the issues and is working to correct them.

- 25th Street at Westside Drive/Georgetown Road: Turn lane improvements are necessary and Childers pointed out he understands a TDOT project to correct some of these issues is pending.

- 25th Street at Peerless Road: Turn lane improvements are needed. Childers said this junction has more problems than originally thought; however, he suggested turn lanes are doable and that grants for funding them might be available. With the addition of one or more key turn lanes, “... You can get some bang for your buck,” he stressed.

- 25th Street at North Ocoee Street: Childers stopped short of calling it a horror story and even suggested some alternatives might exist that TDOT engineers have not considered. He said he understands a past TDOT proposal called for a “wrecking ball” approach that would have added multiple lanes, but would have had a negative impact on several area businesses. He suggested a less expensive option that might include diverting some of the traffic to two other intersections: 25th Street at Chambliss Avenue/Henderson Avenue and 25th Street at Julian Drive/Parker Street.

“I think there are some things that could be done without bringing a wrecking ball to the whole area,” Childers said. “I’m just throwing that out here ... there are some possible ways it can be handled differently.”

The Cannon & Cannon engineer said he hopes TDOT will “revisit” the whole 25th Street/North Ocoee Street project.

- 25th Street at Little Street/Vista Drive (at McDonald’s): Childers believes a new traffic signal here could take some pressure off neighboring intersections and their cycles. “This is something that might need to be looked at,” he noted. “Just from our timing standpoint, if you were going to put in a signal [somewhere in the gap between Georgetown Road and Peerless Road], it looks like this would be the place.”

Motorists who use this tricky crossover regularly might also point to the safety improvements that could be created by a traffic signal, he suggested.

Childers acknowledged some of the roadway improvements (lanes) that he has suggested in the 25th Street Corridor study might already have been debated in past years. However, such physical enhancements will be necessary for 25th Street to attain its best possible traffic flow, Childers stressed.

Bart Borden, vice president of CU’s Electric Division which includes the city’s traffic signalization program, confirmed Childers will make the same detailed report during a future session of the Cleveland City Council.

Like Bacon and Childers, Borden said traffic engineers will continue to monitor the 25th Street Corridor and that “tweaks” will continue to be made in the work that has already been completed.

Borden said CU remains open to public comments, questions and concerns about traffic flow on 25th Street or other city arteries. Prior to the 25th Street Corridor study, and during it, CU investigated motorist complaints about the thoroughfare, he stressed.

“We have received some complaints that are real and we’ve received some complaints that are perceived,” Borden told the utility board.

Regardless, part of Bacon’s job has been to investigate each issue and to determine if the complaints can be verified, he added.

Although the 25th Street Corridor study is now complete, and most of the traffic signal changes have been made, CU traffic engineers will continue to monitor the roadway, Borden stressed.

It wasn’t said in so many words during Thursday’s CU board session, but the underlying theme was this: the next step toward improving 25th Street Corridor traffic flow will have to be the addition of lanes.

And that dime will be either on the City of Cleveland, the state of Tennessee ... or both.